The Advanced Microgrid: Integration and Interoperability

SANDIA REPORT

SAND2014-1535

Unlimited Release

Printed March 2014

The Advanced Microgrid

Integration and Interoperability

Ward Bower, Ward Bower Innovations LLC

Dan Ton, U.S. Department of Energy; Office of Electricity Delivery & Energy Reliability

Ross Guttromson, Sandia National Laboratories

Steve Glover, Sandia National Laboratories

Jason Stamp, Sandia National Laboratories

Dhruv Bhatnagar, Sandia National Laboratories

Jim Reilly, Reilly Associates

Prepared by

Sandia National Laboratories

Albuquerque, New Mexico 87185 and Livermore, California 94550

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation,

a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s

National Nuclear Security Administration under contract DE-AC04-94AL85000.

Approved for public release; further dissemination unlimited.

Issued by Sandia National Laboratories, operated for the United States Department of Energy by

Sandia Corporation.

NOTICE: This report was prepared as an account of work sponsored by an agency of the United

States Government. Neither the United States Government, nor any agency thereof, nor any of

their employees, nor any of their contractors, subcontractors, or their employees, make any

warranty, express or implied, or assume any legal liability or responsibility for the accuracy,

completeness, or usefulness of any information, apparatus, product, or process disclosed, or

represent that its use would not infringe privately owned rights. Reference herein to any specific

commercial product, process, or service by trade name, trademark, manufacturer, or otherwise,

does not necessarily constitute or imply its endorsement, recommendation, or favoring by the

United States Government, any agency thereof, or any of their contractors or subcontractors. The

views and opinions expressed herein do not necessarily state or reflect those of the United States

Government, any agency thereof, or any of their contractors.

Printed in the United States of America. This report has been reproduced directly from the best

available copy.

Available to DOE and DOE contractors from

U.S. Department of Energy

Office of Scientific and Technical Information

P.O. Box 62

Oak Ridge, TN 37831

Telephone: (865) 576-8401

Facsimile: (865) 576-5728

E-Mail: [email protected]

Online ordering: http://www.osti.gov/bridge

Available to the public from

U.S. Department of Commerce

National Technical Information Service

5285 Port Royal Rd.

Springfield, VA 22161

Telephone: (800) 553-6847

Facsimile: (703) 605-6900

E-Mail: [email protected]

Online order: http://www.ntis.gov/help/ordermethods.asp?loc=7-4-0#online

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Unlimited Release

Printed March 2014

The Advanced Microgrid

Integration and Interoperability

Ward Bower, Ward Bower Innovations LLC

Dan Ton, U.S. Department of Energy; Office of Electricity Delivery & Energy Reliability

Ross Guttromson, Sandia National Laboratories, Electric Power Systems Research Dept.

Steve Glover, Sandia National Laboratories, Electrical Science and Experiments Dept.

Jason Stamp, Sandia National Laboratories, Military and Energy Systems Analysis Dept.

Dhruv Bhatnagar, Sandia National Laboratories, Electric Power Systems Research Dept.

Jim Reilly, Reilly Associates

Sandia National Laboratories

P.O. Box 5800

Albuquerque, New Mexico 87185

Abstract

This white paper focuses on “advanced microgrids,” but sections do, out of necessity,

reference today’s commercially available systems and installations in order to clearly

distinguish the differences and advances. Advanced microgrids have been identified as

being a necessary part of the modern electrical grid through a two DOE microgrid

workshops,

’

the National Institute of Standards and Technology,

Smart Grid

Interoperability Panel and other related sources.

With their grid-interconnectivity advantages, advanced microgrids will improve system

energy efficiency and reliability and provide enabling technologies for grid-independence

to end-user sites. One popular definition that has been evolved and is used in multiple

references is that a microgrid is a group of interconnected loads and distributed-energy

resources within clearly defined electrical boundaries that acts as a single controllable

entity with respect to the grid. A microgrid can connect and disconnect from the grid to

enable it to operate in both grid-connected or island-mode. Further, an advanced

microgrid can then be loosely defined as a dynamic microgrid.

The value of microgrids to protect the nation’s electrical grid from power outages is

becoming increasingly important in the face of the increased frequency and intensity of

events caused by severe weather. Advanced microgrids will serve to mitigate power

“DOE Microgrid Workshop Report,” Office of Electricity Delivery and Energy Reliability Smart Grid R&D

Program, http://energy.gov/oe/downloads/microgrid-workshop-report-august-2011, Aug 2011.

“DOE Microgrid Workshop Report,” Office of Electricity Delivery and Energy Reliability Smart Grid R&D

Program, http://energy.gov/oe/downloads/2012-doe-microgrid-workshop-summary-report-september-2012, Sep

2012.

SGIP webpage for applicable Smart Grid Interconnections, http://www.sgip.org/#sthash.6Gcyft6W.dpbs.

“DOE Microgrid Workshop Report,” Office of Electricity Delivery and Energy Reliability Smart Grid R&D

Program, http://energy.gov/oe/downloads/2012-doe-microgrid-workshop-summary-report-september-2012, Sep

2012.

disruption economic impacts.

Advanced microgrids will contain all the essential

elements of a large-scale grid, such as the ability to (a) balance electrical demand with

sources, (b) schedule the dispatch of resources, and (c) preserve grid reliability (both

adequacy and security). In addition to these basic features, an advanced microgrid will

also be able to interact with, connect to, and disconnect from another grid.

An advanced microgrid is aptly named “micro” in the sense that a power rating of 1 MW

(plus or minus one order of magnitude) is approximately a million times smaller than the

U.S. power grid’s peak load of 1 TW. Some of the complexities required for a large grid

such as complicated market operation systems, state estimation systems, complex

resource commitment, and dispatch algorithms will be simplified. New advanced

microgrids will enable the user the flexibility to securely manage the reliability and

resiliency of the system and connected loads. By shifting resources and partitioning the

systems in different configurations, a system-survival resiliency essentially is created.

System owners can then optimally use system resources to address threats and potential

consequences, and even respond to short-time-frame priority changes that may occur.

Whether the primary driver for establishing a microgrid is cost saving, surety, or

reliability, benefits will accrue to the system owner.

Acknowledgments

The authors wish to acknowledge the many experts that provided guidance and information for

this document. The members NIST and the Smart Grid Interoperability Panel and its

subgroups provided up-to-date and valuable information related to their proactive work on

architectures of smart grid interoperability, required standards and codes, microgrid

architecture, and testing. National laboratory experts provided guidance and are continuing

work to develop critical tools to enable advanced microgrid developments and evaluate value

added to installations of the future. Members of industry and utilities shared their experiences

with installations that are already providing highly reliable microgrids for critical loads and for

economic benefits to the owner. Thanks also to Lisa Sena-Henderson of Sandia National

Laboratories for creating many of the graphics for the document. This project was funded by

the US Department of Energy Office of Electricity Delivery and Energy Reliability Smart Grid

R&D Program.

Executive Office of the President, “Economic Benefits of Increasing Electric Grid Resilience to Weather Outages,”

Aug 2013.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Contents

Acknowledgments................................................................................................................................. 4

Contents ................................................................................................................................................ 5

List of Figures ....................................................................................................................................... 6

List of Tables ........................................................................................................................................ 6

Acronyms and Abbreviations ............................................................................................................... 7

Executive Summary .............................................................................................................................. 9

1. Introduction and Background ....................................................................................................... 11

2. Vision—Concept for Advanced Microgrids ................................................................................. 15

3. Advanced Microgrid Objectives ................................................................................................... 16

4. Advanced Microgrid Program Scope............................................................................................ 17

5. Advanced Microgrid Operational Modes ..................................................................................... 20

5.1 Interconnected and Islanded Operation .............................................................................. 20

5.2 Dispatched, Scheduled, and Autonomous Microgrid Operation ........................................ 20

5.3 Commanded Shutdown, Ramp-Up and Ramp-Down While Grid-Interconnected ............ 22

5.4 Black Start In an Islanded State ......................................................................................... 22

6. Advanced Microgrid System Architecture ................................................................................... 23

6.1 System Architecture ........................................................................................................... 23

6.2 Microgrid Control and Operation ....................................................................................... 24

7. Advanced Microgrid Technical Challenges.................................................................................. 25

7.1 Operations and Control ...................................................................................................... 25

7.2 Energy Storage ................................................................................................................... 27

7.3 Component Designs and Compatibility ............................................................................. 27

7.4 Analytical Tools ................................................................................................................. 29

7.5 Reliability ........................................................................................................................... 29

7.6 Communications ................................................................................................................. 30

8. List of Advanced Microgrid Development Impact Areas............................................................. 34

8.1 Regulatory Rules and Regulations ..................................................................................... 34

8.2 Advanced Microgrid System Adoption .............................................................................. 35

8.3 Consumer Awareness ......................................................................................................... 35

8.4 Customer Rights ................................................................................................................. 35

8.5 System Siting and Permitting for Interconnection ............................................................. 35

8.6 Reliability Parameters ........................................................................................................ 36

8.7 Cybersecurity ...................................................................................................................... 36

8.8 Market Access for Electric Power ...................................................................................... 36

8.9 Retail Participation ............................................................................................................. 37

8.10 Ownership .......................................................................................................................... 37

8.11 Ownership Rate Structure .................................................................................................. 37

8.12 Franchise Rights ................................................................................................................. 37

8.13 Wholesale Market Access .................................................................................................. 38

8.15 Transmission and Distribution Market Access .................................................................. 38

8.16 Value Proposition ............................................................................................................... 39

8.17 Externality Pricing .............................................................................................................. 39

8.18 Utility Revenue and Rate Models ...................................................................................... 39

8.19 Financing ............................................................................................................................ 40

8.20 Restrictions ......................................................................................................................... 40

8.21 Grid Resilience ................................................................................................................... 41

8.22 Regulatory Barriers ............................................................................................................ 42

9. “Advanced Microgrid” Considerations for Systems..................................................................... 42

9.1 Approaches to Deploying Microgrid Applications ............................................................ 42

9.2 Today’s Microgrid Installations ......................................................................................... 43

10. Standards and Codes for Advanced Microgrids ......................................................................... 44

10.1 Interconnection ................................................................................................................... 45

10.2 Microcontrollers ................................................................................................................. 47

10.3 Code Requirements ............................................................................................................ 48

10.4 The NIST Interoperability Framework ............................................................................... 48

10.5 Other Standards .................................................................................................................. 48

10.6 Special Cases ...................................................................................................................... 48

10.7 Smart Grid Interoperability Panel ...................................................................................... 49

11. Summary ..................................................................................................................................... 49

12. References ................................................................................................................................... 49

Distribution ......................................................................................................................................... 52

List of Figures

Figure 1. Increasing numbers of natural disasters in the U.S. ........................................................ 14

Figure 2. Roadmap to evolving to the dynamic microgrid............................................................. 14

Figure 3. Advanced microgrid growth showing contributors and essential technologies. ............. 15

Figure 4. Microgrid categories and examples of interconnectivity. ............................................... 17

Figure 5. Projected worldwide microgrid market (2012–2018). Source: Pike Research

(Forbes.com) ............................................................................................................................... 20

Figure 6. Voltage and current plot from the SEL relay for the voltage-sag event. ........................ 22

Figure 7. Sandia National Laboratories’ secure, scalable microgrid test bed: a flexible platform for

collective microgrid research, development and validations. ..................................................... 24

Figure 8. European extension of the DRGS SGIP architecture ..................................................... 24

Figure 9. Hierarchical control levels in networked microgrids (to be released Q1 2014). ............ 27

Figure 10. SEGIS interconnectivity advances applied to inverters. ............................................. 28

Figure 11. Depiction of possible energy sources and interconnects for microgrids. ................... 44

Figure 12. The IEEE 2030 suite of standards and guides for smart grids. ................................... 46

List of Tables

Table 1. Important Advanced Microgrid Contributing Elements ................................................. 18

Table 2. Today’s DOE Microgrid Program Applications—Power Categories ............................ 19

Table 3. Advanced Microgrid-Relevant IEEE Standards Description and Status ........................ 46

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Acronyms and Abbreviations

ASHRAE American Society of Heating, Refrigerating, & Air-Conditioning Engineers

BACnet Building Automation and Control Networks

CERTS Consortium of Electric Reliability Solutions

CHP combined heat and power

CIP critical infrastructure protection

DER distributed energy resource

DER-CAM Distributed Energy Resources Customer Adoption Model

DEWG Domain Expert Working Group

DG distributed generation

DNP3 distributed network protocol

DOE OE U.S. DOE Office of Electricity Delivery and Energy Reliability

DR distributed resource

DRGS Distributed Renewables, Generators, and Storage

DSL digital subscriber line

DSO distribution system operator

EMS energy-management system

EPS electric power system

IEC International Electrotechnical Commission

IEEE Institute of Electrical and Electronic Engineers

ISO International Organization for Standardization

LVRT low-voltage ride through

MO market operator

μEMS microgrid energy-management system

NERC North American Electric Reliability Corporation

NIST National Institute of Standards and Technology

NREL National Renewable Energy Laboratory

PCC point of common coupling

PG&E Pacific Gas & Electric

PMU phasor measurement unit

PRM Performance Reliability Model

PV photovoltaic(s)

QF (FERC-jurisdictional) qualifying facility

QOS quality of service

R&D research and development

RTO Regional Transmission Operators

SCADA supervisory control and data acquisition

SEGIS Solar Energy Grid Integration Systems

SEL Schweitzer Engineering Laboratories

SGIP Smart Grid Interoperability Panel

SPIDERS Smart Power Infrastructure Demonstration for Energy Reliability and Security

T&D transmission and distribution

TMO Technology Management Optimization

UPS uninterrupted power supply

VAR Volt-Ampere reactive

VLAN virtual local-area network

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Executive Summary

This white paper is organized to provide a synopsis of many elements of microgrid component

technologies and system configurations that can subsequently be used for an “advanced microgrid”

development activity. The paper is written as a compilation of microgrid status, advanced microgrid

goals and requirements, new challenges and opportunities, tools for designs, and tools to strengthen

infrastructure and standards activities. It is written to complement workshop reports and information

provided by The United Stated Department of Energy Office of Electricity Delivery and Energy

Reliability Smart Grid R&D Program and other microgrid conference proceedings.

The introduction and background section provides reviews at an overview level but reveal today’s

critical needs such as improved resiliency of our nation’s electric grid. It includes some of the

developments leading up to today’s microgrid status and progresses to the needs for moving forward

from a disparity of microgrid ideas, designs, purposes, and control methodologies. Two DOE

workshops have provided industry input and prioritizations for the needs of an advanced microgrid.

Other important interoperability activities such as the Smart Grid Interoperability Panel being

directed by the National Institute for Standards and Technology are described.

An indispensable term attached to the description of the functions of advanced microgrids is

“automatic.” Today’s microgrid installations exhibit some automatic functions such as automatic

disconnect and reconnect as part of the built-in controls. Automatic load shedding is another. Many

new functionality requirements, now on the horizon, will be required to be compatible with

interconnects of the future smart grid. A second indispensable descriptive word is “interoperability.”

Challenges and opportunities are discussed in the introduction to point out anticipated impacts and

value added for a reliable and stable power supply through the nation’s electric grid that will be

coupled with an aggregation of microgrids. The interconnectivity and new functionalities will work

together to improve the grid’s power quality, reliability, and resilience, while reducing overall cost.

Standards will be a huge part of bringing the technologies and interconnect requirements up to speed.

The reader is reminded that much basic technology does exist today, but some products are often not

well matched and much of existing technology deserves improvements in reliability, two-way

communications, and standardization. A resulting scenario will be new or improved products such as

sensors, communications equipment, controllers, and eventually advanced microgrids that do not

lock out new ideas or the ability to interconnect with others of slightly different design. Today’s

developments toward an advanced microgrid are already moving forward but sometimes in a

disparate manner.

Deploying advanced microgrid systems will include various forms of energy storage, depending

upon system drivers. A microgrid designed to provide critical power during and after disruptive

events such as storms will use energy storage or will maintain its own spinning reserve. There will be

many tradeoffs. An advanced microgrid designed to improve the economics of a building will likely

use batteries as energy storage and will cycle power to and from the grid to benefit system

economics. Advanced microgrids with economic drivers may use time-of-day pricing or peak-

demand charges to determine when and whether energy is returned to or drawn from the grid. It is

likely there will be no two identical advance microgrids in the near-term because the drivers will

vary, but it is necessary to establish the infrastructure to handle them all.

This paper provides a vision section that bundles the informations and concepts provided in the paper

and that when aggregated shape the vision for an advanced microgrid system. The vision creates an

image of a viable advanced microgrid model that integrates features crucial to achieving high-value

microgrid system applications interconnected with the utility grid and additional microgrids.

Advanced hardware, intelligent inverters, smart controllers, and compatible communications will be

the enabling technologies mix to maximize economics and operational benefits of advanced

microgrid systems. Advanced and secure communication interfaces and smart controls will increase

the value of the energy provided by these advanced microgrid systems. The reliability, resilience, and

interoperable electrical service for conventional and advanced microgrid customers is vastly

improved over results of today’s installed microgrids.

The objectives and scope of advanced microgrid development goals are expanded beyond today’s

microgrid deployments within this white paper. Discussion focuses on systems that are less than

several megawatts but much larger systems will evolve from expansion of the scalable systems and

by using many of the basics being developed. The flow of the paper advances from operations mode

descriptions, such as interconnected and islanded modes with controls, through dispatched,

scheduled, and autonomous operation. The system-architecture discussion addresses the microgrid

functionalities, the applications of energy storage, and controls in a detailed overview. A detailed

discussion on tools, reliability, and communications provides valuable insights into many options for

advanced microgrid developments and designs.

The list of advanced microgrid impacts is extensive and is covered through discussions, definitions,

opportunities, and challenges. The many new goals and applications evolving for microgrids are

considered in the discussions of impacts and desired results.

Standards and codes play an essential role in moving forward for both the smart grid and compatible

advanced microgrids. The status of standards and codes, methodologies being employed to move

standards forward to enable advanced microgrid interoperability with the more intelligent electrical

grid, and the discussion of domestic and international activities provides a snapshot of the essential

work. It must be noted that microgrid and smart-grid components and systems are evolving quickly

and fast-tracks for standards will be needed.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

1. Introduction and Background

Microgrid concepts and definitions are in flux as their benefits in terms of integrating renewables,

cost savings, and grid reliability and resilience are acknowledged. Early microgrid definitions have

expanded from their islanded generation and load support to include utility support, and managing

generation and load as a part of a more resilient electric power system (EPS). Along with broadened

definitions, the scale of microgrids is changing from <1 MW to 2–10 MW, and 60–100 MW in

coming years. Many of these changed concepts and definitions will be developed and will become

essential parts of new “advanced microgrids” interconnected to smart utility grids or other

microgrids.

The U.S. government has recognized the need for increased surety and resilience of the nation’s

electric grid in order to reach goals for energy independence since the publishing of the Energy

Independence and Security Act of 2007.

This white paper provides an overview of critical elements

of and pathways to the successful pervasive implementation of innovative advanced microgrid

systems that can play important roles in future distributed electrical independence. Well-designed

microgrids have been in existence for over a decade and they have proven their worth in several

installations when natural disasters or grid disruptions occurred. This paper will use some of the

existing installations and technology information (use cases) as a base from which advanced

microgrids with intelligence, automation, secure communications, and added resilience for the utility

can be developed.

The U.S. DOE Office of Electricity Delivery and Energy Reliability (OE) has designated the research

and development (R&D) of next-generation microgrids systems a high priority. The DOE’s OE has

allocated funding for microgrid R&D to meet its 2020 goals “to develop commercial-scale microgrid

systems (capacity <10 MW) capable of reducing outage time of required loads by >98% at a cost

comparable to nonintegrated baseline solutions (uninterrupted power supply [UPS] plus diesel

genset), while reducing emissions by >20% and improving system energy efficiencies by >20%, by

2020.”

The DOE Advanced Microgrid Program is aimed at using technology advances and developing or

using models that accurately depict functionalities, performance, systems compatibilities, protection

methodology, and ultimately deploying hardware. Deployed systems will be designed to maximize

economic benefits for grid interconnectivity and islanded performance and to optimize energy

profiles and efficiencies.

A major goal for advanced microgrid systems is to develop promising new solutions to integrating

advanced microgrids capable of operating in parallel with the utility distribution system and

transitioning seamlessly to an autonomous power system complete with its controls, protection, and

operating algorithms. It is expected that advanced microgrids will be fielded in a wide variety of

electrical environments ranging from substations to building-integrated systems.

The Energy Independence and Security Act of 2007, http://www1.eere.energy.gov/femp/regulations/eisa.html.

One huge opportunity for growth and innovation is implementing innovative controls with new

microgrid technologies to prioritize critical loads, while taking into account the sum of all connected

energy sources. The resulting determinations will lead to an expanded understanding of the advanced

microgrid’s ability to provide appropriate voltage regulation, frequency stability, and power

characteristics whether grid connected or as an islanded system. R&D for certain new hardware,

including sensors, components, innovative inverters, controllers, energy-management systems

(EMSs), and advanced energy-storage systems will be required.

Applying new components to advanced microgrids will entail a suite of advanced controls,

operational methodologies and protocols, and appropriate secure communications. The standards and

codes that specify operational requirements, protocols, and safety must continue to be developed and

approved in an accelerated and timely manner. Timely testing to validate the viability, functionality,

consistency, reliability, compatibility, and interoperability with utility grids, other microgrid systems,

and in islanded states will be necessary.

It is expected that new functionalities associated with smart-grid interoperability and fielded-system

testing will serve to accelerate the advanced microgrid systems into the intelligent, distributed

electric grid and smart-grid applications. The advances in microgrid technologies will also accelerate

the continuing evolutionary processes forward in an expeditious but focused manner.

In order for a microgrid to continue operating after a transition to an islanded mode, it has to include

a compatible form of on-site power generation and/or energy storage. Without either, or both, a

microgrid could not function properly. The distributed generation (DG) and energy storage become

the foundation for the localized islanded smart-grid network. Other critical components include

energy storage and a compatible microgrid control mechanism.

Many energy resources will be used in advanced microgrids. Conventional rotating machine

technologies using renewable and fossil fuel combined with solar, wind, micro-hydro, and others will

be universally compatible. Other designs will use combined heat and power (CHP) technology. It is

estimated that a total of 518 MW of CHP capacity will be deployed in microgrids this year.

This

technology lends itself to most forms of microgrid deployments today and will continue to hold the

edge by 2018 (with an estimated 1,897 MW, representing more than $7 billion in annual revenues).

Given that CHP can be a base load electricity resource that also provides thermal energy, today’s

microgrid CHP capacity is the largest of any DG option besides diesel generators.

Benefits of advanced microgrids include:

 Supporting the existing grid infrastructure by adding resilience to the grid infrastructure, locally

compensating for the variable supply of renewable energy, and supplying ancillary services such

as Volt-Ampere reactive (VAR) support and voltage regulation to sections of the bulk power

system.

Executive Office of the President, “Economic Benefits of Increasing Electric Grid Resilience to Weather Outages,”

http://energy.gov/oe/articles/white-house-council-economic-advisers-and-energy-department-release-new-report,

Aug 2013.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

 Meeting end-user needs by ensuring UPS for critical loads, controlling power quality and

reliability at the local level, and promoting customer participation through demand-side

management and community involvement in electricity supply.

 Enabling grid modernization and interoperability of multiple smart-grid interconnections and

technologies.

 Enhancing the integration of distributed and renewable energy resources that help to reduce

carbon emissions, peak load congestion, and line losses by locating generation near demand.

In addition to the intended benefits, new innovations for advanced microgrids can be applied to

provide secure and advanced automated or dispatched controls for today’s legacy electric grid. The

advanced microgrid will initiate changes to the grid that will contain nearly self-healing sectors in the

event of natural disasters or other massive grid failures. The advanced microgrid systems will use

new communications methods that have integrated security and surety for immunity from outside

events or adversaries.

A list of the objectives for the DOE Advanced Microgrid Program includes:

 Improves the resilience of the nation’s electric distribution infrastructure

 Operates in and seamless transition between “islanded” and “grid parallel” modes

 Provides interconnection and interoperability for smart grids

 Provides cybersecurity for performance and data

 Supports power quality enhancements for connected loads

 Provides two-way communications (frequency, verification, data latency)

 Provides data management and system predictions

 Provides Volt/VAR/frequency controls and support for interconnectivity and island

 Enables dynamic local feeder reconfiguration

 Improves reliability for critical loads

 Provides outage management (i.e., number, duration, and extent)

 Balances distributed and central control

 Enables price-driven demand response

 Reduces peak loads for the interconnected grid

 Integrates with intermittent and variable output renewables

 Defers generation, transmission, and distribution investments

Numerous major disruptions in electrical service shown in Figure 1 clearly indicates the need to

develop advanced microgrid systems as a component of overall increased electric grid resilience.

Because of this report and similar reports the US DOE’s Smart Grid R&D Program directions show

microgrids to be a key building block for a smart grid. A significant number of R&D needs and

challenges have been identified for microgrids.

Executive office of the President, “Economic Benefits of Increasing Electric Grid Resilience to Weather Outages,”

http://energy.gov/oe/articles/white-house-council-economic-advisers-and-energy-department-release-new-report,

Aug 2013.

Smith, M., and Ton, D., “Key Connections: The U.S. Department of Energy’s Microgrid Initiative,” IEEE Power and

Energy Magazine, 11(4 ), July 2013.

Figure 1. Increasing numbers of natural disasters in the U.S.

Consequently, the United Stated Department of Energy Smart Grid R&D program, the DOE OE

Advanced Microgrid Program is addressing the need for a new and complete commercially available

advanced and innovative microgrid system capable of reducing outage time of critical loads by >98%

at a cost comparable to nonintegrated baseline solutions for a backup system.

A roadmap looking forward to developing dynamic microgrids that accommodate different sources

of energy, are self-sustaining –for short times and up to extended periods of operation, exhibit

advanced self-healing capabilities and provide optimal management of energy demand and supply

has been presented by at Brookhaven National Laboratories.

The anticipated evolution path is

depicted in Figure 2.

Figure 2. Roadmap to evolving to the dynamic microgrid.

Villaran, Michael, Beyond the Classic Microgrid, Government & Military Smart Grids & Microgrids Symposium,

Washington, DC, October 25, 2013

Source: National Oceanic and Atmospheric Administration

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Figure 3. Advanced microgrid growth showing contributors and essential technologies.

2. Vision—Concept for Advanced Microgrids

Figure 3 shows an illustrated pathway vision toward developing advanced microgrid systems with a

depiction of both the primary needs and the participants. All of this work requires a well-coordinated

team of experts in applying advanced technologies, funding, cost share, system logistics,

system/component testing, standards, codes, and in facilitating interconnectivity with stakeholders

and customers.

A viable advanced microgrid model that integrates the following features will be crucial to achieving

high-value applications of microgrid systems interconnected with the utility grid and additional

microgrids. Advanced hardware, intelligent inverters, smart controllers, and compatible

communications will be the enabling technology mix used to maximize a microgrid system’s

economic and operational benefits. Advanced communication interfaces and smart controls will

increase the value of the energy provided by these advanced microgrid systems. The reliability,

resilience, and interoperable electrical service for conventional and advanced microgrid customers

will be vastly improved over results of today’s installed microgrids.

Sandia National Laboratories

The term “DR islanded systems” sometimes referred to as microgrids, is used for electrical power

systems that:

 have distributed resources (DRs) and load,

 have the ability to disconnect from and parallel with the area EPS,

 include the local EPS and may include portions of the area EPS, and

 can be intentionally islanded.

DR islanded systems can be either local EPS islands or are larger EPS islands.

The defining characteristics/features of an advanced microgrid:

1) Geographically delimited or enclosed

2) Connected to the main utility grid at one point of common coupling (PCC)

3) Fed from a single substation

4) Can automatically transition to/from and operate islanded

a) Operates in a synchronized and/or current-sourced mode when utility-interconnected

b) Is compatible with system protection devices and coordination

5) Includes DR, but generator agnostic and according to needs of customer with

a) renewables (inverter interfaced),

b) fossil fuel based (rotating equipment generators), and/or

c) integrated energy storage

6) Includes an EMS with

a) controls for power exchanges, generation, load, storage, and demand response and

b) load-management controls to balance supply and demand quickly

7) Includes power and information exchanges that take place on both sides and across the PCC in

real time

3. Advanced Microgrid Objectives

The main objectives of the DOE Advanced Microgrid Program is to develop and better enable the

technologies needed to increase the ranges and applications of energy-efficient advanced microgrids.

They are capable of maintaining or improving the power quality, reliability, and resilience of the

utility grid during times of interoperability. These objectives go beyond technical advances and

include system modeling for continued evolution of microgrids. Advanced microgrids will improve

the nation’s energy infrastructure resilience, provide value added that improves electric power

quality, enables assurance of power to critical loads, creates avenues for personal security, and

supports emergency services. Spinoff devices and secure communication will be beneficiaries for

other applications such as more intelligent grid infrastructure, smarter loads that will be considered

part of the smart grid infrastructure, building energy management, and optimized demand-side

management.

Essential components to be employed will include state-of-the-art, highly integrated components,

innovative controlling devices, advanced intelligent inverters, and compatible balance-of-system

elements for all-sector energy applications. Advanced integrated inverters and controllers will also

incorporate building energy-management functions with improved compatibilities with today’s

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

building energy management. They will also communicate with new utility energy portals. New

advanced microgrids will employ products equipped for compatibility with the legacy grid of one-

way power flow, intermediate evolving grids, and the future grid of a two-way power flow. DRs such

as solar, wind, advanced demand-response systems, and optimized energy storage will be employed

in fielded advanced microgrid systems.

Figure 4 shows a pictorial diagram illustration of a microgrid with several examples of

interconnectivity. The new advanced microgrid systems will use similar, but more complex

interconnectivity, security, and combinations of renewable energy resources.

Figure 4. Microgrid categories and examples of interconnectivity.

4. Advanced Microgrid Program Scope

The scope of the Advanced Microgrid Program is to improve the reliability and increase the value of

large, innovative microgrids (initially up to 10 MW capacity). The Advanced Microgrid Program

will leapfrog current communications technology through advanced and secure communications. It

will use adaptive logic to optimize a system’s energy resources and the energy storage, and develop

new interfaces for advanced autonomous operation (islanded operation) with seamless

interconnectivity with the national electric grid. The new proven products and processes will increase

the value of advanced microgrids interconnected with today’s one-way electrical distribution

infrastructure and tomorrow’s two-way smart grid and other microgrid systems.

The newly designed inverters and controllers will interact with EMSs and provide demand response

for the interconnected grid and islanded loads. Optimized energy storage and the electric-utility

infrastructure will work together as a DG and energy storage system while increasing the utility

grid’s overall reliability and resilience.

Sandia National Laboratories

Table 1. Important Advanced Microgrid Contributing Elements

Name

Type

Element Description

Area EPS

System

The EPS that normally supplies the microgrid through their PCC.

EMS

System

EMS acting at the interface between loads and the microgrid. It communicates with smart

devices and to the outside with the microgrid control center. It aggregates the services of

the smart devices and provides further services to the microgrid. Furthermore, it can

implement some level of intelligence to fulfill the services.

Grid Control

Center

System

Control center from which the grid is operated. All required supervision and control functions

are carried out here.

Market

Operator (MO)

System

The system that procures energy and ancillary services and ensures reliability for the area

EPS. The MO may be part of the area EPS or may be a separate entity.

Microgrid

Control Center

System

The control system comprising different microgrid operator subsystems that ensures the

control & management tasks of the microgrid and the aggregation of supply and demand.

Microgrid

Controller

System

A control system able to dispatch the microgrid assets, e.g., opening/closing switches,

changing control reference points, changing generation/consumption levels, etc. Other than

the microgrid functions specifically referenced below, this use case does not specify the

objective of any of the microgrid controller functions. This use case does not specify how

the control signals are transferred or implemented in the microgrid assets.

Consumer

Person/

Org

A consumer of electricity, e.g., a private house, business building, large industrial/manufac-

turing industry or transportation system.

The consumer acts as a customer. The consumer may operate smart appliances (an

electric load with some intelligence to control it) that are flexible in demand.

DER Owner

Person/

Org

The distributed energy resource (DER) owner (or DG owner) operates a DER (or DG) that

is connected to the microgrid.

Service

Provider

Person/

Org

The service provider provides different kinds of services to the microgrid operator to support

him in the operation of the microgrid, e.g., weather forecasts or energy market analysis.

Storage Owner

Person/

Org

Provider of storage capacity for storing and delivering energy.

Aggregator

Org

Market participant that purchases/sells electricity products on behalf of two or more

consumers/generators/DERs.

In a small microgrid, the microgrid operator could act also as aggregator. In a large

microgrid, the aggregator might be a legal entity and the microgrid operator contracts with

this entity.

Grid Operator

Org

The grid operator is the operator of the grid to which the microgrid has a connection point.

The term “grid operations” refers to the undertakings of operating, building, maintaining, and

planning electric power transmission and distribution (T&D) networks.

Microgrid

Operator

Org

The microgrid operator acts as system operator in the microgrid and is responsible for

operating, maintaining, and, if necessary, developing the microgrid’s distribution system.

In some use cases, e.g., running the microgrid in an islanding mode, the microgrid should

take over the roles of the energy retailer and/or the aggregator to ensure system stability.

Retailer

Org

Entity selling electrical energy to consumers. Could also be a grid user who has a grid

connection and access contract with the transmission system operator or distribution

system operator (DSO)

DER Unit

Device

DER including DG (small photovoltaics [PV], wind, etc.) connected to the microgrid. The

device provides some degree of intelligence to facilitate monitoring and control.

Network Smart

Device

An intelligent electrical device in the microgrid that can be supervised and controlled

(e.g., sensors, circuit breakers, or switches)

Storage Unit

Device

A storage unit provides an electricity reserve to the microgrid. The device provides some

degree of intelligence to facilitate monitoring and control.

Table basics provided by James Reilly, Lead, NIST Smart Grid Interoperability Panel, Subgroup C - microgrids

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

This program emphasizes the development and ultimate demonstration of viable and complete

advanced microgrid systems in the 10 MW power-capacity range. The broad technical requirements

of advanced microgrids reveal a new level of architecture complexity for microgrid systems and

certainly the need for coordination of close collaborations and teaming.

Table 1 shows the elements that are most likely to be contributors to research, designs, and

deployment for the microgrids. Colors are used to identify the different element categories. This list

includes a collection of elements (sometimes referred to as actors) described as contributors in case

studies by the Smart Grid Interoperability Panel (SGIP) headed by the National Institute of Standards

and Technology (NIST).

Table 2 outlines the ranges of probable advanced microgrid early market applications.

Table 2. Today’s DOE Microgrid Program Applications—Power Categories

Commercial

Greater than 50 kW, three-phase and functionally expandable

Community/Campus

1–10 MW may be modular or single rating

Utility Scale

>10 MW possibly using multiple interconnected microgrids

Future advanced microgrid systems present many opportunities and potential applications. It is an

area of vigorous and likely exponential growth with a wide variety of applications and

interconnections with utility grids. Although current technology is being installed today with early

automated functionalities for supplying power to critical loads, the advanced microgrid systems will

be the favored technologies that interconnected utilities will demand as higher DER and renewable

energy generation penetration results in the need for a virtual system of advanced microgrids and a

more complex intelligent electric distribution infrastructure. Figure 5 shows a projected growth for

installations over the next five years.

Executive office of the President, “Economic Benefits of Increasing Electric Grid Resilience to Weather Outages,”

http://energy.gov/oe/articles/white-house-council-economic-advisers-and-energy-department-release-new-report,

Aug 2013.

Asmus, Peter, “Moving Microgrids into the Mainstream,” Contributor, Chart from Pike Research,

http://www.forbes.com/sites/pikeresearch/2012/10/17/moving-microgrids-into-the-mainstream/.

Figure 5. Projected worldwide microgrid market (2012–2018). Source: Pike Research (Forbes.com)

5. Advanced Microgrid Operational Modes

5.1 Interconnected and Islanded Operation

An advanced, interconnected microgrid system must meet all of the operational and interconnection

requirements that utility electric grids must meet. Advanced microgrid systems will provide high-

quality power to their loads with safety protections, synchronization, harmonic distortion limits,

voltage limits, support for devices requiring VARs, surge capabilities, and protection-device

coordination. The PCC is typically where the standards and codes in effect today apply. New rules to

cover the anti-islanding that have been in place for over a decade are being changed. The IEEE1547

Recommended Practice is commonly applied today, but there is a new recommended practice on the

way (IEEE1547a) and the revised IEEE1547.4 has provisions for allowing islanding. Results of the

evolution of the microgrid concept have been captured in the latest version of IEEE1547.4. Seamless

transfers from grid-interactive to islanded modes will become commonplace. Advanced microgrids

will be required to meet the new IEEE1547a as its new interconnection standard once it is published

in the U.S. Other standards are also likely to provide requirements for microgrid components and

systems as harmonization of international and domestic standards evolves. Regardless, R&D for

advanced microgrid systems must be broad-base in order to meet today’s interconnect standards, but

also to support utility value propositions, such as the supply of fault current, that may yet to be

reflected in current standards.

5.2 Dispatched, Scheduled, and Autonomous Microgrid Operation

Whether future advanced microgrid support will be dispatched, scheduled, or automatic will depend

on many factors such as but not limited to

 power throughput capabilities of the microgrid’s resident controller or inverter-controller,

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

 speed of detection and speed of response of all equipment,

 communications and the need for dispatch,

 reliability of all equipment,

 number and locations of microgrids on the same feeder,

 energy storage capacity and peak power delivery, and

 codes and standards requirements.

Advanced microgrid development will provide opportunities for deploying, monitoring, and

exercising new advanced microgrid capabilities, advanced control algorithms, utility

interconnectivity, and resulting distribution system impacts as well as the impacts on local loads that

will be supplied by the microgrid in an islanded state. Automatic or dynamic utility support by

advanced microgrids will need extensive testing and analysis with a majority of the interconnected

systems. An advanced microgrid system connected to a utility grid where the majority of the power

supplied by the primary energy system should present a benign addition to the distribution system

while providing reliable backup power to the microgrid system loads.

When the smart-grid capabilities on newly developed inverters and the new controls were first

demonstrated during the DOE Solar Energy Grid Integration Systems (SEGIS) program conservative

approaches were the first steps taken by Pacific Gas & Electric (PG&E) and other utilities to allow

for scheduled VAR support as a smart-grid function. This was generally only where the needs for

distributed VAR support were predictable. Recently, however, demonstrations of dispatched and

automatic support are taking place. PG&E, for instance, reported that on March 17, 2012, a total of

four low-voltage ride-through (LVRT) events took place. The low-voltage condition was caused by

momentary phase-to-phase faults on an adjacent 12 kV circuit that was fed from the same substation

where a PV system was connected. The inverter provided power during that low-voltage event

instead of dropping off line per the current IEEE1547 requirements when the support was needed.

According to the same report, a similar event occurred at the same location when an adjacent feeder

experienced a short-circuit condition causing both A and B phases at the connected substation to

experience a voltage sag to 50% of normal, which activated the inverter’s LVRT capabilities. The

protective relays on the faulted 12 kV circuit detected the short circuit and cleared the fault in

~7 cycles. The inverters successfully rode through the event and returned to normal operation upon

clearance of the short-circuit condition. Schweitzer Engineering Laboratories (SEL) graphs were

collected and reviewed by PG&E’s Renewable Resource Development department. Figure 6 shows

the voltage and current waveforms taken from the SEL relay on the substation.

Hionis, Anastasios and Ng, Steven, “Case Study: Advanced Energy PV Inverters Ride-Through PG&E Low Voltage

Events,” http://www.google.com/#fp=492a54485f563ccb&psj=1&q=PG%26E+Case+Study+260-01, 2012.

Figure 6. Voltage and current plot from the SEL relay for the voltage-sag event.

These real-time events have demonstrated the LVRT capabilities for inverters without energy

storage. Extended periods of other smart-grid functionalities are probable with an advanced

microgrid system. Advanced microgrids will require energy storage as well as advanced controls to

autonomously transition further into an islanded state or to provide more extended periods of grid

support.

5.3 Commanded Shutdown, Ramp-Up and Ramp-Down While Grid-

Interconnected

Advanced microgrids, connected to a primary energy source such as a utility electricity distribution

system, will have built-in algorithms and communications for shutdown, start-up, and curtailment.

Each of these functionalities may also be commanded when the stability or voltage regulation of a

section of distribution line is in danger of drifting out of specification because a load/distribution

mismatch. Adequate communications methods will be necessary for these conditions.

Commanded shutdown that overrides normal shutdown processes will not be as likely, but if

intermittent renewable energy sources such as PV are linked into the system there may be a need for

curtailment, commanded startup slew rates, and energy-storage interactions.

5.4 Black Start In an Islanded State

A critical requirement of an advanced microgrid comes into play when reconnection to loads occurs

in the islanded state especially after the microgrid has been inoperable but loads are still connected.

This connection of the microgrid to the loads in the islanded state is called “black start.” Where

conditions on the main grid result in the microgrid being disconnected from the main utility, the

advanced microgrid should transition either seamlessly or as quickly as possible and continue to

operate as connected DG. During the reconnection state, the operating states of reconnecting to the

Provided by Advanced Energy

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

load reclosing must be carefully considered as must the capability of the advanced microgrid to

provide startup surges and voltage regulation.

Developing local controllers in close co-ordination with an advanced microgrid central controller

must be evaluated from the dynamic-operation point of view. Testing and studies will likely need to

be performed in a simulation and in real time. The black-start functionality will help assure power

system operation, power supply reliability, and protection to critical loads.

The restoration procedure in an advanced microgrid is somewhat similar to the approach adopted for

medium-sized power systems. Several sources within the advanced microgrid must have black-start

capabilities. A stand-by power supply and a monitoring and control scheme will likely be embedded

in the microgrid control center, but autonomous inverter functions may suffice. Black-start

functionalities within advanced microgrids will need minor changes in available standards such as

IEEE 519 for harmonics and voltage, with time-dependent or load-dependent specifications called

out for microgrids.

Load shedding may be an alternative method to assure an advanced microgrid

power supply that meets today’s interconnection standards requirements.

6. Advanced Microgrid System Architecture

6.1 System Architecture

New concepts in architecture, controls, and energy-storage application will continue to be a

necessary investment. To fully realize the environmental advantages of advanced renewable

generation resources discussed earlier in this report, power systems will continue to be pushed to

higher penetration levels of renewable sources. The impact of resource balance is broad and

complex. Systems will effectively be operating with stochastic sources and loads making power

balance, transient performance, and stability much more complex objectives to achieve. Many

solutions may be envisioned to solve this challenge—ranging from source-side management with

high-bandwidth generators, to energy storage, or demand-side management. The burden of

compensating for this new variability may also be placed in the controls/communication subsystems

with migration from centralized designs to highly distributed structures.

A critical challenge that new concepts must address is the optimal mix of power flow. Sixty Hz AC

has the historical investments within the U.S., however DC systems have advantages with regard to

increasing system efficiency by reducing the number of power conversions between the system and

non-60-Hz sources or energy storage. Networked hybrid designs may prove to be the optimal

configuration for efficiency and performance. Understanding the optimal mix to create more efficient

and resilient systems of the future is important to guide the investments being made today. Research

at the National Renewable Energy Laboratory (NREL), the Consortium of Electric Reliability

Solutions (CERTS), Sandia National Laboratories (the secure, scalable microgrid test bed shown in

Figure 7), and other institutions around the world are developing technologies to address the

challenges associated with high-penetration of renewable resources. Both the Institute of Electrical

“IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems,” Persistent

Link, http://ieeexplore.ieee.org/servlet/opac?punumber=2227.

and Electronic Engineers (IEEE) and sections of DoD are recognizing the potential value of DC and

hybrid systems through the formation of standards committees and investments in long-term

research. International efforts are harmonized with efforts such as the extension of the DRGS SGIP

Architecture shown in Figure 8.

Figure 7. Sandia National Laboratories’ secure, scalable microgrid test bed: a flexible platform for collective

microgrid research, development and validations.

Figure 8. European extension of the DRGS SGIP architecture

6.2 Microgrid Control and Operation

Microgrid controls and operational functions are being described within the SGIP as part of the

Distributed Renewables, Generators, and Storage (DRGS) Domain Expert Working Group (DEWG)

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Subgroup C - Microgrids and Hierarchical Distributed Control in terms of its functions have been

described as follows

Function 1. Frequency control

F1.1 Islanding mode

F1.2 ACE control and connected mode (like AGC)

F1.3 Frequency smoothing

F1.4 Frequency ride-through

F1.5 Emergency load-shedding

F1.6 Steady state control

F1.7 Transient control

Function 2. Volt/VAR control

F2.1. Grid-connected Volt/VAR control

F2.2. Islanding Volt/VAR control

Function 3. Grid-connected-to-islanding transition

F3.1 Intentional islanding transition

F3.2 Unintentional islanding transition

Function 4. Islanding-to-grid-connected transition

Function 5. Energy management

F5.1. Grid-connected energy management

F5.2. Islanding energy management

Function 6. Protection

Function 7. Ancillary services (grid-connected)

F6.1. Real-power-related ancillary services

F6.2. Reactive-power-related ancillary services

Function 8. Black start

Function 9. User interface and data management

7. Advanced Microgrid Technical Challenges

7.1 Operations and Control

The advanced microgrid presents major challenges from the point of view of its reliable operation

and control from the main control principles (e.g., droop control, model predictive control, multiple-

agent systems with cooperative controls) to microgrid energy-management systems (EMSs). Future

advanced microgrid systems will trend to coordinated, networked microgrid operations based on

varying ownership models (utility-owned, non-utility-owned, virtual, and their combinations). The

trends are currently being better defined across the industry.

Microgrid control strategies can be

classified into three levels: primary, secondary, and tertiary, where primary and secondary levels are

associated with microgrid operation itself, and tertiary level pertains to the coordinated operation of

the microgrid and the host (macro) grid.

Xu, Yan, Microgrid Control and Operation Use Cases (Outline), Oak Ridge National Laboratory, for NIST SGIP

Subgroup C - Microgrids and Hierarchical Distributed Control Subgroup, Jun 11, 2013.

“Trends in Microgrid Control,” IEEE PES paper to be released July 2014.

A key microgrid operation element, the control function that defines the microgrid as system that can

manage itself, operate autonomously, and properly connect to the main grid for the exchange of

power and the supply of ancillary services is the microgrid energy-management system.

A microgrid energy-management system enables interoperability of different controllers and

components needed to operate the EMS through cohesive and platform-independent interfaces. This

approach allows for flexibility and customization of deployed components and control algorithms

without sacrificing “plug-and-play” or limiting potential functionality.

Microgrid components and operational solutions exist in different configurations with different

implementations. Regardless of whether equipment and software are commercial or custom,

components should be interoperable and with interfaces that comply with functional standards

defined by the EMS.

State of the art control methods must be developed that pertain to different

control levels from the perspective of the advanced microgrid.

The hierarchical levels of control can be categorized as primary, secondary, and tertiary.

a) Primary control is the level in the control hierarchy that is based exclusively on local

measurements, which includes islanding detection, output control, and power sharing (and

balance control).

b) Secondary control, the EMS, is responsible for microgrid operation in either the grid-connected

or islanded mode.

c) Tertiary control is the highest level of control and sets long-term and “optimal” set points

depending on the host grid’s requirements. Tertiary control coordinates multiple microgrids

interacting with one another in the system and communicates requirements from the host grid

(voltage support, frequency regulation). Tertiary control is considered as part of the host grid, not

the microgrid itself.

Figure 9 depicts the hierarchical levels of control that will be applied to advanced microgrids.

Microgrid Control, Dr. Geza Joos, McGill University, Canada October 2013.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Figure 9. Hierarchical control levels in networked microgrids (to be released Q1 2014).

7.2 Energy Storage

Advanced microgrids will not exist without an energy-storage element (e.g., fossil fuel, flywheels,

batteries, capacitor banks, pumped hydro, as well as other forms). An advanced microgrid’s required

reliability and resiliency will help drive energy storage cost. These requirement demand further R&D

of design and analysis approaches to optimize energy storage selection and placement within a

microgrid to minimize capital cost and operational cost of such systems. The need for energy storage

in low-inertia power systems also drives the need for more advanced control schemes, potentially

distributed in nature, to ensure that appropriate response times support a stable system. System

efficiency targets will continue to drive minimizing how many power conversions occur in advanced

microgrids. These must take into account conversions from DC sources and storage to AC power

flow. Long-term investments in microgrid technologies must continue to target DC and hybrid

(AC/DC) architectures to fully optimize the system efficiencies.

7.3 Component Designs and Compatibility

Advanced microgrids will almost always use inverters and controllers to interface with the EMS or

other coupled microgrids. Inverters can provide many functions that enable smart-grid

interoperability. The SEGIS program was a proactive DOE-sponsored initiative to design smarter PV

systems with inverters and controllers that provided functionality for more intelligent PV and other

DERs. The SEGIS initiative provided demonstrations of these “value added functions” as part of its

final deliverables to demonstrate the advanced functionalities to the distribution grid.

The existing

standards did not allow most of the new functionalities—functionalities that are now seen as

stabilizing features and energy-saving additions to a utility distribution grid with DR

Bower, W., “Solar Energy Grid Integration Systems (SEGIS)-Adding Functionality While Maintaining Reliability

and Economics,” SPIE Conference; San Diego, CA; Aug 22, 2011.

MAIN GRID

Microgrid #3

Microgrid #2

Microgrid #1

Tertiary

Control

Secondary

Control

Microgrid

Network

Primary Control

interconnections. SEGIS feature adoption is becoming more common with scheduled and dispatched

commands for the features being used now but with rapid changes toward dynamic and autonomous

functionalities being considered and soon required for PV and other DR interconnections.

The SEGIS interconnectivity pathways developed over the three-year program are illustrated in

Figure 10.

Figure 10. SEGIS interconnectivity advances applied to inverters.

Important smart-grid interoperability functions developed and demonstrated during the SEGIS and

follow-on programs that are now available for advanced microgrid systems and the necessary

interconnectivity include:

 PV systems integration and economic optimization

 DC bus for multiple-source energy supply

 VAR support (scheduled, dispatched, and dynamic)

 LVRT functions

 System performance predictions

 Source intermittency mitigation

 Integrated communications for measurement devices, sensors, inverters, controllers, and EMSs

 Applications for phasor measurement units (PMUs)

 Mesh network, power line communications, and wireless communications alternatives

 Data collection and advanced analysis

 Anti-islanding and intentional islanding controls

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

 Power output slew rates and curtailment

 Microgrid enablement (islanded state with black start)

 Building EMSs

 Performance/economic optimizations

 Utility support (value added)

 System optimization (economics)

 System monitoring and data analysis

 Modeling

7.4 Analytical Tools

As advanced microgrids evolve in complexity, analytical tools for field projects, technologies,

control strategies, and assessing cost/benefits will be necessary. Some of the analytical tools include

GridLAB-D

A power-system simulation tool that provides valuable information to users who design and operate

electric power T&D systems and to utilities that wish to take advantage of the latest smart-grid

technology. GridLAB-D was developed by Pacific Northwest National Laboratory and is in the

public domain.

Distributed Energy Resources Customer Adoption Model (DER-CAM)

DER-CAM was developed by Lawrence Berkley National Laboratory and its functionalities and

scope include:

 Available routines to minimize annual energy costs, CO

emissions, or multiple objectives of

providing services at building microgrid level (typically buildings with 250–2000 kW peak) but

can be applied elsewhere

 Results with technology-neutral and pure-optimal results with highly variable run time

 Designation by Berkeley Lab and collaborations in the U.S., Germany, Spain, Belgium, Japan,

and Australia over ~10 years. Commercialization by Software-as-a-Service is currently under

license

Performance Reliability Model (PRM)

 Under development by Sandia National Laboratories

 Restricted access

Technology Management Optimization (TMO)

 Under development by Sandia National Laboratories

 Restricted access

7.5 Reliability

The North American Electric Reliability Corporation (NERC), which the Federal Energy Regulatory

Commission (FERC) has certified as the nation’s electric reliability organization, has developed

critical infrastructure protection (CIP) cybersecurity reliability standards. On January 18, 2008,

FERC issued Order No. 706, the final rule approving CIP reliability standards, while concurrently

directing NERC to develop significant modifications to address specific concerns.

Work continues,

with reliability being a high priority, on developments related to developing smart-grid and microgrid

strategies.

One reliability aspect of microgrid applications is related to (a) components integrated into the

microgrid systems, (b) components related to interoperability with the utility grid, and (c) whether

the microgrid’s functionality is compatible with current infrastructures. Those reliabilities are

typically assessed as mean-time-between failures (in hours) and must be assesses during a system’s

(such as a microgrid’s) design.

The reliability of the power being delivered to critical loads is another aspect of reliability. An

understandable grid-reliability measure is the number of outage minutes per year. Self-healing

features are one method for adding resilience to established electric grid infrastructure.

Advanced

microgrids are another method to improve critical-load power reliability. The microgrid basically can

be considered a redundant energy source when a viable electric grid is available.

7.6 Communications

Communication will be a critical function for advanced microgrid systems. Communication with the

DSO will be essential to ensuring safe, reliable operation as system numbers and penetration

increase. Additional communication functions will be critical to optimizing system value. Advanced

microgrids will need to use protocols based on new system standards in order to be broadly

applicable. Greater market penetration will be more attainable when communications capabilities

compatible with other standards, such as the pertinent International Electrotechnical Commission

(IEC) standards, are developed. Providing secure communications between system monitor and

control functions spread out over long distances back to a centrally located supervisory control and

data acquisition (SCADA) -type administrative control site will increase acceptability. Dedicated

virtual private networks can be implemented to specify security features and separate different user

traffic over a SCADA network.

Because microgrids lack the inertia of an interconnected power system, having a good understanding

of what is happening at any point is critical. Microgrid operating conditions can change very quickly

with incremental load or generation. PMUs are able to directly measure the state throughout the

microgrid (with near-real-time updates up to 60/second), thus providing needed visibility of the

actual operating conditions. Also, this can be useful for control the microgrid system as well (PMU

measurements are used in a control system that keeps the system operating in a safe region).

7.6.1 Distributed Measurements.

PMUs provide distributed measurements throughout the microgrid that can be useful for

understanding system operation or tuning system components or for providing additional information

in post-event analysis. Because PMU functionality is available in protective relays, voltage

regulators, reclosers, and meters, PMU measurements are readily available across the microgrid.

http://www.ferc.gov/industries/electric/indus-act/reliability/cybersecurity.asp.

Amin, Massoud, “Toward Self-healing Energy Infrastructure Systems,” IEEE Computer Applications in Power, Jan

2001.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

7.6.2 Synchronization.

PMUs are ideal for measuring voltage magnitude, angles, frequency, and slip between any two

portions of the electric system. This could be the islanded microgrid and the rest of the

interconnected power system, or this could be portions of the system within the microgrid (e.g., a

generator looped line feeder). One big benefit of using PMU measurements for resynchronizing is

that no portion of the system must be “turned off” to resynchronize the microgrid to the utility

connection.

Synchrophasor measurements can help operators quickly identify islanded portions of the system

(monitor frequency of the various PMUs).

7.6.3 Metering

With PMUs spread around the microgrid, the user can effectively see where power is flowing, where

the loads are, where the generation is, how large the load is, etc. Because users have access to voltage

and current phasors, they can see real and reactive power flows within the microgrid.

7.6.4 Anti-Islanding and Islanding Control

The inverters in today’s DR systems monitor grid parameters and disconnect when those parameters

fall outside the ranges established in IEEE1547. As the number of interconnected inverters increases,

as noted above, a more interactive method is needed to ensure that inverters will disconnect when

required, but will also ride through variations in utility operating parameters likely caused by high

demand. Communication of the need to disconnect must be fast (less than one second) and certain

(always occurs when connection to the utility is lost). The distance over which this information must

travel is potentially long, but the amount of information required is small.

7.6.5 Internal Communication

Communication within the system is critical to controlling loads and storage to optimize system

value while maintaining system safety. Distance over which data must travel will generally be

modest, unless the site is a large commercial system or microgrid. In addition to ensuring safe,

efficient system operation, a system that is connected under time-of-day and/or demand rate

structures will be trying to balance the available energy from the solar generating system, other

connected DG sources, and storage with variations in loads and utility pricing. While solar output

can change rapidly with cloud passages and loads can change with the flick of a switch, utility

demand charges are usually assessed over a 15–30 minute period, so the system has time to respond.

However, in the event of off-grid operation, the system must act quickly to prevent load from

exceeding maximum system capability (maximum inverter rating and/or available solar plus storage

system discharge capability) at any given time. If the system is not permitted to export power, then

loads, storage, or the inverter output must be controlled to avoid back feed (less than one cycle).

7.6.6 Communication Methods and Protocols

Communication types and applications in use or under consideration in some case are summarized

here.

Dedicated copper wiring. Large transmission-connected generators use dedicated copper wiring for

control, but the cost to connect with large numbers of individual DG systems would be very high.

Dedicated fiber-optic link. Substations and control centers are increasingly using fiber-optic links

for dedicated, secure communications. Dedicated fiber-optic links provide speed and reliability that

enables real-time communication with synchrophasors.

Ad hoc mesh networks. Smart, granular network topologies that use ad hoc connection methods,

whereby individual devices discover others within range to form a cooperative mesh communication

network capable of establishing a massive infrastructure with end-to-end routing links.

Continuous-carrier power line communications carriers. Used by some utilities for automated

meter reading systems. The power line communications carrier signal is lost if the connection to the

utility is lost, so this signal could be effective for inverter anti-islanding control. Drawbacks are high

cost, low bandwidth, and high power demand.

Broadband-over-power-line. This approach takes advantage of existing power-line infrastructure

to communicate data, but this technology has faced technical issues, including interference with other

radio spectrum users and interference from loads. Some systems have gone to digital multiple-carrier

modulation scheme to mitigate radio interference issues.

Ethernet. Provides communications within buildings, but must be connected to a wide-area-network

technology, such as cable television. Wide-area networks do not have sufficient reliability to support

protection functions.

Wireless local area network (IEEE802.11). Used inside and outside of buildings to provide short-

distance wireless data.

Wireless interoperability for microwave access (IEEE802.16). Provides longer range wireless

access.

Wireless metropolitan area networks (IEEE802.16d). This is a standards-based technology

enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL

(digital subscriber line). It is often used in urban environments to transmit 2 km without line-of-sight

antenna configurations and up to 10 km with unobstructed path.

Personal area networks (e.g., IEEE802.1). Provides short-distance (few meters) wireless

communications.

BACnet. Developed under the auspices of the American Society of Heating, Refrigerating, and Air-

Conditioning Engineers (ASHRAE), BACnet

is an American national standard, a European

standard, a national standard in more than 30 countries, and an International Organization for

Standardization (ISO) global standard.

Further, the protocol is supported and maintained by

ASHRAE Standing Standard Project Committee ANSI/CEA-709.1-B establishes another standard

for control networking. It provides one of the data link/physical layers of BACnet

Leased telco links. These are point-to-point communications links via leased lines that may also

include microwave-relay links and two-way radio.

BACnet® is a registered ASHRAE trademark. The website is dedicated to providing the latest information on

BACnet, “A Data Communication Protocol for Building Automation and Control Networks,” http://www.bacnet.org/.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Shared-fiber VLAN/QOS. Virtual local-area networks (VLANs) provide a secure method to

communicate using mutually isolated, optically coupled devices. The packets of information can only

pass between them via one or more dedicated routers. This also provides for a new layer of quality of

service (QOS).

Other. A variety of other technologies are available, including conventional telephone landlines,

cellular telephone, spread-spectrum radios, and pagers. Some utilities have used wireless technology

to dispatch customer loads, e.g., Nevada Power’s Cool Share program.

7.6.7 Communication for System Optimization

As communication techniques and information flow in advanced microgrids evolves, the opportunity

for further system performance optimization must be considered. Research that enhances the holistic

microgrid design and analysis, taking into account the communication flow, will become a more

significant focus of system design. Tools and design approaches that effectively allow tradeoffs

between information flow and component performance will continue to be developed.

7.6.8 External Communication

Increased microgrid applicability will be enabled for widespread use both by more than 3,000

utilities in the U.S. as well as military bases, campuses, industry, and others in need of a guaranteed

power supplies. To optimize system value, it must respond to external data, such as utility rate

structures, real-time pricing, secure dispatch signals, and weather forecasts. Security is important for

both dispatch and anti-islanding signals because a cyber-attack resulting in the simultaneous

disconnect of a number of microgrids representing significant penetration of a portion of the grid

could overwhelm the utility’s reserve capacity, causing an outage. Relative to islanding control, the

speed with which data must be transferred is lower, depending on the need, as follows:

 Spinning reserve (replacing lost capacity). Signal sent ~1/second. Thermal generation units

providing spinning reserve achieve full output in a few minutes. Hydroelectric units respond

more quickly.

 Frequency and area regulation (maintaining frequency control). Signal sent every few

seconds. Response time is over several minutes.

 Voltage regulation. Line voltage provides signal. Very fast (subcycle) response, e.g., using

droop algorithms is possible. Central dispatch is slower (few cycles).

 Peak shaving (demand response). Signal can be built into peak-demand rate structures or real-

time pricing, which may be updated at intervals of 1–60 minutes, depending on the utility. Some

utilities also dispatch loads to shave peak demand.

 Back feed control. Some systems, especially large commercial systems, may be restricted from

exporting power to the utility. Often, these systems are sized so that the system output never

exceeds load, but in the event it does or if the system is larger and uses storage to absorb excess

power, then the response must be faster than the reverse-power relay, which is typically subcycle.

8. List of Advanced Microgrid Development Impact Areas

This section provides and extensive list of impact topics that either enable, or in some cases, are

barriers to expansion of advanced microgrids. Concerns and problems are discussed as are the

advantages of developing solutions and pathways for each impact area.

8.1 Regulatory Rules and Regulations

Some of the important concerns and problems identified through microgrid case studies and

interviews include establishing best practices for (a) consistent methodologies for determining and

measuring microgrid benefits; (b) engaging customers; (c) cybersecurity methods and protocols;

(d) interoperability standards; and (e) microgrid communications and control systems, including for

autonomous operations. Some of the policy concerns identified include how best to

Thus, it appears that policies flexible enough to allow experiments, demonstrations, and pilot projects

to continue and expand, and adjustable enough to accept changes, over time, as more is learned are

needed.

As DRs capture a larger role in utility systems, the impacts on utility revenues and earnings will vary

substantially depending on the existing market and tariff structures. Increasing importance will be

associated with the ability to model utility costs and revenues based on variable rate and tariff

structures. Legitimate concerns and difficult issues are embedded in these barriers, including (a) how

reliability of service is to be assured, (b) who is ultimately responsible for assuring it, and (c) what

are fair prices both for distributed generators to receive for off- or on-peak electricity generated and

how to pay for their share of the fixed costs of any grid in which they participate.

Rate structures for both full- and partial-requirements service need to be reviewed to ensure that price

signals reflect, as accurately as practical, the time and geographic properties that affect costs and

account for the benefits (e.g., reliability, diversity, avoided generation, T&D costs, etc.) that are

conferred to the utility grid by advanced microgrid systems. The need for electricity rates that reward

demand-side management are needed along with reduced rates for non-firm standby service. Note

that several states already offer reduced standby charges for “DER customers that can provide

physical assurance that the system will not exceed a specified load during peak periods.” In many

ways, state public utility regulations will ultimately determine the details about whether, how, and

where microgrids can be built, what customers they can serve, what services they can provide, and

thus what benefits advanced microgrids can produce.

a) implement dynamic pricing;

b) refine interconnection policies;

c) adjust retail rate designs and refine rates for

partial-requirements service;

d) establish utility DER investment policies;

e) develop retail-market participation rules;

f) provide utilities with appropriate regulatory

incentives;

g) coordinate microgrid policies with other

policies intended to promote DG, electric

vehicles, and other distributed resources;

and

h) achieve consistent regulatory policies across

multiple utility-service territories, including

multiple-state, regional, and conceivably

national policies.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

8.2 Advanced Microgrid System Adoption

Except for a few states, smart-grid programs with microgrids are generally limited in scope, due in

part to today’s utility aversion to adopting the new technologies and in part to market risks.

With

the economy slowly recovering from a recession, electricity demand is unpredictable, fuel prices are

variable, and environmental policies are uncertain. This combination of factors presents sufficient

risk for public utilities to not consider new investments. Legislation at both the state and federal

levels, which requires smart-grid resource consideration that would benefit from advanced

microgrids and creates innovative financing methods, may be necessary to encourage technology

development. Other considerations, such as consumer awareness, siting and permitting processes,

reliability parameters, and cybersecurity concerns also impede deployment.

8.3 Consumer Awareness

Lack of awareness of smart-grid developments and advantages of advanced microgrid technologies

will impede their deployment.

Additionally, without policies that motivate utilities, homebuilders,

and others to implement these technologies, deployment may remain stagnant. State commissions

and legislatures should consider whether to encourage or require the use of innovations that can help

consumers understand their energy use and enable informed decisions in new applications that can

balance the energy picture. Innovative financial mechanisms could mitigate consumer risks and

enable consumers to obtain the capital necessary for investment in advanced microgrid technologies.

8.4 Customer Rights

Unless the customers own the facilities or are tenants of advanced microgrid owners, then an

advanced microgrid in New York may need to be in compliance with the state’s Home Energy Fair

Practices Act. Also, if the microgrid opts for standby service during peak demand periods, the

standby fees may have to be paid by customers. Advanced microgrid owners should have a clear

expectation of evolving local and state rules and associated fees.

8.5 System Siting and Permitting for Interconnection

A consumer who wishes to install an advanced microgrid system faces regulatory and environmental

obstacles to obtain all of the necessary siting and permitting approvals. Approvals often include

multiple rounds of approval across multiple organizations. A similar situation applies for an

industrial customer installing a grid-connected, advanced CHP system or a microgrid at its

manufacturing plant. Addressing this process will be a key factor in encouraging smart-grid and

microgrid deployment. The complexity and multitude of siting and permitting requirements for

potential owners creates a significant time and cost barrier to implementation. FERC released a

notice of proposed rulemaking on reforms to its small generator interconnection agreements and

procedures. This rulemaking is an attempt to ease the interconnection process for all generators under

20 MW that interconnect under its jurisdiction with a fast-track process for resources less than

2 MW. It addresses the issues involved for public utility transmission providers and their

U.S. Energy Information Administration, “Smart Grid Legislative and Regulatory Policies and Case Studies,”

December 2011.

Black and Veatch, “2011 Strategic Directions Survey Results,” http://bv.com/docs/reports-studies/2011-Electric-

Utility-Survey-Results.pdf, 2011.

customers.

Similar efforts by states and local jurisdictions will be helpful in easing the

interconnection process for advanced microgrids connected to intelligent grid infrastructure.

8.6 Reliability Parameters

Better component and system reliability parameters are necessary to fully address a resilient electric-

grid infrastructure. As evidenced by Hurricane Sandy in 2012, there is an immediate and increasing

need to develop more effective national standardized metrics and policies for grid reliability and

resilience. Along with the improved reliability standard, new infrastructure investment must be

identified and prioritized. Despite current reliability metrics indicating high levels of reliability in

New York City during and after the storm, much of the city was without power. Existing reliability

metrics do not provide sufficient and complete insight into operational risk that may exist under

disaster conditions. Federal and state governments are working to evaluate electric-grid

improvements to ensure continued electricity access during such disasters. New resilience metrics at

the federal and state levels will provide the necessary incentive to promote improvements, in which

smart-grid technologies and advanced microgrid systems will play a critical role.

8.7 Cybersecurity

With advanced metering and control deployment, larger data volumes must be handled, while at the

same time safeguarding privacy and addressing critical cybersecurity concerns. Threats to security

are vitally important for consumers, developers, and utilities when deploying smart-grid resources

and advanced microgrids. A large New Jersey utility, for example, does not yet permit wireless

controls on its system, limiting a number of innovative smart-grid technologies that could play a role

in addressing its needs and those of its customers. Policy which enables validation of cybersecurity

methods in communications and data handling would ensure the rights of users are protected and

appropriate safeguards are in place across the electric grid. As of 2011, three states had made

significant strides in establishing such policies, while 12 more had rulemakings in consideration.

This leaves the majority of states, and the federal government, yet to make progress on addressing

cybersecurity issues.

8.8 Market Access for Electric Power

In addition to advanced technologies being a limiting factor for deployment, the lack of electricity

market access for microgrid technologies, at both the wholesale and retail levels, and the regulations

and policies in place that restrict this access also present a barrier to the deployment of microgrids

interconnected with a smart grid. New policy is needed to ensure that these technologies are able to

provide services and to be compensated for this provision. For example, only 11 states have adopted

advanced retail metering plans, where most others are still in the study phase.

This restricts

microgrid resources, dynamic control of interconnected loads, and the dispatch of electricity services

to the distribution environment.

Federal Energy Regulatory Commission, “Small Generator Interconnection Agreements and Procedures, Notice of

Proposed Rulemaking,” 142 FERC 61,049, January 17, 2013.

U.S. Energy Information Administration, “Smart Grid Legislative and Regulatory Policies and Case Studies,”

December 2011.

Ibid.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Markets herein are defined as any avenue through which resources can participate in the electricity

system, whether at the wholesale or retail levels. It also includes technology markets, for example,

markets for microgrids, DG, and control systems. Policies that restrict electricity market access

present an obstacle to microgrid technology market development: if the products are unable to

participate on the electric system, the incentive for their production and cost reductions through

research and economies of scale are limited.

8.9 Retail Participation

Policies currently in place restrict the retail market participation of microgrids connected to smart

grids by limiting their use for a number of functions. Retail wheeling, for example, is not allowed.

A retail customer who has a microgrid, or just DG installed, cannot contract with nearby customers

to trade power. He or she must instead sell any excess power directly to the utility. This presents

higher costs to the customer as they receive lower rates for that energy relative to its purchase in the

retail market and is a disadvantage to ratepayers because wheeling through a microgrid system may

be a means of reducing the need for distribution capital investments. Other rules also present retail

restrictions. For example, an Illinois rule prohibits multiple-tenant building owners from installing

and aggregating smart meters to secure competitive rates and operate as an aggregate system.

The

same rule is easily construed to include microgrids. Considering that retail customer participation

will be essential to the microgrid connection with the smart grid by enabling increased energy

efficiency and demand response, addressing these restrictions will be important.

8.10 Ownership

Deciding who owns the electricity generating equipment and wires for linking the loads can have a

huge impact on how a microgrid functions. Mechanisms to allow sharing among one or more

customers, as an electric cooperative, as a corporation, or as a nonprofit association will be needed.

Questions such as “how much input will the end-users have on their microgrid’s operation?” and

“what are the consequences if a customer wants to leave the microgrid entirely?” will need solutions.

8.11 Ownership Rate Structure

How will a microgrid be regulated? Depending on the size, structure, and ownership model, the

microgrid can be exempt from most federal and state regulation if it meets the standards as a FERC-

jurisdictional qualifying facility (QF). The benefits of QF status include avoiding burdensome

regulations regarding rate setting, finances, construction, and operation.

8.12 Franchise Rights

Installing wires over public-access streets can trigger franchise-rights litigation. A nonutility

installing facilities and distributing electricity over public streets will get the attention of the local

utility that has a franchise in the street to construct power lines. Not only must a microgrid avoid

infringing on a utility’s franchise rights, but it also has to work with the local utility to avoid having

to go through lengthy and expensive litigation just to prove that it’s not doing so. This may require

McDermott, Karl A., “The Regulatory Dilemma: Getting Over the Fear of Price,” The Electricity Journal, 25(9), 6–

13 November 2012. http://dx.doi.org/10.1016/j.tej.2012.10.011.

Kelly, J.; Rouse, G.; and Nechas, R., “Illinois Electricity System Guiding Principles and Policy Framework,” Galvin

Electricity Initiative, July 2010.

contracting with the utility to pay for using the wires that cross public streets to avoid franchise

issues.

8.13 Wholesale Market Access

Energy storage is a microgrid technology that can be categorized under FERC policy as a regulated

transmission or distribution asset, which is allowed a fixed rate of return, or as a deregulated

generation asset, which can participate in wholesale market operations. However, the commission

does not make its policy clear on whether a single asset can provide both regulated and deregulated

service and requires any such consideration to be decided on a case by case basis.

This restricts

market access for energy storage and other smart-grid technologies. It is present in all Independent

System Operator/Regional Transmission Operators (ISO/RTO) market regions. In non-ISO/RTO

regions, a vertically integrated utility can use its assets for any purpose and recover all value that the

asset provides.

In this case, state utility regulators must ensure that smart-grid or microgrid

technologies, such as energy storage or demand response, are considered as alternatives to other

generation, transmission, and distribution investments.

The lack of ancillary service markets for inertial response, governor response, black start, and voltage

regulation in most regions, also presents a barrier to deploying microgrid resources in ISO/RTO

markets. Currently, on-line spinning generation provides inertial response, but does not get paid for

this service. The advanced microgrid can function as a spinning reserve with total-energy and peak-

power limitations when compared to the utility grid and fall under the same rules. As generation

from microgrids increase, there will be a need to ensure access to inertia from nontraditional

resources. Dynamic resources, such as energy storage or advanced inverters, are capable of providing

this service, but as there is no market compensation, there is no incentive for their use.

Similarly,

bundling reliability services in a transmission utility’s open-access transmission tariff may restrict

deploying resources which provide individual, or a subset of, reliability services.

8.15 Transmission and Distribution Market Access

The separation between planning and operations at the generation, transmission, and distribution

level is no longer sustainable as new technologies will have to be considered under both planning and

operational realms and across the different system boundaries. This separation limits identifying the

need for smart-grid resources that will use advanced microgrid systems. As these resources enter the

system, policies will be needed that establish new operating methods that take new technologies’

capabilities into account.

FERC Order 1000 establishes regional planning coordination for transmission and requires

considering “nonwire” resources to meet needs. This is an important first step in opening up the

Federal Energy Regulatory Commission, “Notice of Proposed Rulemaking: Third-Party Provision of Ancillary

Services; Accounting and Financial Reporting for New Electric Storage Technologies,” 139 FERC 61,245, June 22,

2012.

Hayashi, Paul M., Goo, James Yeoung-Jia, and Chamberlain, Wm. Clif, “Vertical Economies: The Case of U.S.

Electric Utility Industry, 1983-87,” Southern Economic Journal, 63(3), 710–725 (Jan., 1997).

Morren, J., de Haan, S.W., Kling, W.L., & Ferreira, J.A. “Wind turbines emulating inertia and supporting primary

frequency control.” IEEE Transactions on Power Systems, 21(1), 433–434, 2006.

Morrison, J. A. “The clash of industry visions,” The Electricity Journal, 18(1), 14–30. 2005.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

transmission market to smart-grid resources. However, considering that many of these technologies

will reside at the distribution level, it is incumbent on regional planners to ensure that distribution

resources including advanced microgrids are taken into account and considered along with bulk

transmission. Transmission operation and planning must reach into the distribution level in order to

exploit existing and emerging communications and smart resources. The lack of defined policy

around this issue will most likely restrict the access of smart-grid technologies along with microgrid

supplementary resources to long-term T&D capacity planning methods.

8.16 Value Proposition

Ensuring advanced technology applications and market access will help advanced microgrid

resources become one of the technology options evaluated for investment. Appropriate economic

valuations will help ensure their deployment. A few policy barriers restrict potential users from

determining their full value proposition. They include the lack of externality pricing, limitations in

utility revenue and retail rate models, and the lack of financing options. Policy which ensures that all

benefits and costs, including social benefits and costs, are considered when infrastructure is

evaluated for deployment will help to deploy technologies that meet system reliability and resilience

needs at the lowest cost.

8.17 Externality Pricing

The lack of externality pricing allows the market to ignore the full cost of electricity grid resources.

Carbon, for example, is not priced in the marketplace. Policies, such as renewable portfolio standards

and renewable incentives, have been in place for a number of years; however, they only address

generation assets, leaving out many other smart-grid and advanced microgrid technologies.

Microgrids can inherently improve building control systems and demand response programs, which

would have an improved value proposition with the consideration of externalities. While pricing

these externalities might be a difficult process, other mechanisms would force the consideration of

positive and negative externalities in the evaluation process for new resource deployment, such as

energy-efficiency and clean-capacity standards.

Advanced microgrid benefits can vary widely depending on their physical location in the utility-

system’s distributed macrogrid and the size and scope of microgrid operations. In some cases,

because consumers value the benefits microgrids can provide, owners will be willing and able to pay

all or nearly all of the associated costs. In that circumstance, utility-system benefits can be highly

cost-effective, irrespective of the benefits and costs to the microgrid’s owners.

8.18 Utility Revenue and Rate Models

Some regulatory policies do not allow the recovery of investment in modern grid technologies. In

most states, investor-owned utilities are incentivized to address system peak issues by investing in

new generation facilities rather than supporting consumer-side demand response and energy-

efficiency opportunities.

Public utilities are rewarded for increasing electricity consumption

because their revenue depends on electricity sales. That scenario restricts the likelihood that they will

Chu, L.Y., and Sappington, D.E., “Motivating energy suppliers to promote energy conservation,” Journal of

Regulatory Economics, 1–19, 2013.

create programs for demand response or allow grid-interactive, customer-deployed, smart-grid

resources without a regulatory mandate.

Similar to utility revenue models, retail electricity rate models create a disincentive for the customer

to consider deploying microgrid systems. Only 12 states have adopted dynamic pricing or have

begun studies into evaluating the potential for dynamic pricing on their systems. This leaves 38 states

that do not consider dynamic pricing in retail rates.

A policy that implements dynamic pricing

could provide a price signal for deploying smart-grid resources. Representing real electricity costs to

consumers, depending on the time of day and usage, might increase power system efficiency.

8.19 Financing

Policy that governs electricity system asset financing provides an advantage for traditional system

resources. T&D capital resources obtain thirty or more years of financing under regulator-approved

rate base, while smaller investments by ratepayers and third parties, who are likely to represent a

significant proportion of microgrid asset owners, must have shorter payback periods. This creates

disconnects between utilities, independent developers, and retail customers when considering new

infrastructure deployment to meet electricity system needs. Policymakers must ensure that

appropriate legislative incentives are in place, whether through tax credits or low-rate loan

guarantees, which level the playing field with utility-owned capital investment. In addition, many

utilities have generation assets that are not yet depreciated and they are not willing to leave them

stranded in favor of energy-efficiency programs or microgrid technologies. Policies that allow faster

depreciation of these assets’ remaining book value, while replacing them with modern microgrid and

smart-grid assets, could be one means of eliminating this issue.

8.20 Restrictions

Advanced microgrid technologies have the potential to significantly impact today’s legacy electric

grid and more importantly the future smart grid. The smart grid will emerge slowly because the

current system will require considerable infrastructure investment to maintain reliability and ensure

resilience as assets get older, demands on the system increase because of more variable loads and

generation, and the system moves toward lower carbon emissions. A number of barriers restrict these

technologies’ further deployment.

 Consideration of these resources amongst alternatives when the electricity grid requires new

infrastructure

 Ability of these resources to participate in electricity markets, whether wholesale generation,

transmission, distribution, or retail

 Deployment value propositions

State and federal lawmakers and regulators must ensure that these policy barriers are addressed to

give microgrid and smart-grid technologies fair consideration for deployment.

U.S. Energy Information Administration, “Smart Grid Legislative and Regulatory Policies and Case Studies,”

December 2011.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

8.21 Grid Resilience

The U.S. electric grid is vulnerable to natural disasters, severe weather, and acts of sabotage. The

recent report prepared by the President’s Council of Economic Advisers and the U.S. Department of

Energy’s Office of Electricity Delivery and Energy Reliability, with assistance from the White House

Office of Science and Technology estimates “the average annual cost of power outages caused by

severe weather to be between $18 billion and $33 billion per year.

In a year with record-breaking

storms, the cost can be much higher. For example, weather-related outages cost the economy

between $40 billion and $75 billion in 2008, the year of Hurricane Ike.” Although it is not a

certainty, costs related to loss of electric power are expected to rise because of climate change.

From this report and a host of others, it is evident that a more resilient electric grid must become a

high priority in reconfiguring and updating the nation’s electric power distribution and transmission.

Evolution of smart-grid technology designed to increase resilience will result in reduced outage time

and even prevent the loss of electric power to critical loads in cities and critical infrastructure. Smart-

grid improvements will also enhance national security. The emerging smart grid and the components

of advanced microgrids must, however, be protected against cyber attacks and maintain adequate

autonomy to keep critical loads energized.

Advanced microgrids with energy storage are cited in this paper to “achieve a good match between

generation and load.” An advanced microgrid with economically and functionally optimized energy

storage will provide voltage and frequency regulation to maintain desired electric grid balance

between loads and generated power in many distribution-system sectors. Renewable energy

supported by alternative resources and energy storage is already supporting a high penetration of

intermittent renewable energy in some grid sectors. An advanced microgrid will have a built-in

ability to separate and isolate itself from the utility seamlessly with little or no disruption to the loads

within the microgrid. The separation can occur as a result of scheduled, dispatched, or autonomous

commands. An advanced microgrid can then be dispatched or automatically reconnected to an

electric grid when conditions return to normal. Advanced microgrids will automatically synchronize

to primary power sources before reconnecting to the restored grid. Technologies including advanced

and secure communication and controls, building controls, DG, and inverters already are

commercially available, but even more advanced functionality will be needed for advanced microgrid

systems. CHP systems have demonstrated their potential by maintaining power and heat at several

institutions following Superstorm Sandy.

Resilience is increasingly important as climate change

increases severe weather’s frequency and intensity. Greenhouse gas emissions are elevating air and

water temperatures around the world. Scientific research predicts more severe hurricanes, winter

storms, heat waves, floods, and other extreme weather events as being among the changes in climate

induced by anthropogenic greenhouse gas emissions.

Executive office of the President, “Economic Benefits of Increasing Electric Grid Resilience to Weather Outages,”

http://energy.gov/oe/articles/white-house-council-economic-advisers-and-energy-department-release-new-report,

Aug 2013.

“CHP Kept Schools, Hospitals Running Amid Hurricane Sandy,” http://www.ase.org/efficiencynews/chp-kept-

schools-hospitals-running-amid-hurricane-sandy, Dec. 11, 2012.

8.22 Regulatory Barriers

At the present time, the distribution grid utilities have taken small steps toward implementing

microgrids. Incumbent utilities are still developing a business case for the recovery of costs

associated with establishing (a) “microgrid-readiness” and (b) a tariff structure for the electric service

microgrids provide. One of the arguments against incumbent utility microgrid development is the

potential ratepayer cost impact due to the need to upgrade and retrofit the existing distribution grid to

allow for high DG and energy storage levels. There is no clear regulatory directive to develop

microgrids. There may be other regulatory barriers, such as interconnect rules.

Another barrier may be the close integration, enabled by microgrids, of electricity supply and thermal

energy supply that natural gas presently provides. Microgrids with DG high levels can make use of

small-scale CHP technology (“micro-CHP”) to deliver both electricity and heating or cooling

services for buildings. However, presently the electric distribution grid and the natural gas

distribution grid are entirely distinct entities, with entirely distinct regulatory structures and metering

and billing systems.

A third barrier may be the lack of a third-party electricity supplier than can address an integrated

microgrid-based electrical/thermal/transportation energy supply.

There are also problems with developing a tariff and rate structure for microgrids that would

(a) enable the distribution operator to recover costs and (b) allow a retail supply of microgrid-based

generation and storage services. Without a retail electricity market, using wholesale-connected DG as

part of a utility supply does not necessarily allow microgrid customers to enjoy the economic

benefits of optimized local DG. A new tariff would have to be developed that would allow microgrid

customers to be treated differently from a rate standpoint than the standard bundled utility customer.

This tariff and rate structure will have to be integrated with other policy goals for real-time pricing,

as well as accounting for revenue streams potentially created by microgrid operations.

9. “Advanced Microgrid” Considerations for Systems

9.1 Approaches to Deploying Microgrid Applications

Microgrids integrated with renewable energy sources such as solar and wind can enable many new

applications for the renewables. Using renewable energy usually requires energy storage or spinning

reserve to manage power intermittency. Microgrids also use other sources, such as reciprocating-

engine-driven generators, turbines, fuel cells, micro-hydro generators, and energy storage from a

wide variety of methods.

Early microgrid installations have successfully provided power for essential loads where continuous

power for loads is absolutely necessary. Those early microgrid installations successfully met design

goals, but opportunities and challenges still exist for improving the economics, communication, and

overall marketability. The microgrid installation driver is usually power reliability and consistency to

critical loads, but a few designs are being driven by system-owner economics.

Confidential working paper – permission required for quotations.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Advanced microgrids will provide new functionalities and features that will focus on the reliability of

continuous power to loads, optimization for economics, or both. Security and safety will be

necessary considerations for new designs. Advanced microgrids will provide the ability to perform

value-added functionalities for the system owner and the interconnected electric utility.

9.2 Today’s Microgrid Installations

Three examples of installed and successful microgrids are presented in this section. The drivers for

the installations were reliability of power with security, economics, and reliability with load-

shedding priorities. The first example is the Smart Power Infrastructure Demonstration for Energy

Reliability and Security (SPIDERS) microgrid now operating at two military bases. The goal for

SPIDERS microgrid technology is to provide secure control of on-base generation.

The first SPIDERS microgrid was implemented at Joint Base Pearl Harbor Hickam in Honolulu, and

took advantage of several existing generation assets, including a 146 kW PV power system, and up to

50 kW of wind power. The second installation, at Fort Carson, is much larger and more complex; it

integrates 2 MW of existing solar power, several large diesel generators, and electric vehicles. Large-

scale electric energy storage is also implemented to ensure microgrid stability and to reduce PV

intermittency effects on the system. Advanced microgrids will meet the needs of a wide range of

applications in commercial, industrial, and institutional settings. Larger advanced microgrid

applications will include communities ranging from neighborhoods to small towns. Another largely

untapped application is the “off-grid” area of the world where one billion-plus people live without

regular access to electricity. These “off-grid” areas are currently served (if at all) by diesel generators

or similar small-scale electricity generating equipment. The driver for these systems was reliability of

power to existing loads with additional security that required two-way communications.

A second example of a successful reliability driven microgrid is the White Oak Microgrid installed at

the White Oak Federal Research Center in Silver Spring, Md. The microgrid system designed by

Honeywell ensured that critical operations such as research labs, global data centers, and

communications networks would be able to stay online and function despite conditions around White

Oak, the new headquarters of the U.S. Food and Drug Administration.

The system is a net exporter

of power to the local utility via integrated renewable PV and local electricity generation that supports

the microgrid. It has had an uptime of greater than 99.999% since installation, providing power to

critical loads with some load shedding. The system has automatically islanded more than 70 times in

the last 2.5 years and has never been interrupted due to weather disturbances.

The third example is a microgrid installed with an economics driver—the Princeton Microgrid,

installed on the Princeton University Campus in New Jersey. It has real-time cost reduction controls

and is providing the campus with energy cost savings.

During Hurricane Sandy, Princeton was able

to switch off the grid and power part of the campus with about 11 MW of local generation, according

Sandia National Laboratories, “SPIDERS microgrid project secures military installations,” Sandia Labs News

Release, https://share.sandia.gov/news/resources/news_releases/spiders/, February 22, 2012.

http://www.honeywellnow.com/2011/09/28/honeywell-provides-energy-security-to-help-fda-headquarters-weather-

recent-earthquake-and-hurricane/#ixzz2kYCmMOzJ.

http://www.technologyreview.com/view/507106/microgrids-keep-power-flowing-through-sandy-outages/.

to a report in the Daily Princetonian. The system provides smart capabilities such as automatic load

shedding and black start in the islanded mode.

These examples show proof of concept and point to an advanced microgrid’s overall advantages. The

new structure will provide more viable platforms for large entities to reduce energy cost, improve

grid reliability, and even generate revenue through energy sales during peak demand periods.

Additionally, advanced microgrids will efficiently and effectively provide “off-grid” regions with

regular access to electricity as well as “keep the lights on” for critical applications in times of crisis.

Figure 11 depicts the many opportunities for advanced microgrid systems interconnecting with a

myriad of energy sources and loads that may be critical loads or that provide a balance for the overall

electrical grid or for stand-alone applications.

Figure 11. Depiction of possible energy sources and interconnects for microgrids.

10. Standards and Codes for Advanced Microgrids

U.S. interconnection standards and requirements for DG are currently dominated by the family of

IEEE1547 standards, recommended practices, and guides.

These documents have 5-year effective

lifetimes when published before 2012, but now have 10-year lifetimes. Amendments and corrections

can be balloted within the 10-year period and revisions can be partial or complete. The documents

are updated through volunteer efforts from stakeholders that serve on Standards Coordinating

Committee 21 (SCC 21). Efforts are now underway to update several of the documents to keep up

with the evolving needs to interconnect DR and microgrids with smart grids labeled as EPSs (electric

Basso, Thomas S., Member, IEEE, and DeBlasio, Richard, Senior Member, IEEE, “IEEE 1547 Series of Standards:

Interconnection Issues,” IEEE Transactions on Power Electronics, 19(5), September 2004.

Sandia National Laboratories

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

power systems). The IEEE1547 process is an important and critical effort in that the Energy Policy

Act of 2005 states: “ADOPTION OF STANDARDS.—Section 111(d) of the Public Utility Regulatory

Policies Act of 1978 (16 U.S.C. 2621(d)) is amended by adding at the end the following…”

10.1 Interconnection

Each electric utility shall make available, upon request, interconnection service to any consumer that

the electric utility serves. For purposes of this paragraph, the term ‘interconnection service’ means

service to an electric energy consumer under which an on-site generating facility on the consumer’s

premises shall be connected to the local distribution facilities. Interconnection services shall be

offered based upon the standards developed by the IEEE. The IEEE 1547 for Interconnecting DRs

with EPSs may be amended from time to time. In addition, agreements and procedures shall be

established whereby the services are offered shall promote current best practices of interconnection

for DG, including but not limited to practices stipulated in model codes adopted by associations of

state regulatory agencies. All such agreements and procedures shall be just and reasonable, and not

unduly discriminatory or preferential.

Table 3 lists the IEEE standards and the titles with most applying to interconnected microgrids. Most

of these standards are being revised or will need revisions as the advanced microgrids and

interconnects with the smart grid become reality.

A new IEEE 1547a is a temporary amendment for IEEE 1547 and was on a fast track to support the

exceptional growth of DR and eventually advanced microgrid systems.

It was approved in

December 2013. The focus of the IEEE 1547a Amendment is limited to establishing updates to

voltage regulation, response to area EPS abnormal conditions of voltage and frequency. Other

changes to IEEE 1547 may be made if deemed absolutely necessary in response to the updates that

are established under preceding topics of the amendment. The approval of this new amendment

provides the critical pathway for interconnectivity of microgrids with new smart grid functionalities

such as VAr support and low voltage ride-through.

Also for microgrid systems the recent acceptance of IEEE 1547.4 for design, operation and

integration of DR islanded systems now provides interconnect requirements for microgrids,

renewable energy providers and distributed generation.

“P1547a - IEEE Draft Standard for Interconnecting Distributed Resources with Electric Power Systems -

Amendment 1,” http://standards.ieee.org/develop/project/1547a.html.

“IEEE1547.4 Guide for Design, Operation, and Integration of Distributed Resource Island Systems with Electric

Power Systems,” http://grouper.ieee.org/groups/scc21/1547.4/1547.4_index.html.

Table 3. Advanced Microgrid-Relevant IEEE Standards Description and Status

IEEE Standard

Title and short description

1547-2003

IEEE Standard for Interconnecting Distributed Resources with Electric Power Sources

1547.4-2011

IEEE1547.4 Guide for Design, Operation, and Integration of Distributed Resource Islanded Systems

with Electric Power Systems

1547.7

IEEE P1547.7 Draft Guide to Conducting Distribution Impact Studies for Distributed Resource

Interconnection (Approved Sept 2013)

P1547.8

IEEE P1547.8/D5.0 Draft Recommended Practice for Establishing Methods and Procedures that

Provide Supplemental Support for Implementation Strategies for Expanded Use of IEEE 1547

(Clause 8- Recommended Practice for DR Islanded Systems) Status: Ballot ready draft due 2Q2014

P1547a –

Amendment 1

IEEE1547a Standard for Interconnecting Distributed Resources with Electric Power Sources –

Amendment 1 (The amendment limited to address three topics for change 1) voltage regulation, 2)

voltage ride-through, and 3) frequency ride-through.) Status: P1547a/D2 ballot achieved 91 %

affirmation; recirculation Dec 2013)

1547 Revision

PAR December 2013; Working group Jan 2014

Other standards that are likely to apply to advanced microgrid systems and their components are

being developed. The IEEE 2030 Smart Grid Interoperability Series of Standards is one example.

Developing this set of standards stems from the Energy Independence and Security Act of 2007. It

calls for developing protocols and standards to increase smart-grid equipment/system flexibility of

use. Under Section 1305 of the act, this interoperability framework “shall be flexible, uniform, and

technology neutral” and “align policy, business, and technology approaches in a manner that would

enable all electrical resources, including demand-side resources, to contribute to an efficient, reliable

electricity network.” Other standards, led by the IEEE 2030 series as a framework are moving

forward at this time.

Figure 12. The IEEE 2030 suite of standards and guides for smart grids.

“2030 Smart Grid Interoperability Series of Standards,” http://grouper.ieee.org/groups/scc21/dr_shared/2030/.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Microgrids will often be connected to or in close proximity to utility substations. DNP3 (distributed

network protocol) is a set of communications protocols used between components in process-

automation systems.

Its main use is in utilities such as electricity and water companies. Usage in

other industries is not common. It was developed for communications between various types of data

acquisition and control equipment. It plays a crucial role in SCADA systems, where it is used by

SCADA master stations (aka control centers), remote terminal units, and intelligent electronic

devices. It is primarily used for communications between a master station and remote terminal units

or intelligent electronic devices. The inter-control center communications protocol (a part of

IEC 60870-6) is used for inter-master station communications.

The DNP3 protocol was designed to be very reliable, but it was not designed to be secure from

attacks by hackers and other malevolent forces that could potentially wish to disrupt control systems

to disable critical infrastructure. Because smart-grid applications generally assume access by third

parties to the same physical networks and underlying infrastructure of the grid, much work has been

done to add secure authentication features to the DNP3 protocol. The DNP3 protocol is now

compliant with IEC 62351-5.

10.2 Microcontrollers

The reason for establishing a standard for microgrid controllers is to enable interoperability of

components through cohesive and platform-independent interfaces. This approach will allow for

flexibility and customization of components and control algorithms to be deployed without

sacrificing “plug-and-play” or limiting potential functionality. This is important for both the μEMS

as well as for achieving transient performance, system stability, and regulation requirements

(voltage, current, etc.). Technical challenges associated with these controllers will include

computational power necessary to react to the stochastic nature of some renewable sources and to

perform more advanced control and optimization calculations.

Communications and interfaces to these microcontrollers will drive a hardened security approach.

This becomes more complex as Internet-type interfaces are introduced requiring a secure cyber

connection.

Establishing standards that define the appropriate security level and microcontroller testing will need

to consider the risks associated with particular microgrids and the impact of a compromised system.

These considerations should be weighed against the cost of implementing the necessary levels of

security. Further, software (commercial or custom) and components should be interoperable and with

interfaces that comply with functional standards.

“Overview of the DNP3 Protocol,” http://www.dnp.org/pages/aboutdefault.aspx.

10.3 Code Requirements

Codes are typically requirements for installing components and systems and are designed for

personnel safety and fire prevention. Microgrids installed in the United States will be subject to some

of the requirements of national, state, and local codes. Codes that may apply include:

 National Electrical Code, NFPA 70 (with the applicable edition determined by local adoption or

legislation)

 National Electrical Safety Code, American National Standards Institute (ANSI) Standard C2

 State and local electrical codes

 International Building Code

10.4 The NIST Interoperability Framework

Although NIST does not write standards, it has been mandated to coordinate and collaborate on

standards for interoperability or DG with the evolving smart grid. NIST organized a number of

groups and events to achieve the goal of an interoperable smart grid. These groups include SGIP (the

Smart Grid Interoperability Panel) along with its committees and working groups. Outputs include

the NIST Framework and Roadmap for Smart Grid Interoperability Standards.

Guidelines for

Smart Grid Cyber Security, NIST Interagency Report 7628 (Aug. 2010) are also available to the

public. Various documents related to new or modified standards are produced by Priority Action Plan

working groups. These materials along with descriptions of the various groups, their memberships,

tasks, and timelines can all be accessed at http://collaborate.nist.gov/twiki-

sggrid/bin/view/SmartGrid/WebHome.

10.5 Other Standards

Other standards will apply to microgrid systems but are too numerous to discuss in this paper.

Examples of other standards include but are not limited to:

 IEEE and ANSI standards for batteries and battery installations

 ANSI and American Society for Testing and Materials standards for construction and protection

from elements like surges

 IEEE and ANSI standards for the numerous components utilized in microgrid systems

 International standards from the IEC

 Underwriters Laboratories and ANSI standards for certification for safety of and performance of

components

10.6 Special Cases

Special cases for requirements for installations and operations will continue to apply in localities

where no local codes or national codes applied due to local circumstances or the requirements of

local utilities, or where environment or operations circumstances dictate modifications or different

standards. Examples include special state exemptions for localities such as Hawaiian Islands or parts

of Alaska.

“National Electrical Code, NFPA70,” Published by the National Fire Protection Association, Batterymarch, MA.

National Electrical Safety Code, 2012 Edition, Published by the NFPA, Batterymarch, MA.

http://www.nist.gov/public_affairs/releases/upload/smartgrid_interoperability_final.pdf.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

10.7 Smart Grid Interoperability Panel

The SGIP is a public private partnership, supported by NIST. Its primary responsibility is to identify

standards and gaps in standards with respect to interoperability. FERC has spoken out on the critical

need for interoperability within the energy grid and has called SGIP “the best vehicle for developing

smart-grid interoperability standards.” SGIP has established committees and working groups to

address smart grid and interoperability issues.

The Distributed Renewables, Generators and Storage

Domain Expert Working Group, in particular Subgroup C - Microgrids and Hierarchical Distributed

Control, is proactively working on issues related to advanced microgrids.

11. Summary

Advanced microgrids will indisputably become a significant player in maintaining and improving the

quality, reliability, and resilience of the nation’s electricity grid in the future. Several of today’s

microgrids are already providing some of the services, features, and functionalities that will be

required of an advanced microgrid. New advanced microgrids will have interoperability capabilities

in widely varying degrees but interoperability will be necessary as the electricity grid gains

intelligence. The drivers for advanced microgrids will be more complex that today’s reliability and

economic drivers for microgrid installations, but the two the two key drivers will remain either for

the owner or the utility infrastructure. Reliability, resilience, longevity, electricity grid support,

critical-load power will remain the most important metrics. The number of variables to be addressed

in the near future is large but manageable and affordable. There will likely standard advanced

microgrid configurations that bracket interoperability protocol, communications optimization, and

prioritization but custom designs will likely prevail for several years. There are many methods for

employing communications in advanced microgrids and likely new methods will evolve. An

advanced microgrid development program tied with learning from installations will sort out the

winners and losers. It is already clear that two-way communications coupled with internal

communications and some microgrid system autonomy will reduce the communications complexity.

New and evolving standards and codes are emerging today but there is much to be addressed with

solutions that do not lock in or lock out sectors that can successfully transform systems into advanced

microgrids. This paper provides a compilation of today’s hardware, materials, and methodologies

along with goals and visions for advanced microgrids. The challenges and opportunities are

presented; all that remains is applying the ingenuity and expertise to bring advanced microgrids to

future installations that are ready for even more improvements for the owners and the interoperable

utilities.

12. References

Office of Electricity Delivery and Energy Reliability Smart Grid R&D Program, “DOE Microgrid

Workshop Report,” http://energy.gov/oe/downloads/microgrid-workshop-report-august-2011, Aug 2011.

Office of Electricity Delivery and Energy Reliability Smart Grid R&D Program, “DOE Microgrid

Workshop Report,” http://energy.gov/oe/downloads/2012-doe-microgrid-workshop-summary-report-

september-2012, Sep 2012.

http://www.sgip.org/about_us/#sthash.JwWXxok5.dpbs.

Executive Office of the President, “Economic Benefits of Increasing Electric Grid Resilience to Weather

Outages,” http://energy.gov/oe/articles/white-house-council-economic-advisers-and-energy-department-

release-new-report , Aug 2013.

Smith, M. and D. Ton, “Key Connections: The U.S. Department of Energy’s Microgrid Initiative,” IEEE

Power and Energy Magazine, 11(4), Jul 2013.

Energy Policy Act of 2005, Public Law 109–58—Aug. 8, 2005, 109th Congress.

The Energy Independence and Security Act of 2007,

http://www1.eere.energy.gov/femp/regulations/eisa.html

SGIP webpage for applicable Smart Grid Interconnections, http://www.sgip.org/#sthash.6Gcyft6W.dpbs

Asmus, P., (Contributor, Chart from Pike Research), “Moving Microgrids into the Mainstream,”

http://www.forbes.com/sites/pikeresearch/2012/10/17/moving-microgrids-into-the-mainstream/

U.S. Energy Information Administration, “Smart Grid Legislative and Regulatory Policies and Case

Studies,” Dec 2011.

10.

“Multi-Year Program Plan (MYPP) 2010–2014,” Sep 2012 Update.

11.

Lasseter, R., A. Akhil, C. Marnay, J. Stephens, J. Dagle, R. Guttromson, S. Meliopoulous, R. Yinger, and

J. Eto, “Integration of Distributed Energy Resources: The CERTS Microgrid Concept,” Lawrence

Berkeley National Laboratory, http://escholarship.org/uc/item/9w88z7z1, Apr 01, 2002.

12.

http://grouper.ieee.org/groups/scc21/dr_shared/2030/

13.

Milliron M., L. Spiegel, and J. Franks, “Public Interest Energy Research 2011 Annual Report,” California

Energy Commission, Energy Research and Development Division, Publication# CEC‐ 500‐ 2012‐ 003‐

CMF, 2012.

14.

“Trends in Microgrid Control,” IEEE PES paper to be released Jul 2014.

15.

Hampson, A., T. Bourgeois, G. Dillingham, and I. Panzarella, “Combined Heat and Power: Enabling

Resilient Energy Infrastructure For Critical Facilities,” http://www1.eere.energy.gov/

manufacturing/distributedenergy/pdfs/chp_critical_facilities.pdf, ORNL/TM-2013/100, Mar 2013.

16.

Hionis, A. and S. Ng, “Case Study: Advanced Energy PV Inverters Ride-Through PG&E Low Voltage

Events,” http://www.google.com/#fp=492a54485f563ccb&psj=1&q=PG%26E+Case+Study+

260-01, 2012.

17.

Smart Grid Reference Architecture, CEN-CENELEC-ETSI Smart Grid Coordination Group, November

2012.

18.

Microgrid Control, Dr. Geza Joos, Oct 2013.

19.

Bower, W., “Solar Energy Grid Integration Systems (SEGIS)-Adding Functionality While Maintaining

Reliability and Economics,” SPIE Conference; San Diego, CA; Aug 22, 2011.

20.

BACnet® is a registered trademark of American Society of Heating, Refrigerating and Air-Conditioning

Engineers (ASHRAE). The website is dedicated to providing the latest information on BACnet – “A Data

Communication Protocol for Building Automation and Control Networks,” http://www.bacnet.org/

21.

Black and Veatch, “2011 Strategic Directions Survey Results,” http://bv.com/docs/reports-studies/2011-

Electric-Utility-Survey-Results.pdf, 2011.

22.

Federal Energy Regulatory Commission, “Small Generator Interconnection Agreements and Procedures,

Notice of Proposed Rulemaking,” 142 FERC 61,049. Jan 17, 2013.

23.

McDermott K. “The Regulatory Dilemma: Getting Over the Fear of Price,” The Electricity Journal, 25(9),

pp 6–13, Nov 2012, http://dx.doi.org/10.1016/j.tej.2012.10.011.

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

24.

Kelly, J., G. Rouse, and R. Nechas, “Illinois Electricity System Guiding Principles and Policy

Framework,” Galvin Electricity Initiative, Jul 2010.

25.

Federal Energy Regulatory Commission, “Notice of Proposed Rulemaking: Third-Party Provision of

Ancillary Services; Accounting and Financial Reporting for New Electric Storage Technologies,” 139

FERC 61,245, Jun 22, 2012.

26.

Sandia National Laboratories, “SPIDERS microgrid project secures military installations,” Sandia News

Release, https://share.sandia.gov/news/resources/news_releases/spiders/, Feb 22, 2012.

27.

Morren, J., S.W. de Haan, W.L. Kling, and J.A. Ferreira, “Wind Turbines Emulating Inertia and

Supporting Primary Frequency Control,” IEEE Transactions on Power Systems, 21(1), 433–4, 2006.

28.

Morrison, J. A. “The Clash of Industry Visions,” The Electricity Journal, 18(1), 14–30, 2005.

29.

Chu, L.Y. and D.E. Sappington, “Motivating Energy Suppliers to Promote Energy Conservation,” Journal

of Regulatory Economics, Jan 19, 2013.

30.

“CHP Kept Schools, Hospitals Running Amid Hurricane Sandy,” http://www.ase.org/efficiencynews/chp-

kept-schools-hospitals-running-amid-hurricane-sandy, Dec 11, 2012.

31.

Hayashi, P.M., J. Yeoung-Jia Goo, and W.C. Chamberlain, “Vertical Economies: The Case of U. S.

Electric Utility Industry, 1983-87,” Southern Economic Journal, 63(3), 710–725, Jan 1997.

32.

HOMER – The Optimization Model for Distributed Power, NREL, http://www.nrel.gov/homer/.

33.

Basso, T.S. (Member, IEEE) and R. DeBlasio (Senior Member, IEEE), “2030 Smart Grid Interoperability

Series of Standards,” IEEE 1547 Series of Standards: Interconnection Issues, IEEE Transactions on Power

Electronics, 19(5), Sep 2004.

34.

IEEE519-1992, “IEEE Recommended Practices and Requirements for Harmonic Control in Electrical

Power Systems,” Persistent Link, http://ieeexplore.ieee.org/servlet/opac?punumber=2227.

35.

P1547a, “IEEE Draft Standard for Interconnecting Distributed Resources with Electric Power Systems -

Amendment 1,” http://standards.ieee.org/develop/project/1547a.html.

36.

IEEE 1547.4, “Guide for Design, Operation, and Integration of Distributed Resource Island Systems with

Electric Power Systems,” http://grouper.ieee.org/groups/scc21/1547.4/1547.4_index.html

37.

2014 National Electrical Code, NFPA70, Published by the National Fire Protection Association,

Batterymarch, MA., Jan 2014

38.

IEEE P1547.7, “Draft Guide to Conducting Distribution Impact Studies for Distributed Resource

Interconnection,” (First ballot approved Sep 2013 – Now recirculating)

39.

IEEE P1547.8/D5.0, “Draft Recommended Practice for Establishing Methods and Procedures that Provide

Supplemental Support for Implementation Strategies for Expanded Use of IEEE Standard 1547,” (Clause

8- Recommended Practice for DR Islanded Systems )(Ballot ready draft due 4Q2013)

40.

UL1741, “The Standard for Inverters, Converters and Controllers for Use In Independent Power Systems,”

Underwriters Laboratories, Northbrook, IL, 2011

41.

IEC 61850, “Communication Networks and Systems In Substations,” Technical Committee 57,

International Electrotechnical Commission, Related parts in progress.

42.

“CPUC Rule 21 Activities,” http://www.cpuc.ca.gov/PUC/energy/Procurement/LTPP/rule21.htm,

Interconnectivity recommendations and requirements under development, Nov 2013.

Distribution

Brookhaven National Laboratory

Attn: M. Villaran

P.O. Box 5000 - Building 130

Upton, NY 11973-5000

California Public Utilities Commission

Attn: J. Erickson

505 Van Ness Avenue

San Francisco, CA 94102

Department of Energy

Office of Electricity Delivery & Energy Reliability

Attn: Dan Ton

1000 Independence Ave, SW

MS OE 10

Washington, D.C., 20585

Electric Power Research Institute

Attn: M. Wakefield

942 Corridor Park Blvd.

Knoxville, Tennessee 37932

Electric Power Research Institute

Attn: T. Key

942 Corridor Park Blvd.

Knoxville, Tennessee 37932

Honeywell

Attn: T. Glennon

1985 Douglas Drive North

Golden Valley, MN 55422-3992

Institut de recherche d'Hydro-Québec

Attn: C. Abbey

1800, boul. Lionel-Boulet

Varennes (Quebec) J3X 151

CANADA

Lawrence Berkley National Laboratory

Attn: C. Marnay

Berkeley Lab MS 90R2002

1 Cyclotron Rd

Berkeley, CA 94720

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535

Lawrence Berkeley National Laboratory

Attn: M. Stadler

1 Cyclotron Road

Mailstop 90R1121

Berkeley, CA 94720

Massachusetts Department of Public Utilities

Attn: Dhruv Bhatnagar

Electric Power Division

1 South Station

Boston, MA 02110

McGill University

Attn: G. Joos

McConnell Engineering Building, Rm 641

3480 University St

Montreal, QC H3A 0E9

Canada

National Grid

Attn: B. Enayati

40 Sylvan Rd

Waltham, MA 02451

National Institute of Standards

Attn: A. Hefner

Bldg. 225, Rm. B-314

100 Bureau Dr.

Gaithersburg MD 20899

National Renewable Energy Laboratory

Attn: T. Basso

15013 Denver W Pkwy

Golden, CO 80401

National Technical University of Athens

Attn: N. Hatziargyriou

School of Electrical & Computer Engineering

9, Iroon Polytechniou Str.

Athens 157 80

Greece

New Energy Industrial Development Organization

Attn: S. Morozumi

MUZA Kawasaki Central Tower

1310 Omiya-cho, Saiwai-ku

Kawasaki, Kanagawa 212-8554

Japan

Oak Ridge National Laboratory

Attn: T. King

1 Bethel Valley Rd.

Oak Ridge, TN 37830

Princeton University

Attn: T. Borer

Engineering and Campus Energy

MacMillan Building, Elm Drive

Princeton, NJ 08543-2158

Reilly Associates

Attn: J. Reilly

PO Box 838

Red Bank, NJ 07701

University of California, San Diego

Attn: C. Wells

3391 Lebon Drive, #201

San Diego, CA 92122

University of Waterloo

Attn: C. Cañizares

E&CE Department Office EIT-4168 200

University Avenue West

Waterloo, ON

Canada N2L 3G1

MS0509 Steven F. Glover Org. 10653

MS1140 Ross Guttromson Org. 06113

MS1188 Jason E. Stamp Org. 06114

MS0899 Technical Library 9536 (electronic copy)

The Advanced Microgrid: Integration and Interoperability

SAND2014-1535