oEPA

State and Local Climate
and Energy Program

State Energy and Environment
Guide to Action:

Interconnection and Net Metering

2022


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Interconnection and Net Metering

Table of Contents

Preface and Acknowledgments		 ii

Policy Description and Benefits...............							1

Summary	1

Benefits	2

Electricity System Benefits	2

Customer Benefits	3

Economic Benefits	3

Environmental Benefits	3

Quantifying and Communicating the Benefits	3

Current Regulatory Landscape	5

Overview	5

A Changing Landscape for State Net Metering	6

Updating and Streamlining Interconnection Processes for DERs	8

Hosting Capacity Analysis	9

Designing Effective Interconnection Standards and Net Metering Rules	10

Participants		 10

Typical Specifications for Interconnection and Net Metering	12

Specifications for Interconnection	12

Specifications for Net Metering	14

Interaction with Federal Policies						 16

Interaction with State Policies				 17

implementation and Evaluation																												17

Implementation	17

Evaluation	18

Action Steps for States	18

States with Existing Interconnection and Net Metering Policies								 19

States without Existing Interconnection and Net Metering Policies 											 19

State Examples	20

Massachusetts	20

Virginia	21

California	22

Utah 														23

Information Resources	24

Research Reports and Other Net Metering Resources	24

Federal Resources	24

National Standards Organizations	25

Examples of Interconnection Standards	25

References	25

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Preface and Acknowledgments

The U.S. Environmental Protection Agency (EPA) State Energy and Environment Guide to Action offers real-
world best practices to help states design and implement policies that reduce emissions associated with
electricity generation and energy consumption. First published in 2006 and then updated in 2015, the Guide is
a longstanding EPA resource designed to help state officials draw insights from other states' policy innovations
and implementation experiences to help meet their own state's climate, environment, energy, and equity
goals.

As part of the 2022 update, each chapter reflects significant state regulatory and policy developments since
the 2015 publication. Guide chapters provide descriptions and definitions of each featured policy; explain how
the policy delivers energy, climate, health, and equity benefits; highlight how states have approached key
design and implementation issues; and share best practices based on state experiences.

Unlike earlier Guide editions, which were released as a complete set of chapters comprising a single document,
the 2022 update is being released in phases of collected chapters. This chapter is one of seven addressing
state-level utility policies that support clean energy and energy efficiency:

•	Overview of Electric Utility Polices

•	Electricity Resource Planning and Procurement

•	Electric Utility Regulatory Frameworks and Financial Incentives

•	Interconnection and Net Metering

•	Customer Rates and Data Access

•	Maximizing Grid Investments

•	Energy Efficiency Programs and Resource Standards

Guide chapters are available online on the Guide to Action webpage.

All Guide chapters were developed by the Climate Protection Partnership Division's State and Local Climate
and Energy Program within EPA's Office of Atmospheric Programs. Phil Assmus managed the overall update of
the Guide and provided content and editorial support for all chapters. David Tancabel served as the chapter
lead for six utility policy chapters, and Cassandra Kubes led a crosscutting effort to address equity issues across
all Guide chapters. Maggie Molina provided technical review and editorial support across all chapters and led
the development of the energy efficiency chapter. We thank additional EPA staff, namely Erica Bollerud, Joe
Bryson, Beth Conlin, James Critchfield, Risa Edelman, Maureen McNamara, and Neeharika Naik-Dhungel, who
provided guidance for one or more chapter's initial development, early draft review, or final content.

We thank the following experts who commented on draft versions of the Guide chapters. Their contributions
helped to revise and improve one or more Guide chapters but do not imply endorsement of the final content:
Miles Keogh of the National Association of Clean Air Agencies, Lisa Schwartz and Ian Hoffman of Lawrence
Berkeley National Laboratory, Ben Kujala of the Northwest Power and Conservation Council, Jeff Loiter of the
National Regulatory Research Institute, Forest Bradley-Wright of the Southern Alliance for Clean Energy, Greg
Dierkers of the U.S. Department of Energy, Commissioner Abigail Anthony of the Rhode Island Public Utilities
Commission, Doug Scott of the Great Plains Institute, Weston Berg and Rachel Gold of the American Council
for an Energy-Efficient Economy, Cara Goldenberg of the Rocky Mountain Institute, Lon Huber of Duke Energy,
Radina Valova of the Interstate Renewable Energy Council, Christopher Villarreal of Plugged In Strategies,

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Rodney Sobin of the National Association of State Energy Officials, Alex Bond of the Edison Electric Institute,
Julie Michals of E4TheFuture, Dan Lauf of the National Governors Association, and Cyrus Bhedwar of the
Southeast Energy Efficiency Alliance.

We also thank the many state officials and regulatory staff who reviewed state-specific policy examples
highlighted in each of the chapters.

A multidisciplinary team of energy and environmental consultants provided research, analysis, and technical
support for this project. They include: Abt Associates (Rubenka Bandyopadhyay, Juanita Barboa, Heather
Hosterman, Amy Rowland, James Schroll, Elizabeth Shenaut, Christine Teter, and Christina Davies Waldron),
Efficiency for Everyone (Marti Frank), and Regulatory Assistance Project (Jeff Ackermann, David Farnsworth,
Mark LeBel, Richard Sedano, Nancy Seidman, John Shenot, and Jessica Shipley).

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Policy Description and Benefits
Summary

States use interconnection and net metering policies to
integrate customer-sited, distributed energy resources (DERs)
into the electric grid or to encourage greater investment in
these resources. DERs are electric generation, demand
response, or energy storage systems located on the distribution
system, typically close to load, used individually or aggregated to
provide more value. These resources can help meet electricity
needs, reduce emissions, enable customer cost-savings, and
improve energy security and resiliency. Interconnection
standards and net metering rules can support the development
of DERs by providing clear and reasonable requirements for
connecting clean energy systems to the electric utility grid for
both the utility and the customer and by compensating
participants hosting DERs for the electricity they export back to
the grid.

This chapter describes state experience in using interconnection standards and net metering policies to
facilitate or encourage the adoption of DERs, such as rooftop solar photovoltaic (PV), energy storage, and
combined heat and power (CHP). These resources can reduce generation and transmission infrastructure
costs, stimulate economic growth, reduce customer bills, improve outdoor air quality, enhance energy
resiliency, and reduce health impacts from fossil fuel generation. The chapter focuses on state-level actions by
state utility regulators and legislatures. It covers the distinct but complementary components of
interconnection standards and net metering rules and how policy design and implementation can create
incentives, reduce uncertainty, and prevent excessive delays and costs associated with connecting DERs to the
grid. This chapter reviews why net metering policies were initially created and discusses why many states
are studying, updating, adjusting (e.g., increasing program size or reserving program capacity for low-
income customers), or replacing their original programs. The chapter also briefly examines
complementary state and federal policies.

The following are several examples of action steps states use to realize the benefits of DERs:

•	Review existing interconnection standards and net metering rules while considering state priorities and
other state examples.

•	Engage DER stakeholders and gather community input from customers with DER systems and non-
participants.

•	Approach the design of interconnection standards in a way that balances requirements for grid reliability
and safety, flexibility for DER technology, and compensation for DER customers.

•	Make interconnection accessible for a broad range of customers by adopting application processes that
are streamlined for smaller, simpler projects and more robust for larger, more complex projects.

•	Ensure equitable access to DER benefits through net metering by engaging with communities and
providing options such as virtual net metering to allow program participation of community shared solar
for groups of customers.

Interconnection standards are processes
and technical requirements that specify for
electric utilities and customers the system
requirements and procedures to connect
energy projects to the electricity grid.

Net metering, also referred to as net energy
metering (NEM). is a method of compensating
a utility customer that hosts a grid-connected
DER system for the electricity generated at
the customer site that is more than their own
consumption - essentially giving customers
credit for the excess power they send back to
the grid. Depending on the individual state or
utility rules, net excess generation may be
credited to the customer's account or carried
over to the future.

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• Monitor and evaluate net metering and interconnection programs to inform policy adjustments as

economic costs, technology, and grid needs evolve, and in response to participation levels and customer

•	When reviewing established net metering programs, study options for ensuring costs and benefits are
distributed fairly among participants and non-participants, such as through value-of-solar studies,

•	As DER penetration increases, verify that compensation for net metering program participants reflects
system needs.

These and other state practices are discussed in the Designing Effective Interconnection Standards and Net
Metering Rules section and in the Implementation and Evaluation section. This chapter concludes by
highlighting state policy examples from Massachusetts, Virginia, California, and Utah.

Interconnection standards and net metering rules are inextricably linked, and together they can spur DER
adoption, providing benefits to the energy system, customers, and society. This section summarizes many but
not all of these benefits. For more details on DER benefits, the National Standard Practice Manual for Benefit-
Cost Analysis of Distributed Energy Resources (NSPM for DERs) catalogs the many types of potential benefits of
DERs and presents principles and guidelines for analyzing their cost-effectiveness (NESP 2020).

Electricity System Benefits

Interconnection and net metering policies have the potential to encourage customer DER adoption. DER
benefits vary by the time of day the resource is deployed and its location on the distribution system. With
sufficient adoption, grid planning, and integration, DER deployment can reduce demand for, and costs
associated with, centralized fossil-fired power generation and new generation capacity, fossil fuel supply
resource extraction and delivery, and the construction of new transmission and distribution infrastructure.

For a perspective on the scale of solar DER adoption levels, one example is small-scale solar PV relative to U.S.
installed capacity and generation. In 2021, small-scale solar PV accounted for 30.4 gigawatts (GW) or 11
percent of summer renewable energy capacity and 5 percent of the nation's total renewable energy
generation (EIA 2021a). In California, a state with an active net metering program, small-scale, customer-
owned (behind-the-meter) solar generation is forecasted to increase by 260 percent from 15,800 to 41,200
gigawatt-hours (GWh) from 2019 to 2030, and customer-owned energy storage capacity is forecasted to
increase 770 percent from 2019, reaching 2.6 GW by 2030 (CPUC 2021b).

DERs can benefit the electricity system by reducing the amount of energy and peak capacity a utility needs to
purchase. When aggregated, some DER technologies can provide ancillary services and help grid operators
balance supply and demand in real time. DER investments that help meet capacity needs reduce the need for
and associated costs of large-scale investment in new fossil fuel power generation units. Distribution system
planning (DSP)1 and energy demand management are ways to ensure that DERs support grid balancing, offset
higher-emission generation, and provide overall benefits. Encouraging DER siting in locations that most benefit
the grid can help maximize DER benefits (AEE 2018).

1 One type of DSP (also called integrated distribution system planning or IDSP) is hosting capacity analysis (HCA). For more on I DSP
and HCA, refer to the Maximizing Grid Investments chapter in the Guide.

needs.

Benefits

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Customer Benefits

For the residential or commercial DER host customer, DERs can provide a source of recurring revenue or
electricity cost-savings, depending on usage, rate design, and government tax incentives. In many cases, the
upfront financial costs to the host customer are offset by the ongoing financial benefits of recurring revenue or
electricity credit generated by the DER. DERs can be used by commercial or industrial host customers to
manage their peak demand and reduce the demand charge owed to the utility. To the extent aggregated and
flexible DER support grid balancing and reduce utility capacity needs, they lower utility costs and ultimately
benefit all ratepayers.

Economic Benefits

DERs provide economic benefits associated with local job creation, which has ripple effects on economic
development in a community. DER systems such as rooftop PV and energy storage spur local job creation in
energy system design and installation, and some DERs are manufactured in the United States. By the end of
2020, over 231,000 U.S. workers had a job primarily dedicated to solar energy, and another 86,000 U.S.
employees spent some (less than half) of their working hours on solar projects (NREL 2021c). Residential PV
accounted for over half of the solar installation jobs in 2020. Within the solar workforce, union members,
veterans, and non-African American minorities have higher representation than the national average (NREL
2021c).

Environmental Benefits

Environmental benefits from DERs vary with the type of technology, fuel, timing, and location of DER
deployment; but environmental benefits typically include pollution reduction, improved outdoor air and water
quality, and reduced environmental health impacts associated with fossil fuel power generation. DERs have
the potential to reduce pollution in communities with environmental justice concerns. Research has shown
that exposures to and health impacts of air pollution from electricity generation is higher for low-income and
Black communities than other demographic groups (Maninder et al. 2019). Moving generation to locations
where load exists can reduce plant operations and the resulting air emissions at the site of a larger central
facility. Policies and programs, including interconnection and net metering, that help to avoid or reduce the
use of fossil fuel energy and criteria air pollutants can benefit public health by reducing incidences of
premature death, asthma attacks, and respiratory and heart disease; avoiding related health costs; and
reducing the number of missed school and workdays due to illnesses.

Quantifying and Communicating the Benefits

Environmental regulators, state energy office officials, consumer advocates, utilities, and utility regulators
(called in some states a public utility commission or public service commission) al! have their own roles in
shaping and implementing interconnection standards and net metering programs. Each group has unique
interest in the impacts of these policies (for more on participants and their roles, refer to the Participants
section in this chapter). To help states and stakeholders analyze and quantify these impacts, EPA has a range of
tools highlighted in the text box.

State air agency staff may focus on how DER adoption and load shifting can reduce air emissions and
contribute to meeting each jurisdiction's air quality goals. State energy and air office staff can use EPA's
AVoided Emissions and geneRation Tool (AVERT) to evaluate the emission impacts of policies that increase the

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participation rate in net metering
programs or other targeted energy
policies. EPA's Co-Benefit Risk
Assessment (COBRA) model can
then be used to evaluate and
quantify the health impacts of these
emissions changes. With these
tools, state environmental
regulators can quickly evaluate the
impacts of one or more policies and
their associated changes to load and
emissions at different temporal
(hourly to annual) and spatial
(county to region) scales.

Each jurisdiction conducts cost
benefit assessments for their
programs differently. Understanding
the benefits and how to quantify
those benefits enables stakeholders
to develop, implement, and justify
programs and policies like net
metering. For jurisdictions that
consider or account for health
impacts in their decision-making
processes, EPA's COBRA tool and
health benefits per kilowatt-hour
(BPK) values give health officials,
utilities, and utility regulators the
ability to quantify and monetize the
health benefits from the reduced
operation of fossil fuel generation
that results from DER

interconnection and net metering. Utilities and utility regulators can use the BPK values to incorporate the
public health impacts of power generation into DER value assessments that get included in compensation rates
for excess energy. For example, an analysis of BPK applications from the Regulatory Assistance Project suggests
ways BPK values can inform how a utility sets time varying rates2 and rates to incentivize economic
development (RAP 2021). In addition to tools, EPA offers the detailed resource Quantifying the Multiple
Benefits of Energy Efficiency and Renewable Energy: A Guide for State and Local Governments (EPA 2018).

EPA Environmental Impacts and Health Benefits of Clean Energy
Tools

EPA has a range of free tools available to support states and stakeholders

with analyzing and quantifying the environmental impacts and health benefits

of clean energy, including but not limited to the following:

•	AVoided Emissions and geneRation Tool (AVERT) is a tool designed
to meet the needs of state air quality planners and other interested
stakeholders. Non-experts can use AVERT to evaluate county, state,
and regional emissions displaced at fossil fuel power plants by policies
and programs that support efficiency, clean DER, and utility scale
renewable energy.

•	CO-Benefits Risk Assessment (COBRA) Health Impacts Screening
and Mapping Tool is a tool that helps state and local governments
estimate and map the air quality, human health, and related economic
benefits of clean energy policies and programs at the national, state, and
county levels. Analysts assessing the impacts of changes in rate design
can enter corresponding changes in emissions from the electric utility
sector and use the results from COBRA to inform cost-benefit analyses
and other decision-making processes.

•	Health Benefits Per Kilowatt-Hour (BPK) is a set of values that help
state and local government policymakers and other stakeholders develop
screening-level estimates of the outdoor air quality-related public health
benefits of investments in energy efficiency and other clean DER.

•	Energy Savings and Impacts Scenario Tool (ESIST) is a customizable
and transparent Excel-based planning tool for analyzing the energy
savings and costs from customer-funded energy efficiency programs and
their impacts on emissions, public health, and equity. ESIST enables
users to develop, explore, and share energy efficiency scenarios
between 2010 and 2040.

•	Emissions & Generation Resource Integrated Database (eGRID) is a
comprehensive source of data on environmental characteristics of
electric power plants in the United States. The interactive eGRID
Explorer dashboard offers data, maps, and graphs on electric power
generated, emissions, emission rates, heat input, resource mix, and
more.

•	Quantifying the Multiple Benefits of Energy Efficiency and
Renewable Energy describes methods, tools, and steps analysts can
use to quantify these benefits so that they can compare costs and

2 A time varying rate (TVR) is a rate that varies by the hour the electricity is used to reflect higher costs of providing electricity service
during peak periods in the day. Some states are evaluating or implementing TVRs within their net metering programs. For example,
South Carolina incorporated time-of-use rates in its net-metering successor program (NREL 2021c). Refer to the Customer Rates and
Data Access chapter in the Guide for more information.

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Current Regulatory Landscape

This section first provides an overview of the regulatory landscape for state interconnection standards and net
metering, followed by a discussion of the changing landscape for state net metering policies. This section
describes state efforts to update and streamline interconnection processes for DERs and to improve the
equitable distribution of grid upgrade costs.

Overview

Interconnection standards and net metering rules are developed and overseen by state utility regulators3 or by
the Federal Energy Regulatory Commission (FERC). State regulators typically regulate interconnections that
send excess power back to the local utility (small utility-scale and DER projects), whereas FERC regulates
interconnections where power is exported outside state boundaries.4 State regulators have jurisdiction to
approve the standards used for most interconnections, which are for smaller DER systems that serve the local
utility, such as residential rooftop solar. To initiate new policy or updates, legislators can pass bills or utility
regulators can open a docket.

State regulators have developed interconnection standards that enable customers to connect to a utility's
distribution network. Excessive or expensive interconnection procedures can increase project timelines and
costs, potentially making clean DERs uneconomical.

State legislatures initially created net metering policies as a simple way to compensate early adopters of
solar PV. The rules developed for net metering have allowed PV and other DER systems to receive credit for
electricity generated on site that is exported to the utility grid. In effect, customers that generate and export
more electricity to the grid than they consume, usually on a billing cycle basis, have been able to offset the
cost of future electricity use.

Traditional net metering rules compensated DER owners for their excess electricity at the retail electricity
price, which is much higher than the wholesale price that utilities pay large generators for their electricity.5
When making initial decisions about net metering compensation, many policymakers accepted that the retail
rate was a reasonable approximation for the value of distributed generation. When the number of
participating customers and amount of total energy being credited is relatively small, the potential effect of
retail rates overcompensating for the value of the distributed generation, and consequently affecting customer
rates or utility revenues, is also assumed to be small (NRRI 2019).

Net metering often relies on the use of a single bidirectional utility meter to measure, or "net" out, the use and
flow of electricity to and from the electric grid. Net metering rules have generally placed limitations on eligible
onsite generators, including maximum system size restrictions and the period that customers can roll over net
metering credit into the future (e.g., year-to-year). Many net metering policies are designed with a cap on the
total metered generating capacity that can be installed in the state or utility service area, for example
measured as a percentage of peak demand.

3	A state legislature grants authority to a utility regulator, commission, agency, board, or authority within each state to regulate
electricity rates and reliability. The entity is often named public utility commission (PUC) or public service commission (PSC) but is
referred to as "utility regulator" in the Guide.

4	FERC does not have jur isdiction in Texas, Hawaii, or Alaska (FERC 2018).

5	When DER owners are compensated for excess generation at rates other than the retail rate (e.g., at the wholesale rate), some refer
to the program structure as "net billing" instead of net metering. In this chapter, the term net metering encompasses both
structures, consistent with how some states define it in statute.

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Most states have interconnection standards and a net metering policy in place (NRRI 2019). The DER market
has grown substantially since the first state net metering policies were established. Solar PV efficiency has
increased, and costs for hardware and installation have decreased, improving the overall economics (Kavlak,
McNerneya, and Trancik 2018). From 2010 to 2020, solar PV system costs declined 64 percent for residential
rooftop and 82 percent for commercial rooftop systems (NREL 2021a). State net metering policies, technical
advancements, and declining costs have helped to accelerate the adoption of DERs and the development of
utility-scale solar projects.

The total installed capacity of DER systems enrolled in state net metering programs as of 2020 was at least 28
GW (EIA 2021b). Solar PV accounts for over 90 percent of the net-metered DER capacity (EIA 2020). The
national average customer PV system capacity was approximately 12 kW and the national average customer
wind generator was approximately 36 kW (EIA 2020). The U.S. Energy Information Administration (EIA)
tracks and reports monthly on state electric power data, including net metered capacity, generation, and
number of customers by technology type.

A Changing Landscape for State Net Metering

States, federal officials, stakeholders, and energy system experts are working to understand and potentially
reshape the role of net metering in the changing electricity system landscape.6 As DER penetration rates
increase, many states are in various stages of studying, updating, or replacing their original net metering
policies, with some moving away from a static, retail rate of compensation (NCCETC 2021). Others are
increasing the size of their programs by raising program capacity caps or adjusting their programs by reserving
capacity for low-income customers. Examples of various approaches are presented in the State Examples
section at the end of this chapter.

In some regions, the increased penetration of PV has shifted net demand—the difference between predicted
demand and expected generation from variable sources like PV—in ways that lowers the value of additional
solar generation (NREL 2018a). This happens when there is more solar electricity generation during daylight
hours than needed to meet demand. In some oversupply cases, negative real-time electricity prices can occur
on the wholesale market for some hours of the day (CAISO 2016). Traditional net metering compensation
structures generally do not reflect this widely variable value of PV.

With the growth in number of participants and amount of net metered generation, some stakeholders have
raised concerns. For example, some have asserted that retail rates overcompensate for DER generation at the
expense of ratepayers not participating in the program, and as a result, shift system costs from net metering
participants to non-participants (FERC 2020a). Specifically, some argue that net metering could allow
customers with DERs to reduce their utility bills to a level that they would not equitably contribute to utility
fixed cost recovery (i.e., pay their share of grid infrastructure operation and maintenance costs) (NRRI 2019). If
a utility serves a large number of net metering customers who pay monthly bills too low to cover operation
and maintenance costs, non-participants might pay proportionately more for utility fixed costs (NCSL 2017).

Some state legislatures have requested studies to inform net metering policy proposals. In some states, utility
company requests or preexisting legislative or regulatory requirements trigger the policy reviews. Some
reviews and reforms were prompted by stakeholder concerns that retail rates overcompensate for DER
generation at the expense of ratepayers not participating in the program. Some states saw sufficient interest in
net metering programs that they reached statutory capacity limits, which has sometimes prompted actions to

6 In 2020, U.S. Congress mandated a study for the U.S. Department of Energy on net metering and alternative mechanisms, impacts
on the electricity grid and consumers, and potential contributions of net metering to decarbonization, equity, and resiliency. The
study remains in progress at the time of Guide publication (National Academies of Sciences, Engineering, and Medicine 2022).

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consider new alternatives and successor rates to net metering (NRRI 2019). A 2021 California Public Utility
Commission (CPUC) study found that net metering policies in the state reduced revenue for the utilities, which
resulted in increased rates for non-participating customers (CPUC 2021a; Verdant 2021). However, recent
research finds that the effects of net metering7 on retail electricity rates are likely to remain small or negligible
at anticipated participation levels (LBNL 2017).

Understanding the value of distributed generation allows states to better align customer compensation with
the value that their system provides to the grid. As discussed, the benefits of DERs can vary by time of day and
location on the grid. Some states are opening proceedings or conducting "value of solar" studies to quantify
the benefits and costs of the distributed solar generation to the grid. Reaching consensus on value of solar
methodology and converting that into a compensation rate can be challenging. A small change in a
compensation rate can result in large changes in the economics of DER systems. Studies on the values of solar
have varied in their methodologies and results. For example, a comparison of studies completed by Montana
and Maryland shows Montana valuing solar 88 percent less than Maryland, with much of the difference
resulting from vastly different retail rates (Utility Dive 2018). The causes of disparities relate to choices about
which costs and benefits should be monetized (ICF 2018). For example, a study in Maine found the value of
solar to be five time more than the retail rate (ME PUC 2015).

Many states are considering to update or have updated net metering policies. In response to stakeholder
concerns, value of solar studies, program reviews and other research, some states are adopting alternative
incentive structures that credit customers at a lower rate than the full retail rate for energy passed back to the
grid. Other state policy changes include basing export credit rates based on time of day, creating separate
customer classes for DERs, changing periods when credits must be netted out, raising caps on existing
programs, and adding provisions for virtual net metering to enable access from community solar projects.8 To
ensure customers with DER systems are still paying for the services they receive from accessing the grid, some
states have implemented or increased fixed minimum bill charges or grid access charges. In nearly all states
and the District of Columbia, state utility regulators and legislatures have formally explored alternatives to
their respective system of net metering (NRRI 2019).

Making changes to net metering programs can be contentious. Some utility industry stakeholders argue that
policy and program reforms are needed because with higher program participation rates, the cost of energy
rises for utilities that purchase the excess energy at retail rates. Solar industry and environmental stakeholders
often advocate to maintain compensation at retail rates or institute a slower, more gradual decline in the rates
to prevent rapid disruptions to the industry. For example, when Hawaii implemented a policy change that
ended net metering in 2015, permit applications for distributed solar PV systems on the island of Oahu
decreased between 30 to 50 percent in the following three years (GTM 2019; 2017a).

Some states have introduced tariff structures to compensate customers with DER systems for the value of the
energy based on time and location, rather than at the constant retail rate. For example, after Hawaii ended its
net metering program, the Public Utilities Commission approved a Smart Export program for customers with
both solar and storage systems. During the daytime hours of 9 a.m. to 4 p.m., when the islands' grids typically

7	This research specifies net metering of distributed solar PV systems (LBNL 2017). A majority of net metered capacity is solar PV
(LBNL 2017).

8	Shared renewable projects, community solar, or community shared solar (CSS) programs are large PV systems that provide power
and/or financial benefit to multiple community members. These programs expand access to solar power to renters, those with
shared roofs, and those who are unable to install solar systems for financial or other reasons. These programs are particularly
beneficial to low- and moderate-income customers, who may face barriers to installing rooftop PV such as high upfront costs, low
homeownership rates, and limited access to credit (NREL and CESA 2018; CESA 2019).

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reach the maximum amount of solar energy they can accommodate, the program provides no compensation
for distributed solar generation. The program compensates participants for power sent to the grid during the
evening peak period or overnight when solar resources do not generate much energy and the utility would
otherwise rely on fossil fuel generators. Rates vary by island where the DER operates (Hawaiian Electric n.d.).

Other examples of states that have replaced or updated their net metering policy with an alternate rate design
include Utah and Nevada. In 2017, the Utah Public Service Commission (PSC) approved a stipulation between
Rocky Mountain Power and others to replace net metering with an export credit, which paid a lower standard
rate than the retail rate for each unit of energy exported to the grid for new systems brought online. In 2020,
the Utah PSC determined the value of the export credit rate that is based on avoided cost principles and closer
to wholesale electricity prices (UT PSC 2020). In Nevada, after the Public Utilities Commission eliminated net
metering in 2015, the legislature passed Assembly Bill 405 in 2017 establishing a new net metering program
with compensation levels that gradually step down as solar penetration increases (GTM 2017b). For more
details on Utah and other states, refer to the State Examples section of this chapter.

Various stakeholders have sought changes to net metering policies not only at the state level, but also at the
federal level. In 2020, FERC considered a stakeholder petition, filed by the New England Ratepayers
Association, that sought to end state regulation of net metering rules by transferring jurisdiction to federal
authority (FERC 2020b). There was broad opposition from state and DER stakeholders and FERC ultimately
rejected the petition. The case provides another example of the uncertainty of the future policy landscape.

Updating and Streamlining Interconnection Processes for DERs

Some stakeholders are seeking changes to state interconnection standards. In some states, the changes would
address interconnecting certain sizes or types of DER systems. The typical capacity size (in megawatts, MW) of
a residential or small business-scale rooftop PV project is much smaller than that of a commercial, industrial, or
utility scale PV system, and the interconnection standards can vary accordingly. The text box, The Current
Landscape of Interconnection Based on DER System Size, summarizes general interconnection standards by
project size. States may revise interconnection standards to address DER system safety or reliability, or to
clarify processes around newer DER technologies.

The Current Landscape of Interconnection Based on DER System Size

•	10 MW or larger systems. FERC has jurisdiction over developing standard interconnection requirements for larger
systems that are connected directly to the transmission grid. Historically, electric utilities owned most grid-connected
generation systems. As a result of restructuring and other legislation (e.g., the Public Utility Regulatory Policy Act or
PURPA), utilities were required to interconnect non-utility owned generators to the electric grid. States and
regulatory agencies such as FERC have begun to develop or have already implemented interconnection standards
for non-utility generators.

•	0.1 MW (100 kW) to 10 MW systems. This intermediate group represents systems that are interconnected to the
distribution system but are larger than the systems typically covered by net metering rules. These systems are
smaller than the large generating assets that interconnect directly to the transmission system and that are regulated
by FERC. In response to the mounting demands by customers and DER developers to interconnect generation
systems to the grid, utilities have increasingly established some form of interconnection process and requirements.
In addition, to increase utility confidence around DER systems, industry organizations such as the IEEE and UL
have begun to develop standards that enable safe and reliable interconnection of generators to the grid. However,
states need to ensure that interconnection standards are established for generation systems of all sizes.

•	Less than 100 kW (0.1 MW) systems. Some states have developed rules for the net metering of relatively small
systems (i.e., less than 100 kW). These procedures are not typically as comprehensive as interconnection
standards, but they can provide a solid starting point for industry, customers, and utilities with respect to the
connection of relatively small DER systems to the electric grid.

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Some state regulators are revising interconnection standards for energy storage, which is a growing market for
residential customers. In the future, customers may increasingly consider installing energy storage systems,
either with or without onsite generation, and states may need to update their standards to ensure these new
systems are addressed. In California, the CPUC revised regulations on energy storage interconnection and rules
surrounding energy storage systems exporting electricity to the grid, and clarified requirements for how
bidirectional electric vehicle charging can be interconnected with utility permission (CPUC 2020). These
revisions aim to clarify energy storage technology interconnection requirements (for more information on
interconnection standards in California, refer to the State Examples section of this chapter).

Hosting Capacity Analysis

Hosting capacity analysis (HCA) is modern grid planning activity that can be used to expedite the
interconnection process. HCA is used to help utilities and developers understand the threshold at which
additional DERs will trigger an upgrade to the electrical system. It can be used as an analytical pre-screening
process to determine whether a distribution system can accommodate new DERs (e.g., distributed PV, storage,
and electric vehicles) at specific locations without upgrades. HCA increases transparency into current
operational conditions and limits through maps and supporting datasets. The information can help state
regulators and utilities identify where in the distribution system new DERs could provide beneficial services
and support longer term strategic DER investment decisions, weighing the benefits against the costs to
upgrade the local distribution system. The insight from HCA maps and data on current grid conditions and
operational constraints allows a utility customer or DER developer to target specific grid locations for a cost-
and time-efficient DER interconnection process (IREC 2018). HCA establishes the baseline of the maximum
distributed generation the grid could accommodate safely, considering thermal, voltage, and protection limits
(ICF 2016). After the initial process of identifying operating limits, HCA may consider the locational value of
additional DERs on the grid (ICF 2016).

In some states, including California, Hawaii, Minnesota, and Nevada, utility regulators require utilities to
produce HCAs to support distribution system planning and grid modernization (IREC 2018). Some utilities, like
National Grid in Rhode Island, create interactive maps that incorporate HCAs and other information, such as
sea level rise estimates and the utility's non-wires alterative program (National Grid n.d.). The Interstate
Renewable Energy Council recommended to the Colorado Public Utilities Commission the following HCA
process (IREC 2020):

1.	Rulemaking sets general HCA requirements.

2.	Utility regulator hosts workshops to identify criteria to guide HCA implementation and selects criteria via

3.	Utility performs HCA, validates data, and publishes results.

4.	Utility regulator tracks results, learns about latest improvements, and evolves requirements.

Different tools are available to conduct HCA, such as the Electric Power Research Institute's DRIVE software
(EPRI n.d.). Figure 1 presents an example of a distribution system HCA map produced by Southern California
Edison (IREC 2019). As methods and tools are refined, HCAs can produce increasingly accurate maps and
datasets and become more useful for streamlining interconnections, reducing time and expense, and better
supporting grid planning and optimization.

A policy that is closely linked to the interconnection process is cost allocation for distribution system upgrades.
Generally, states operate on a first-come, first-served basis, which means that if you are the first to connect to
a distribution system feeder line, you are free to do so. Once that line reaches its capacity, the next customer
who wants to connect their DERs to the line must pay for the upgrade. These upgrades can make projects

order.

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prohibitively expensive, preventing further integration of DERs in that area until the line is upgraded. HCA
helps customers and developers understand where there is capacity to connect without incurring the large
costs of upgrading the line (NREL 2018b). Some states, like New York, have changed these policies to allocate
the costs of upgrades across the entire customer base who benefit from the additional DERs and availability of
new line capacity. In January 2019, the New York PSC approved the Cost-Sharing 2.0 Proposal, which covers
DERs of 5 MW or less and reduces the upfront costs to upgrade lines (HodgsonRuss 2021).

Figure 1. Hosting Capacity Analysis Map produced by Southern California Edison

H Southern California Edison OR PEP

Designing Effective Interconnection Standards and Net
Metering Rules

States consider several key factors when designing interconnection standards and net metering rules to
balance the needs of DER customers and owners, utilities, clean energy developers, and the public. To
design effective polices, states can promote broad stakeholder participation during policy development,
address a range of technology types and sizes for interconnection and net metering, and consider
current barriers to customer participation. To maximize the benefits of DERs to the grid, to customers,
and for the environment, states may also consider adopting modern grid planning and analysis
approaches to strategically plan for and facilitate DER interconnections.

Participants

Key stakeholders who can contribute to the process of developing effective interconnection standards and net
metering rules include the following:

• Electric utilities. Utilities are responsible for maintaining the reliability and integrity of the grid and

ensuring the safety of the public and their employees. Investor-owned utilities (lOUs) are privately owned

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utilities that are directly overseen by the state utility regulators. Other utility stakeholders that may not be
under the jurisdiction of the state utility regulators include:

Publicly Owned Utilities (POU). POUs are normally non-profit utility companies organized by the
community and run as a division of local government. This type of utility is governed by a local city
council or an elected or appointed board and sells power directly to the community it represents.

Electric Cooperatives (Co-ops). Electric cooperatives are private, independent electric utilities, owned
by the customers in the service area. They operate on a non-profit, cost-of-service basis.

•	State Utility Regulators. Regulators have jurisdiction over lOUs and, in some cases, cooperatively and
municipally owned utilities. They are often instrumental in setting policy to integrate or encourage onsite
generation, and are legally required to ensure the safety, accessibility, affordability, and reliability of
the electricity grid.

•	Developers arid owners/operators of DER systems and their respective trade organizations. Developers and
the customers that will rely on these systems can provide valuable technical information and real-world

•	Technical allied organizations. Organizations such as the institute of Electric and Electronic Engineers (IEEE)
and certifying organizations like the Underwriters Laboratories (UL) have been active in establishing
interconnection protocols and equipment certification standards nationwide. In addition, organizations
such as the Interstate Renewable Energy Council (IREC) help to develop national standards related to
interconnection and net metering policy and to advance regulatory policy innovation.

•	Regional transmission organizations (RTOs). These organizations may have already implemented
interconnection standards using FERC's requirements for large non-utility generators, generally above 10
MW.

•	Other government agencies. Federal (e.g., FERC) and state environmental and public policy agencies,
including state consumer advocates, can play an important role in establishing and improving
interconnection standards and net metering rules.

•	Public or utility customers. Customers that purchase electricity from utility companies.

•	Utility Consumer Advocates. These government or non-government organizations who represent
ratepayers seek to promote and advocate for the interests of utility customers. Some states have a
citizens' utility board (CUB) that actively participates in utility regulatory proceedings, advocates for
ratepayers in rate cases, and promotes clean energy and consumer protections. The Illinois CUB, for
example, joined rooftop solar supporters to advocate on behalf of net metering customers in a 2020 case
before the Illinois Commerce Commission that would have otherwise allowed the utility (Ameren) to end
net metering credits sooner based on how Ameren implemented the five percent net metering cap (IL CUB
2020).

•	Customers and community-based organizations. Communities of color, low-income households, and
residents of particular home types (for example, residents of manufactured homes or multifamily
buildings) are participants whose insights are important for equitable policymaking, yet many of these
customers experience barriers to participation (DOE 2016). States vary on how easy or difficult it is to
engage on a utility regulator proceeding. Some states hold public workshops and create public comment
processes to help build the capacity of community members and advocates to participate in regulatory
proceedings and policymaking (Synapse, RAP, and Community Action 2020). Six states have active
intervener compensation programs out of 16 that have authorized reimbursement for involvement in

scenarios.

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proceedings (NARUC 2021). In some states, community-led organizations that represent historically
underrepresented communities are active participants in policymaking. For example, in 2021 the California
Low-Income Consumer Coalition advocated for the interests of low-income ratepayers by joining the CPUC
proceeding on a successor to the net energy metering tariff and submitting comments regarding enhanced
consumer protection measures for customer-generators, tariff transparency and customer understanding,
and equity among customers (CLICC 2021). The text box has more information on inclusive practices to
encourage underrepresented stakeholders in the development of net metering rules and interconnection
standards.

• Environmental Organizations. These non-government, non-profit organizations advocate for the

conservation, protection, and/or optimal management of environmental resources against their misuse or
degradation caused by human misuse. The organizations may advocate for the fair treatment and
meaningful involvement of all people with respect to the development, implementation, and enforcement
of environmental laws and energy regulations.

Practices for inclusive Engagement when Developing Net Metering Rules and Interconnection

•	Offer evening and weekend options for stakeholders to participate in hearings, workshops, public meetings. Provide
intervenor training, translation services, and other informational community outreach activities to better include
groups historically underrepresented in the standards-setting process, such as communities of color and low-income
communities (Synapse, RAP, and Community Action 2020).

•	Address historic and systematic barriers to participation by underrepresented groups and communities with
environmental justice concerns and engage with community-based organizations and Tribes (DOE 2016).

•	Require environmental and social justice evaluations during the policymaking process (Washington and California
incorporate this practice into their state process).

•	Financially compensate residential or small commercial customers who experience financial hardship as a result of
participation as interveners in a commission proceeding (e.g., presenting evidence or arguments that factor into the
final decision), even if the commission does not ultimately align with the intervener's position. California offers an
example of this approach to intervenor compensation (NARUC 2021).

Typical Specifications for Interconnection and Net Metering

The specifications described in this section reflect typical elements found in existing state policies. The text

boxes describe best practices derived from current literature or from existing state policy examples.

Specifications for Interconnection

States can promote clean DERs with comprehensive interconnection standards that address the following

elements:

•	System size requirements. State policies may establish individual system capacity limits and ensure that the
policy applies to all state jurisdictional interconnections.

•	Technology and technical standards. State requirements may specify or prioritize certain technologies that
may be interconnected (e.g., inverter-based systems, induction generators, synchronous generators). In
addition, states can keep metering requirements to a minimum and allow customers to opt-out of an
external disconnect switch for smaller, inverter-based systems. A disconnect switch would add to start-up
costs but would provide electricity resiliency benefits, for example during a power outage. It would enable
a DER host customer to safely consume directly the electricity generated by its onsite renewable DER
system after disconnecting from the grid.

Standards

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•	Components. States often list required components of the electric grid where the system will be
interconnected (i.e., radial or network distribution, distribution or transmission level, maximum aggregate
DER capacity on a circuit).

•	Application fees and timelines. States can establish reasonable limits on interconnection application fees
and timelines for system interconnections. Effective policies keep application costs to a minimum,
especially for smaller systems, which promotes equitable access to DERs for residential and small business
customers and ensure that timelines are imposed and enforced.

•	Limitations on liability insurance requirements. States may prevent utility requirements for customers to
purchase liability insurance (in addition to the coverage provided by a typical insurance policy) or add the
utility as an additional insured.

•	Battery storage. States may consider net metering policies that include regulations on behind-the-meter
battery interconnection and rules surrounding exporting stored electricity to the grid.

•	Review process. Best-practice policies generally allow for different tiers with different levels of review to
accommodate systems based on system capacity, complexity, and level of certification.

•	Project technical screens. Clean and transparent technical criteria for screening projects facilitates
evaluation and supports effective policy implementation.

•	Customer redress. These provisions specify the option to hold utilities and owners accountable for
following the standards.

Some states are developing application processes and technical requirements for differently sized or certified
systems. Since a DER system's size can range from a renewable system of only a few kilowatts (kW) to a CHP
system of tens of MW, standards can be designed accordingly. Several states have developed a multi-tiered
process for systems that range in size from less than 10 kW to more than 2 MW. Similar to the FERC guidelines,
some states (Colorado, Florida, and North Carolina) have divided DER systems into three categories based on
generator size. Other states use fewer categories (such as New York, Georgia, and West Virginia) or more
categories (such as Delaware, Illinois, and Maine, which each have four). States define fees, insurance
requirements, and processing times based on the DER category. The level of technical review and
interconnection requirements usually increases with generation capacity, although the requirements are
ultimately prompted by the applicant's impact on the grid as determined through the study process and the
criteria identified in the application process. Simplified interconnection processes for the smallest projects
helps offset the absence of financial or technical resources available to customers likely to pursue a smaller
system. The simplified processes can enable a wider range of residential or small business customers to install
DER projects (NCCETC 2021).

In states with a multi-tiered interconnection process or preliminary technical screen, smaller systems that
meet IEEE and UL standards or certification generally pass through the interconnection process faster, pay less
in fees, and require less protection equipment because there are fewer technical concerns. States that require
faster application processing for smaller systems (up to 30 kW) include California, Connecticut, Massachusetts,
Michigan, Minnesota, New York, and Utah. For relatively large DER systems, processes and requirements may
be similar or identical to those used for large central power generators. For mid-size systems, states may need
to develop several levels of procedural and technical protocols to meet the range of needs for onsite
generators, utilities, and regulators.

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Best Practices for Interconnection Standard Policy Design

States seeking to support clean DER through interconnection standards may consider taking the following actions:

•	Work collaboratively with interested parties to develop interconnection standards that are clear, concise, and
applicable to potential DER technologies. Proactively seek participation of social or environmental justice groups and
community groups, offering intervener training and meetings outside typical workday hours. Collaborate with
technical experts and customer advocates to streamline the process and avoid untimely and costly rework.

•	Develop standards that cover the scope of the desired DER technologies, generator types, sizes, and distribution
system types.

•	Avoid restrictive requirements that place unnecessary mandates on customers to buy iiability insurance or require
customers to make the utility an additional insured party.

•	Consider adopting portions of national models (such as those developed by the National Association of Regulatory
Utility Commissioners, IREC, and FERC) and successful programs in other states, or consider using these models
as a template in developing a state-based standard. Consider that consistency within a region increases the
effectiveness of these standards.

•	Apply common state practices that reduce industry compliance costs. The NREL SolarAPP+ is a free online tool
designed to create a standardized process.

•	Maximize consistency between the RTO and the state standards for large generators.

•	Broaden DER access to residential or small business customers by making the interconnection process less
complex, less time-intensive, and more affordable for projects below a determined size threshold.

•	For small DER systems, omit unnecessary hardware requirements, offer expedited applications and approvals,
combine applications for multiple aspects of a project, offer pre-filled online forms that are easy to modify and
submit, provide grid infrastructure information accessible online, publish clear and predictable timelines for each step
in the process, and maintain a transparent online queue of applicants.

IREC provides more information in its Model Interconnection Procedures. (2019).

Specifications for Net Metering

States can promote clean DERs with comprehensive net metering rules that address the following elements:

•	REC Ownership. States may allow the DER host or owner of a net metered system to retain ownership of
Renewable Energy Certificates (RECs) produced by the system, unless transferred to the utility or another
party in exchange for acceptable compensation. A REC is a market-based instrument that represents the
rights to the environmental, social, and other non-power attributes of renewable generation. Only the
owner of the REC can "retire" the REC, which means the REC can no longer be traded and the owner can
then claim the use of renewable energy.

•	Rollover policy. States may provide flexible options for retail rates and credits to enable customers to roll
unused credits into a defined number of billing cycles. States can specify that customers are to be paid for
annual net excess generation or at a different set time interval, such as monthly or the number of billing
cycles.

•	Rates. States may specify the exact rate or delegate the rate to be determined in proceedings before utility
regulators. Customers are usually compensated at or near the retail rate with net metering programs, but
some states are updating their programs with generally lower compensation rates. Rates are rarely below
the average daytime wholesale price at which the utility would otherwise have to purchase the electricity.
Arizona uses an innovative approach involving a resource comparison proxy to determine the amount of
compensation per kWh a customer receives for solar generation. The resource comparison proxy is
updated annually and based on avoided cost principles, tying the rate to the utility-scale price of similar
solar resources (APS 2017), The rate takes avoided transmission and distribution losses into account, and it
limits how much the rate can drop in a single year. This approach, which replaced the state's original net
metering program, was approved by Arizona Corporation Commission in 2017 (AZCC 2017). After this

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approach was implemented, there was a drop in residential solar PV installations, but in 2021 there were
more residential installations than in 2017 (SEIA 2021).

•	New metering equipment. States can avoid requiring retail electric customers to purchase new metering
equipment. States can require utilities to make smart metering and other digital technology for energy
management available to solar and other customers on a non-discriminatory and open-access basis.
Integrating smart meters or other advanced metering technologies can lead to more detailed and reliable
meter data, which in turn can lead to more efficient planning and energy use.

•	Shared renewables, community renewables, and virtual net metering. States may provide an option for
shared renewables (e.g., community solar), which is a billing approach often appealing to utility customers
whose onsite solar resource potential is limited, those who rent, and those who cannot afford the upfront
cost or are otherwise unable or unwilling to install a clean DER system on their residence or commercial
building. States have taken one of three legislative paths to authorize shared renewables: virtual net
metering, community renewables programs, or a hybrid of these (NCSL and NASEO 2017). As of 2020, 39
states and Washington, DC, have community solar projects, and 20 states and Washington, DC, have
policies that support community solar (NREL 2021b). Net metering or alternative arrangements, such as
group billing or joint ownership, can credit shared renewables participants; however, eligibility depends on
utility and state-level requirements. Colorado, for example, has legislation on community solar that allows
systems to qualify if they are (1) in the same county as its subscribers, and (2) between 10 kW and 2 MW.
In Colorado's framework, participants receive a credit on their bill after transmission costs are subtracted
(Low-Income Solar 2018). In Florida, the PSC recently approved Duke Energy Florida's Clean Energy
Connect Program, which enables all customers, whether or not they have physical access to a PV system,
to subscribe to kilowatt blocks of solar from a portfolio that provides a monthly bill credit based on their
subscription (FL PSC 2021).

•	Meter aggregation. States may allow for a utility customer's DER project to offset their electricity use from
multiple meters on their own or another adjacent property. Examples include a solar PV system on a farm
where multiple loads are metered, or a government owned DER system that offsets the electrical use of
adjacent, separately metered government buildings.

•	Fixed costs and externalities. States may enact policies that require customers to pay for the fixed costs
and externalities that result from net metering systems to mitigate cost-shifting to other ratepayers. This
can be done through minimum bill requirements or grid access charges. Such policies may include time
varying rate structures for net metering customers, or program monitoring or review requirements to
determine the net metering program's impact on low-income customers.

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Best Practices for Net Metering Standard Policy Design

States seeking to support clean energy through net metering may consider the following actions:

•	Ensure that the value of DER electricity is quantified fairly and that DER customers are adequately compensated.

•	Ensure the customer's right to generate electricity and connect to the grid without discrimination or undue process.

•	Evaluate the costs and benefits of net metering on participants and non-participants. If the utility implements charges
to recover embedded net fixed costs, ensure that these charges are applied only after accounting for all utility
benefits and offsetting all cost reductions from DER.

•	Consider time varying rates for net metering customers.

•	Establish measures to monitor the program's impact on the energy burden of low-income customers.

•	Ensure that net metering rules, regulations, and practices are applied consistently statewide.

•	Ensure that the policy provides transparent access to data, such as load data (including hourly profiles), so
customers can understand the economic implications of adopting onsite clean energy technologies.

•	Avoid restrictive total program or state (aggregate) capacity limits or individual system capacity limits beyond that of
the host customer's load or electricity consumption.

•	Ensure transparency in who retains renewable energy certificate (REC) ownership and their associated
environmental and social attributes.

•	Make DERs affordable for and accessible to more customers. Allow collective ownership and/or net metering
policies that enable a group of customers to share the costs and benefits of a DER system (e.g., community solar).

•	Incentivize utilities to include small businesses, low-income communities, and communities with environmental
justice concerns in clean distributed energy projects by implementing targets for DER for these communities.

•	If creating or increasing incentives, ensure the interconnection process can handle the increased application load
before the incentives are enacted.

IREC provides information on best practices for net metering policy design in its publications Model Net Metering
Rules (2009) and Model Interconnection Procedures (2019).

Interaction with Federal Policies

States have found that several federal initiatives, particularly FERC standards, can be used when designing
their own interconnection standards. Relevant and recent FERC orders are summarized as follows:

• FERC, in 2006, set standard terms and conditions for interconnections under FERC jurisdiction at the
transmission level for public utilities to interconnect new DER sources by issuing Small Generator
Interconnection Procedures (SGIP) and Small Generator Interconnection Agreement (SGIA). The SGIP
contain technical procedures as well as standard contractual provisions, They provide three ways to
evaluate an interconnection request. The SGIP require interconnection equipment to be certified
according to IEEE Standards 1547 and IJL 1741. The SGIA was updated with specific technical requirements
intended to improve grid resilience and reliability in 2016 and again in 2018 with FERC Order No. 842 (FERC
842 2018).

Under the Public Utility Regulatory Policy Act (PURPA), utilities are required to allow interconnection by
qualifying facilities. States have significant flexibility in administering PURPA, although amendments made in
2005 and FERC decisions have limited the applicability of PURPA in some regions, particularly for facilities
larger than 20 MW. In 2010, FERC ruled that California's "multi-tiered" avoided-cost-rate structure for a feed-
in tariff for CHP systems of up to 20 MW is consistent with PURPA. FERC affirmed that state procurement
obligations can be considered when calculating avoided cost, for example, when states require utilities buy
particular sources of energy with certain characteristics (e.g., renewable energy) to meet procurement
obligations (FERC 132 2010). In 2020, FERC amended PURPA through Orders 872 and 872-A in response to the
many changes in the energy landscape in recent decades. Some of the changes gave state regulators more
flexibility, for example, by allowing states to incorporate market forces in establishing avoided cost rates for
qualifying facilities (FERC 2020f; 2020d). The changes may prompt states to revisit their interconnection

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standards and net metering rules as regulators and utilities implement the PURPA amendments (APPA, EEI,
NARUC, and NRECA 2021).

•	Energy storage became an eligible resource type to interconnect under FERC SGIP procedures in 2013 through
FERC Order 792. States may want to consider how state interconnection standards accommodate storage
assets and how they interact with existing FERC orders (FERC 2020c). While FERC's updates are not binding for
states, they can provide useful models for establishing provisions that anticipate and enable higher DER
penetration.

•	In 2020, FERC dismissed a New England Ratepayers Association petition, which was filed to request (1) that
FERC declare exclusive federal jurisdiction over wholesale energy sales from generation sources located on
the customer side of the retail meter, and (2) that rates for such sales be priced in accordance with the
Federal Power Act (FPA) or PURPA (FERC 2020a; DOE n.d.). Those in favor of the petition argued that by
compensating customers or companies who operate these systems for their excess electricity at retail
rates, ratepayers end up paying more for electricity that could be purchased at the lower wholesale rates,
resulting in a regressive cost-shifting from rooftop solar owners, who generally have higher incomes, to
low-income ratepayers. Those against the petition argued that net metering is an integral element of retail
billing, which is strictly a state jurisdictional issue and that net metering transactions are local by their
nature because net metering concerns the relationship between the retail customer and the local utility.
The petition was rejected on procedural grounds, and Commissioners' notes in their concurrences
indicated that the jurisdictional merits of the case were stiil unanswered by FERC (FERC 2020a).

Interaction with State Policies

Interconnection standards and net metering rules complement other clean energy policies and programs such
as state renewable portfolio standards, clean energy standards, utility incentive mechanisms, and utility
planning practices, which are covered in other chapters of the Guide. For example, the utility incentive
mechanism of performance-based regulation (PBR), which can be implemented by utility regulators, could tie a
small part of utility revenue to interconnections. Specifically, regulators can use performance incentive metrics
(PIMs) for interconnection request timelines or incentivize PV adoption by applying PIMs to the number of new
residential PV customers added in a service territory. PBR equity and affordability metrics could also
accompany interconnection standards and net metering rules to better align overall utility financial interests
with goals to reduce customer bills for low-income customers. Interconnection and net metering policies can
also help states achieve other related environmental, energy, and economic goals. For example, by providing
incentives to site renewable energy on brownfields (formerly contaminated lands), landfills, or mine sites, the
state can help protect open space and transform blighted properties into community assets.

Implementation and Evaluation

This section describes the implementation and evaluation of interconnection standards and net metering
rules.

Implementation

State legislatures and utility regulators may develop interconnection standards and net metering rules, and
utilities are ultimately responsible for their implementation. Facilitating the interconnection process is a
primary implementation activity. By establishing clearly defined categories of technologies and generation
systems, utilities can streamline the interconnection process for customers and lessen the administrative time
related to reviewing applications. In some states, utilities create multiple categories and tiers for reviewing

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applications with established maximum review periods, in accordance with state policy. Across these
technology categories, the maximum processing time allowed can vary by more than a factor of five depending
on the technical complexity and size of the interconnection. Several states (including California, Connecticut,
Massachusetts, Michigan, Minnesota, New York, and Wisconsin) have created tiered application processes
based on system size and other factors. This tiered approach streamlines the process for smaller systems while
maintaining a standard process for larger systems.

•	A streamlined process that applies to smaller or simpler (e.g., inverter-based) systems could have lower
fees, shorter timelines, and fewer requirements for system impact studies. In some cases, states (i.e.,
California and New York) have pre-certified certain devices. Other states (i.e., Connecticut, Massachusetts,
Minnesota, New Jersey, and Texas) require compliance with UL 1741 or IEEE 1547 and other applicable
standards to expedite approval. In addition to streamlining processes, Minnesota's 2018 update of
statewide interconnection standards allows customers to request relevant grid information before they
start their interconnection application and requires utilities to maintain a publicly available transparent
application queue that tracks timeline compliance (MN PUC 2018).

•	Systems in a standard process are subject to a comprehensive evaluation. Applicants for these systems are
typically required to pay additional fees for impact studies to determine how the DERs may affect the
performance and reliability of the electrical grid. Because of the higher degree of technical complexity,
fees are higher and processing times are longer.

There is tremendous diversity among the key elements of interconnection standards recently established at
the state level. The detailed state examples at the end of this chapter illustrate different approaches to
application process elements like fees, timelines, and eligibility criteria. Greater similarities are emerging
among states' technical requirements, and this consistency makes it easier to increase the amount of clean
DERs in the states.

Evaluation

Utilities and state regulators may conduct evaluation of interconnection application process timelines to
ensure an efficient process for customers. As noted previously, some states monitor the timing of
interconnection applications from receipt to final interconnection agreement. This enables the states to
determine how standards affect the process for applicants by types and sizes of interconnected systems.

States can monitor utility compliance with the new standards and timelines. States can also consider
approaches to accountability.

As previously noted, many states are evaluating reimbursement rates and considering or adopting changes to
their original net metering policies. For example, some states are evaluating their policy approach to improve
equitable distribution of cost burdens among DER stakeholders.

Action Steps for States

Some states have adopted successful interconnection standards and net metering rules that expedite the
implementation of clean energy technologies while accounting for the reliability and safety needs of utility
companies. This section provides examples of action steps for states establishing interconnection and net
metering policies and procedures, and for ensuring ongoing success after the policies are adopted.

Importantly, the success of effective interconnection standards is enhanced by effective net metering rules.
States that have recognized the need for concurrent net metering policy have either incorporated net
metering rules into the interconnection standards or established separate net metering rules.

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States with Existing Interconnection and Net Metering Policies

A priority after establishing interconnection standards and net metering rules is to evaluate the policy
implementation and mitigate issues that might adversely affect success. In addition, being able to demonstrate
and communicate the benefits of the policies is critical to their acceptance and use by stakeholders. States that
have existing interconnection and net metering policies may consider taking the following steps to optimize
policy effectiveness:

•	Compare existing state interconnection and net metering policies to established model rules and best
practices.

•	Monitor interconnection applications from the time of receipt to the time of final interconnection
agreement. Determine how the standards affect the application process and how they impact different
types of interconnected systems. Consider monitoring utility compliance with the new standards and
timelines, and creating a point-of-contact to resolve disputes or noncompliance.

•	Consider updating interconnection standards or net metering rules as needed in response to the results of
monitoring and evaluation activities. For smaller DER systems, if there are disproportionally high costs or
long durations to interconnect to the grid, consider streamlining the policy for small DER systems to limit
the length of the application review periods or technical requirements.

•	Identify an appropriate organization to maintain a database on interconnection applications and new
DER systems, evaluate the data, and convene key interconnection stakeholders when necessary.

•	Consider whether interconnection standards and net metering rules can indirectly support utility initiatives
designed (1) to advance equity by increasing access and reducing barriers to DER adoption for targeted
communities, and (2) to increase electricity affordability for low-income customers. This can be done by
providing access to community-based DER systems such as shared solar projects.

States without Existing Interconnection and Net Metering Policies

Stakeholder support can help facilitate and accelerate the development of new policies. Gaining stakeholder
support is a first step for a state that seeks to establish interconnection and net metering policies. The
following strategies foster support from public officials and other stakeholders:

•	Determine the level of demand and support for interconnection and net metering policies from public
office holders and key industry members (e.g., utilities, equipment manufacturers, project developers,
potential system owners).

•	Conduct an analysis of proposed policy costs and benefits to stakeholders in the state, perhaps
accompanied with a pilot program.

•	Implement an educational effort targeted at key stakeholders to raise awareness of potential benefits of
net metering policies.

•	Establish a collaborative working group of key stakeholders to develop recommendations for a standard
interconnection process and technical requirements if the state has DER regulations. One approach is for
the state utility regulator to open a docket with the goal of receiving stakeholder comments and
developing a draft regulation. Another option is to work with members of the legislature and the utility
regulator to develop support for the new interconnection and net metering policies.

•	Consider implications of DER incentives (e.g., new net metering program) on the volume of
interconnection applications. Expect that implementing interconnection standards may take some years.

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•	Consider developing the state interconnection standards before increasing incentives to DER adoption, for
example to avoid a backlog of interconnection applications.

•	Consider existing federal and state standards while developing new interconnection procedures. Rely on
accepted IEEE and UL standards to develop interconnection technical requirements.

State Examples

Massachusetts

Massachusetts is a national leader in net metering policy and in
the amount of total net metered energy sold back to the utility,
which in 2020 was 717 GWh, approximately 28 percent of all
net metered energy sold back in the United States (EIA 2020).
The state's successful efforts to encourage clean DER
development can be attributed to the state's net metering
policy design. In 2009, the Massachusetts Department of Public
Utilities (DPU) issued its model net metering tariff. DPU
required ail lOUs in the state to offer net metering and to
ensure that the net metering tariffs are consistent across all
participating utilities (MA DPU 2009).

Massachusetts Policies Encouraged
High Levels of Net Metered Distributed
Generation

In April 2016, state legislation increased the net metering
aggregate capacity limits of a utility's peak load from four
percent to seven percent for private facilities and from five
percent to eight percent for government facilities (MA S.1979
2016). Massachusetts has a shared renewables billing policy,
called neighborhood net metering, that allows customers to
share the utility bill credits from renewable DER installations
among multiple customers that share in the ownership interest
in the facility (NREL 2016). Massachusetts adopted a new clean
energy and climate policy in 2021 that requires the state to
reach net-zero greenhouse gas emissions by 2050. It addresses
several aspects of net metering, and provides new exemptions
for net-metering caps for qualifying facilities (MA S.9 2021).

Massachusetts' interconnection standards apply to all forms of
DERs, including renewables, and to all customers of the state's
three lOUs: Unitil, Eversource, and National Grid. Both fossil-
fuel and renewable-fuel CHP systems are eligible for
standardized interconnection. However, only renewable-fuel
CHP systems are eligible for net metering (NREL 2016).

•	The state's net metering policy is open to
a variety of renewable and other DER
technologies.

•	Massachusetts allows neighborhood net
metering, a type of shared renewables
policy that expands participation to those
who may have been unable to afford the
total upfront cost of a DER project.

•	The state has a simplified, an expedited,
or a standard interconnection process
depending on the project size and
technical complexity.

•	State policies encourage renewable
energy on brownfields and landfills,
making Massachusetts a leader in
renewable energy redeveloping these
iands with over 125 sites with an
estimated 330 MW of completed in
Massachusetts.

Resources for more information:

•	Massachusetts Net Metering Guide

•	The Guide to Developing Solar

The state's complementary policies have encouraged clean energy expansion. For example, policies on
redevelopment of brownfields and closed landfills support DER development. As a result of its robust programs
and policies, Massachusetts leads the nation in siting solar projects on landfills and similar sites. The state
accounts for roughly 30 percent of all such installations across the country (EPA 2020). In 2018, the

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Massachusetts Department of Energy Resources established the Solar Massachusetts Renewable Target
(SMART) incentive program under authority granted by the state legislature. The program began with an initial
1,600 MW competitive procurement of solar projects developed by residential, commercial, governmental,
and industrial electricity customers throughout the state and expanded in 2020 with an additional 1,600 MW
procurement (MA DOER n.d.). The SMART program is a tariff-based incentive paid by the utility company
directly to the solar system owner connected to one of the three lOUs (MA DOER 2020).

Virginia

The Virginia Clean Economy Act, adopted in 2020, expanded
the state's net metering policy to further promote renewable
DERs and advance energy equity (VA H.B. 1526 2020). This
legislation increased the cap on facility-specific net metering
and the total amount of renewable energy that can be net
metered across a utility's service territory. The law also
designates a portion of the allowed net metering quantity for
low-income customers. The legislation specifies that the net
metering rate is to be established in a standard contract or
tariff and approved by the State Corporation Commission (SCC)

(VA H.B. 1526 2020). Specifically, the new law amends the net
energy metering program in the following ways:

•	increasing the maximum capacity of renewable generation
facilities of participating nonresidential eligible customer-
generators from one to three MW

•	increasing the cap on the capacity of generation from
facilities from the customer's expected annual energy
consumption to 150 percent of such amount

•	increasing each utility's systemwide cap from one percent
of its adjusted Virginia peak-load forecast for the previous
year to six percent of such amount, five percent of which is
available to all customers and one percent of which is
available only to low-income utility customers

The Virginia legislature adopted complementary legislation in
2020 directing the SCC to establish a shared community solar
program (VA H.B. 1634 2020). The shared solar programs bill required shared solar facility developers to
designate at least 30 percent of capacity to serve low-income customers, and utilities to monitor and report
the amount of capacity that has been allocated to low-income customers. The bill directed the SCC to establish
a monthly minimum bill that would be applied to shared solar subscribers, and to exempt low-income
customer participants from the minimum bill. To facilitate low-income customer and low-income service
organization participation in the program, H.B. 1634 directed the SCC to initiate a stakeholder process that
engages low-income community representatives and community solar providers (VA H.B. 1634 2020).

Virginia Clean Economy Act supports
Equity in Net Metering

Virginia's Net Metering Program is an example
of a state's legislature expanding net metering
in a way that considers low-income utility
customers. The expansion promotes equity by
specifically designating one-sixth of net-
metered projects to be available only to low-
income utility customers.

For more information, refer to the following:

•	Virginia Clean Economy Act

•	Virginia Code §56-594 on net metering
provisions

•	SCC net metering information

•	SCC shared solar programs and
applicable rules, including multi-family
shared solar program

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California

In 2020, California updated its long-established Electric Rule 21
that governs interconnection and operating requirements for
generation facilities connected to the electricity grid, which had
dated back to 1996. Rule 21 provides customers wanting to
install generating or storage facilities on their premises with
access to the electric grid while protecting the safety and
reliability of the distribution and transmission systems at the
local and system levels. Rule 21 governs Commission
jurisdictional interconnections, which include the
interconnection of all net energy metering facilities, non-export
facilities, and qualifying facilities intending to sell power at
avoided cost to the host utility. As a result of a 2012 settlement
agreement, CPUC directed utilities to implement a Fast Track
process in which all interconnection requests are screened by
size and complexity, allowing smaller less complicated projects
to continue through a streamlined review (CPUC n.d.).

The 2020 amendments to Electric Rule 21 updated the state
interconnection and net metering policies as part of an ongoing
rulemaking that began in 2017 (CPIJC 2021c). The changes add
grid flexibility to accommodate new technologies and allow for
more data-driven decisions. Overall, the updates are designed
to improve the efficiency, transparency, certainty, and clarity of
the interconnection process (CPUC 2021c). Specific changes
include the following:

•	Study requirements for interconnections are more streamlined and efficient

•	Battery storage interconnection is addressed, including standards for exporting stored electricity to the
grid

•	Bidirectional electric vehicle charging requirements are clarified (CPUC 2020).

California Improves Efficiency,
Transparency, Certainty, and Clarity of
the Interconnection Process

V

•	Electric Rule 21 allows streamlined
interconnection processes for small or
simple electricity generation or storage
projects.

•	Although in existence for a few decades,
Rule 21 is continuously undergoing
updates to accommodate new
technologies and policy goals.

For more information, refer to the California
Public Utilities Commission Electric Rule 21
webpage.

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Utah

Utah provides an example of a state that has replaced its net
metering policy with an alternate rate design, an Export Credit
Rate, which resulted in reduced compensation for exported
power from rooftop solar systems. Through the 2010s, Utah
Public Service Commission (PSC) required the state's IOU, Rocky
Mountain Power, and cooperatively owned utilities serving
more than 10,000 customers, to offer net metering to
customers who generate electricity. The state required electric
utilities to credit rooftop solar customers for excess power at
full retail rates. In March of each year, excess kWh credits were
applied to a utility low-income program at the avoided cost
value (UT 2015). Utah saw rapid growth in solar penetration as
a result of their net metering policy, falling costs for solar
installations, and state and federal incentives. Utah statute
authorized the Utah PSC to set a cap for the program, after
which, the PSC could transition to an alternative compensation
structure for new applications (UT PSC 2020).

In 2017, the Utah PSC approved a settlement stipulation
between Rocky Mountain Power (RMP) and numerous other
parties. The settlement ended net metering at retail rates,
created a transitional program, and required the establishment of an export code, which paid a lower standard
rate for each unit of energy exported to the grid. The PSC found the proposed approach to phasing out net
metering for DER customers and replacing it with export credits "offers a compromise that all stakeholder
groups generally believe to be acceptable, just, reasonable, and in the public interest" (UT PSC 2017).

Following this decision, the PSC implemented a transitional value for the export credit rate and began an
investigation into the costs and benefits of distributed solar. In 2020, the Utah PSC reviewed several proposals
to determine the value of the export credit rate. The final rate approved by the PSC for excess power is an
even lower, seasonal rate based on avoided cost principles that is closer to the wholesale electricity price (UT
PSC 2020).9

Rate Revision in Utah

*

Utah restructured rooftop solar customer
compensation by revising the rate paid to
rooftop solar customers to a lower rate that is
closer to wholesale prices. The lower rate
resulted in fewer rooftop solar PV
installations.

For more information, refer to the Application
of Rocky Mountain Power to Establish Export:
Credits for Customer Generated Electricity.

9 Utah's new export credit rate, which replaces net metering for customer generation, is 5.969 cents/kWh in summer rates and 5.639
cents/kWh in winter rates. These rates represent an avoided energy component of 2.439 cents/kWh in summer rates (June through
September); 2.109 cents/kWh in winter rates (October through May); plus total avoided generation, transmission, and distribution
capacity costs of 3.53 cents/kWh (UT PSC 2020). The framework that enables the PSC to determine how customers receive credits for
DER is established in the Utah Code § 54-15-101 et seq. Title 54 (Public Utilities), Chapter 15 (Net Metering of Electricity), established
in 2002 and last updated in 2016.

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Information Resources

Research Reports and Other Net Metering Resources

Title/Description

National Academies of Sciences, Engineering, and Medicine, The Role of Net Metering in the Evolving Electricity System
(forthcoming). This forthcoming study, which is mandated by Congress to be prepared for the Department of Energy, will
examine net metering and alternative mechanisms, impacts on the electricity grid and consumers, and potential
contributions of net metering to decarbonization, equity, and resiliency.

The National Conference of State Legislatures. State Net Metering Policies (2017). This report provides summary and
detailed information about state net metering policies and programs.

National Regulatory Research Institute. Review of State Net Energy Metering and Successor Rate Designs (2019). This
NRRI resource includes reviews of the regulatory status and changes to net metering, or DER program rate designs, from
2014 through mid-2018.

National Regulatory Research Institute. Review of State Net Energy Metering (2019). The appendix from this report,

Summaries of Recent State Actions on Net Energy Metering Policies in Five Vertically Integrated and Five Restructured
States, summarizes actions on net metering states across the United States such as rate design.

North Carolina's Clean Energy Technology Center. Database of State Incentives for Renewables and Efficiency (DSIRE).
This database provides information on the state's regulatory policies and financial incentives that support clean energy,
including net metering.

Regulatory Assistance Project. Designing Distributed Generation Tariffs Well: Fair Compensation in a Time of Transition.
(2016). This paper outlines current tariffs, including net metering, and considerations for regulators as they weigh the
benefits and costs of DERs for all stakeholders.

Federal Resources

Title/Description

Department of Energy. Solar Power in Your Community (2022). This guide provides case studies and approaches for local
governments and stakeholders to increase access to and development of solar PV.

Environmental Protection Agency and National Renewable Energy Laboratory. Best Practices for Siting Solar Photovoitaics
on Municipal Solid Waste Landfills (2013). This report addresses common technical challenges for siting solar PV on
municipal solid waste (MSW) landfills, including considerations around interconnection and net metering.

Environmental Protection Agency. dCHPP (CHP Policies and Incentives Database). This database allows users to search
for state-level or federal-level policies and incentives for combined heat and power, including interconnection standards
and net metering policies.

Environmental Protection Agency. RE-Powering America's Land: Mapping and Screening Tools. This website provides
tools for evaluating the renewable energy potential of current and formerly contaminated lands, landfills, and mine sites. It
includes information about incentives, case studies of successful projects, and a Decision Tree tool for determining site
suitability for solar or wind.

Environmental Protection Agency. The Combined Heat and Power Partnership (CHPP). This website provides information
about a voluntary program that seeks to reduce the environmental impact of energy generation by promoting the use of
CHP, The CHPP helps states identify opportunities for policy development to encourage efficiency through CHP and can
provide additional assistance to help states implement standard interconnection.

National Renewable Energy Laboratory. An Overview of Distributed Energy Resource (DER) Interconnection: Current
Practices and Emerging Solutions (2019). This report gives high-level and strategic-planning guidance on DER
interconnection topics such as standards, processes, and technologies.

National Renewable Energy Laboratory. The Effect of State Policy Suites on the Development of Solar Markets (2014).

This report examines the effectiveness of state policies in fostering successful solar PV markets and highlights the benefits
of net metering and interconnection policies for achieving market growth.

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National Standards Organizations

Title/Description

Institute of Electric and Electronic Engineers Standards Association. IEEE 1547 Standard for Interconnecting
Distributed Resources with Electric Power (2018). The IEEE Standards Association has developed standards
relevant to many of the technical aspects of interconnection. In particular, Standard 1547 provides requirements
relevant to the performance, operation, testing, safety considerations, and maintenance of interconnection.

Underwriters Laboratories Standards. UL 1741: Standard for Inverters, Converters, Controllers and Interconnection
System Equipment for Use With Distributed Energy Resources (2010). UL develops standards for interconnecting
DERs. UL 1741 combines product safety requirements with the utility interconnection requirements developed in the
IEEE 1547 standard to provide a testing standard to evaluate and certify DER products.

Examples of Interconnection Standards

Title/Description

Department of Energy, State and Local Energy Efficiency Action Network. The Guide to the Successful

Implementation of State Combined Heat and Power Policies (2013). This guide provides actionable information to
assist state utility regulators and policymakers in implementing key state policies that impact CHP. It discusses five
policy categories, including state approaches to interconnection standards for CHP.

Department of Energy. Connecting to the Grid: A Guide to Distributed Generation Interconnection Issues (2009).
This guide provides a model stakeholders can use to develop state-level interconnection standards.

Interstate Renewable Energy Council. Regulatory Engagement. IREC has prepared Model Interconnection
Procedures (2019) and various DER guidelines for policymakers.

References

AEE. 2018. "Distribution System Planning: Proactively Planning for More Distributed Assets at the Grid Edge."
Advanced Energy Economy.

https://info.aee.net/hubfs/Distribution%20System%20Planning%20FINAL%20-%2007-03-2018.pdf.
APPA, EE I, NARUC, and NRECA. 2021. "PURPA Title II Compliance Manual 2.0." American Public Power

Association, Edison Electric Institute, National Association of Regulatory Utility Commissioners, and
National Rural Electric Cooperative Association. https://pubs.naruc.org/pub/47AD30DC-1866-DAAC-
99FB-975A60906D6B.

APS. 2017. "Resource Comparison Proxy Plan of Administration, Arizona Corporation Commission Dockets No.
E-01345A-16-0036 and E-01345A-16-0123." Arizona Public Service Commission.

https://images.edocket.azcc.gov/docketpdf/0000182181.pdf.

AZCC. 2017. "Opinion and Order: Decision No. 26295 (Docket No. E-01345A-16-0036 In the Matter of The

Application of Arizona Public Service Company for a Hearing to Determine the Fair Value of the Utility
Property of the Company for Ratemaking Purposes, to Fix a Just and Reasonable Rate of Return
Thereon, to Approve Rate Schedules Designed to Develop Such Return, and Docket No. E-01345A-16-
0123 In the Matter of Fuel and Purchased Power Procurement Audits for Arizona Public Service
Company)." Arizona Corporation Commission.
https://docket.images.azcc.gov/0000182160. pdf?i=1642797977461.

CAISO. 2016. "What the Duck Curve Tells Us about Managing a Green Grid." California Independent System

Operator, https://www.caiso.com/documents/flexibleresourceshelprenewables_fastfacts.pdf.

CLICC. 2021. "Reply Brief of the California Low-Income Consumer Coalition, CPUC Order Instituting Rulemaking
to Revisit Net Energy Metering Tariffs Pursuant to Decision 16-01-044, and to Address Other Issues
Related to Net Energy Metering." California Low-Income Consumer Coalition.
https://docs.cpuc.ca.gov/PublishedDocs/Efile/G000/M407/K765/407765393.PDF.

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CPUC. 2020. "Resolution E-5165. Approval, with Modifications, of Vehicle-to-Grid Implementation Plans and
Technical Requirements in Compliance with Decision 20-09-035." California Public Utilities
Commission.

https://docs,cpuc.ca.gov/PublishedDocs/Published/G000/M411/K454/411454S54.PDF#:~:text=ln%20
Decision%2020-09-

035%2Cathe%20California%20Public%20Utilitiespathway.Commission%20%28CPUC%29%20adopted,p
ilots%2C%20temporarily%2C%20from%20Rule%2021%20smart%20inverter%20requirements.

	. 2021a. "Utility Costs and Affordability of the Grid of the Future an Evaluation Of Electric Costs, Rates

and Equity Issues Pursuant To P.U. Code Section 913.1." California Public Utilities Commission.
https://www.cpuc.ca.gOv/-/media/cpuc-website/divisions/office-of-governmental-affairs-
division/reports/2021/senate-bill-695-report-2021-and-en-banc-whitepaper_final_04302021.pdf.

	. 2021b. "Draft Distributed Energy Resources Action Plan, Aligning Vision and Action." California Public

Utilities Commission. https://www.cpuc.ca.gOv/-/media/cpuc-website/divisions/energy~
division/documents/distributed-energy-resources-action-plan/draft-der-action~plan-20-public.pdf.

	. 2021c. "Order Instituting Rulemaking to Consider Streamlining Interconnection of Distributed Energy

Resources and Improvements to Rule 21 (Proceeding R1707007)." California Public Utilities
Commission. December 15, 2021.

https://apps.cpuc.ca.gov/apex/f?p=401:56:0::MO:RP,57,RIR:P5_PROCEEDING_SELECT:R1707007.

	. n.d. "Rule 21 Interconnection." California Public Utilities Commission. Accessed January 21, 2022.

https://www.cpuc.ca.gov/Rule21/.

DOE. 2016. "Advanced Metering Infrastructure and Customer Systems." U.S. Department of Energy.

https://www.energy.gov/sites/prod/files/2016/12/f34/AMI%20Summary%20Report_09-26-16.pdf.

	. n.d. "Public Utility Regulatory Policies Act of 1978 (PURPA)." U.S. Department of Energy, Office of

Electricity. Accessed January 24, 2022. https://www.energy.gov/oe/services/electricity-policy-
coordination-and-implementation/other-regulatory-efforts/public.

EIA. 2020. "Annual Electric Power Industry Report, Form EIA-861 Detailed Data Files." U.S. Energy Information
Administration, https://www.eia.gov/electricity/data/eia861/.

	. 2021a. "Electric Power Monthly, Table 6.2.B. Net Summer Capacity Using Primarily Renewable Energy

Sources and by State, June 2021 and 2020 (Megawatts)." U.S. Energy Information Administration
https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_02_b.

	. 2021b. "Electric Power Annual 2020: Table 4.3. Existing Capacity by Energy Source, 2020 (Megawatts)."

U.S. Energy Information Administration.

https://www.eia.gov/electricity/annual/html/epa_04_03.html.

EPA. 2018. "Quantifying the Multiple Benefits of Energy Efficiency and Renewable Energy: A Guide for State
and Local Governments." U.S. Environmental Protection Agency.

https://www.epa.gov/statelocalenergy/quantifying-multiple-benefits-energy-efficiency-and-
renewabie-energy-guide-state.

	. 2020. "RE-Powering America's Land Initiative: Project Tracking Matrix." U.S. Environmental Protection

Agency, https://www.epa.gov/sites/default/fiies/2020-
10/documents/repowering_tracking_matrix_october_2020_508.pdf.

EPRI. n.d. "Distribution Resource Integration and Value Estimation (DRIVE)." Electric Power Research Institute.

Accessed January 24, 2021. https://www.epri.com/pages/sa/drive.

FERC. 2018. "An Overview of the Federal Energy Regulatory Commission and Federal Regulation of Public
Utilities." Federal Energy Regulatory Commission, https://ferc.gov/sites/default/files/2020-
07/fercl01.pdf.

	. 2020a. "Order Dismissing Petition for Declaratory Order Re New England Ratepayers Association under

EL20-42. Commissioner McNamee Is Concurring with a Separate Statement Attached."

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and Energy Program

https://www.ferc.gov/sites/default/files/2020-07/07-2020-E-2.pdf.

	. 2020b. "Petition for Declaratory Order of New England Ratepayers Association under EL20-42." Federal

Energy Regulatory Commission. https://elibrary,ferc.gov/eLibrary/docinfo?document_id=14851599.

	. 2020c. "Standard Interconnection Agreements and Procedures for Small Generators." Federal Energy

Regulatory Commission. August 20, 2020. https://www.ferc.gov/industries-data/electric/electric-
transmission/generator-interconnection/standard-interconnection.

	. 2020d. "FERC Affirms, Clarifies PURPA Final Rule." Federal Energy Regulatory Commission. November

19, 2020. https://www.ferc.gov/news-events/news/ferc-affirms-clarifies-purpa-final-rule.

	. 2020e. "Item E-2: Commissioner Richard Glick Dissent in Part Regarding Qualifying Facility Rates and

Requirements (Order No 872-A)," Federal Energy Regulatory Commission, https://www.ferc.gov/news-
events/news/item-e-2-commissioner-richard-glick-dissent-part-regarding-qualifying-facility.

	. 2020f. "Order No 872-A, Final Rule; Order Addressing Arguments Raised on Rehearing and Clarifying

Prior Order in Part." Federal Energy Regulatory Commission, https://www.ferc.gov/media/order-no-
872.

FERC 132. 2010. "Order on Petitions for Declaratory Order, Docket Nos. EL10-64-000 and EL10-66-000."

Federal Energy Regulatory Commission.

https://www.dwt.com/files/Uploads/Documents/Advisories/10-10_CAISO_0715.pdf.

FERC 842. 2018. "FERC Order No. 842, Essential Reliability Services and the Evolving Bulk-Power System-
Primary Frequency Response." Federal Energy Regulatory Commission.

https://www.ferc.gov/sites/default/files/2020-06/0rder-842.pdf.

FL PSC. 2021. "Florida PSC Approves Duke's Clean Energy Connection Program." State of Florida Public Service

Commission. January 5, 2021. http://www.psc.state.fi.us/Home/NewsLink?id=11905.

GTM. 2017a. "Rooftop Solar in Oahu Crashes With Loss of Net Metering, Lack of Self-Supply Installs."

Greentech Media, February 7, 2017. https://www.greentechmedia.com/articles/read/rooftop-solar-in-
hawaii-crashes-with-loss-of-net-metering-lack-self-supply.

	. 2017b. "Nevada's New Solar Law Is About Much More Than Net Metering." Greentech Media, June 16,

2017. https://www.greentechmedia.com/articles/read/nevadas-new-solar-law-is-about-much-more-
than-net-metering.

	. 2019. "Hawaii's Trailblazing Solar Market Continues to Struggle Without Net Metering." Greentech

Media, August 7, 2019. https://www.greentechmedia.com/articles/read/hawaiis-soiar-market-
continues-to-struggle-without-net-metering.

Hawaiian Electric, n.d. "Customer Renewable Programs: Smart Export." Hawaiian Electric Company. Accessed
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programs/private-rooftop-solar/smart-export.

HodgsonRuss. 2021. "Aimed at Improving Fairness in Cost Allocation and Reducing Barriers to New Renewable
Generation, the Public Service Commission Approves a New Interconnection Cost-Sharing
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publications-13422.html.

ICF. 2016. "Integrated Distribution Planning." ICF International.

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20Planning%208312016.pdf.

	. 2018. "Review of Recent Cost-Benefit Studies Related to Net Metering and Distributed Solar." ICF

International,

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%20FINAL_Revised%208-27-18.pdf.

IL CUB. 2020. "ICC Sides with CUB, Ameren's Net Metering Credits Continue." Citizens Utility Board of Illinois
December 18, 2020. https://www.citizensutilityboard.org/blog/2020/12/18/icc-sides-with-cub-

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amerens-riet-metering-credits-continue/.

IREC. 2018. "The Evolution of Hosting Capacity Analysis as a Grid Modernization Tool." Interstate Renewable
Energy Council, https://irecusa.org/blog/regulatory-engagement/the-evolution-of-hosting-capacity-
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	. 2019. "What Grid Transparency Looks Like." Interstate Renewable Energy Council. August 20, 2019.

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	. 2020. "Steps to Success: A Decision Making Framework for Implementing Hosting Capacity Analyses

(HCA), Interstate Renewable Energy Council. Filed with the Colorado Public Utilities Commission under
Proceeding Number 19M-0670E Distribution System Planning." Presented at the Colorado Public
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Kavlak, G., J. McNerneya, and J, Trancik. 2018. "Evaluating the Causes of Cost Reduction in Photovoltaic
Modules." Energy Policy 123 (December): 700-710. https://doi.Org/10.1016/j.enpol.2018.08.015

LBNL. 2017. "Putting the Potential Rate Impacts of Distributed Solar into Context." LBNL-1007060. Lawrence
Berkeley National Laboratory, https://emp.lbl.gov/publications/putting-potential-rate-impacts/.

Low-Income Solar. 2018. "Community Solar: Colorado." Low-Income Solar Policy Guide. May 2018.
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MA DOER. 2020. "Solar Massachusetts Renewable Target (SMART) Program." Massachusetts Department of
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	. n.d. "Solar Massachusetts Renewable Target (SMART)." Massachusetts Department of Energy

Resources. Accessed April 2, 2022. https://www.rnass.gov/solar-rnassachusetts-renewable-target-
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MA DPU. 2009. "Order Adopting Model Net Metering Tariff, DPU 09-03-A (8/20/2009)." Massachusetts
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MA S.9. 2021. Bill S.9, An Act Creating a next-Generation Roadmap for Massachusetts Climate Policy.
https://malegislature.gov/Bills/192/S9.

MA S.1979. 2016. An Act Providing for the Establishment of a Comprehensive Adaptation Management Plan in
Response to Climate Change. https://malegislature.gov/Bills/189/S1979.pdf.

Maninder, P.S., C. Tessum, I. Azevido, and J. Marshall. 2019. "Fine Particulate Air Pollution from Electricity
Generation in the US: Health Impacts by Race, Income, and Geography." Environmental Science &
Technology 53 (23): 14010-19. https://doi.org/10.1021/acs.est.9b02527.

ME PUC. 2015. "Maine Distributed Solar Valuation Study." Maine Public Utilities Commission.
https://www.nrcm.org/wp-content/uploads/2015/03/MPUCValueofSolarReport.pdf.

MN PUC. 2018. "Order Establishing Updated Interconnection Process and Standard Interconnection

Agreement. In the Matter of Updating the Generic Standards for the Interconnection and Operation of
Distributed Generation Facilities Established Under Minn. Stat. § 216B.1611. Docket No. E-999/CI-01-
1023 and Docket No. E-999/CI-16-521." Minnesota Public Utilities Commission.
https://mn.gov/puc/edockets/

NARUC. 2021. "State Approaches to Intervener Compensation." National Association of Regulatory Utility
Commissioners. https://pubs.naruc.org/pub/B0D6BlD8-1866-DAAC-99FB-0923FA35EDlE.

National Academies of Sciences, Engineering, and Medicine. 2022. "The Role of Net Metering in the Evolving
Electricity System." National Academies of Science, Engineering, and Medicine. 2022.
https://www.nationalacademies.org/our-work/the-role-of-net-metering-in-the-evolving-electricity-
system#sectionWebFriendly.

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National Grid. n.d. "Rhode Island System Data Portal/' National Grid. Accessed January 19, 2022.

https://www.nationalgridus.com/Business-Partners/RI-System~Portal.

NCCETC. 2021. "The 50 States of Solar: Net Metering Reforms Lead Solar Policy Activity in 2020." NC Clean

Energy Technology Center. January 27, 2021. https://nccleantech.ncsu.edu/2021/01/27/the-50-states-
of-solar-net-metering-reforms-lead-solar-policy-activity-in~2020/.

NCSL. 2017. "State Net Metering Policies." National Conference of State Legislatures.

https://www.ncsl.org/research/energy/net-metering-policy-overview-and-state-legislative-
updates.aspx.

NCSL and NASEO. 2017. "Here Comes the Sun: A State Policy Handbook for Distributed Solar Energy." National
Conference of State Legislatures and National Association of State Energy Officials.

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%20July%202017.pdf.

NESP. 2020. "National Standard Practice Manual For Benefit-Cost Analysis of Distributed Energy Resources."
National Energy Screening Project, https://www.nationalenergyscreeningproject.org/wp-
content/uploads/2020/08/NSPM-DERs_08-24-2020.pdf.

NREL. 2016. "Midmarket Solar Policies in the United States: A Guide for Midsized Solar Customers." NREL/TP-
6A20-66905. National Renewable Energy Laboratory, https://www.nrel.gov/docs/fyl6osti/66905.pdf.

	. 2018a. "Ten Years of Analyzing the Duck Chart: How an NREL Discovery in 2008 Is Helping Enable More

Solar on the Grid Today." National Renewable Energy Laboratory. February 26, 2018.
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	. 2018b. "The Cost of Distribution System Upgrades to Accommodate Increasing Penetrations of

Distributed Photovoltaic Systems on Real Feeders in the United States." NREL/TP-6A20-70710.

National Renewable Energy Laboratory, https://www.nrel.gov/docs/fyl8osti/70710.pdf.

	. 2021a. "U.S. Solar Photovoltaic System and Energy Storage Cost Benchmark: Q1 2020." NREL/TP-6A20-

77324. National Renewable Energy Laboratory, https://www.nrel.gov/docs/fy21osti/77324.pdf.

	. 2021b. "Sharing the Sun: Community Solar Deployment, Subscription Savings, and Energy Burden

Reduction." NREL/PR-6A20-80246. National Renewable Energy Laboratory.
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	. 2021c. "Fall 2021 Solar Industry Update NREL/PR-7A40-S1325." National Renewable Energy

Laboratory, https://www.nrel.gov/docs/fy22osti/81325.pdf.

NRRI. 2019. "Review of State Net Energy Metering and Successor Rate Designs." National Regulatory Research
Institute. https://pubs.naruc.org/pub/A107102C-92E5-776D-4114-9148841DE66B.

RAP. 2021. "Health Benefits by the Kilowatt-Hour: Using EPA Data to Analyze the Cost-Effectiveness of
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SEIA. 2021. "Arizona Solar, Data Current Through: 0.4 2021." 2021. https://www.seia.org/state-solar-
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Synapse, RAP, and Community Action. 2020. "Energy Infrastructure: Sources of Inequities and Policy Solutions
for Improving Community Health and Wellbeing." Synapse Energy Economics, Regulatory Assistance
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UT PSC. 2017. "Order Approving Settlement Stipulation, Docket No. 14-035-114 (Investigation of the Costs and
Benefits of PacifiCorp's Net Metering Program)." Public Service Commission of Utah.
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	. 2020. "Order, Docket No. 17-035-61, Application of Rocky Mountain Power to Establish Export Credits

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for Customer Generated Electricity." Public Service Commission of Utah.

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Utility Dive. 2018. "How Two Value-of-Solar Studies Add up to No Clear Value of Solar." Utility Dive. May 10,

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solar/522892/#:~:text=An%20April%2010%20draft%20study,kWh%20and%20about%20%240.41%2Fk
Wh.

VA H.B. 1526. 2020. Virginia Clean Economy Act. https://lis.virginia.gov/cgi-

bin/legp604.exe?201+sum+HB1526.

VA H.B. 1634. 2020. Shared Solar Programs. https://lis.virginia.gov/cgi-bin/legp604.exe?201+sum+HB1634.
Verdant. 2021. "Net-Energy Metering 2.0 Lookback Study." Verdant Associates, https://www.cpuc.ca.gov/-
/media/cpuc-website/divisions/energy-division/documents/net-energy-metering-
nem/nemrevisit/nem-2_lookback_study.pdf.

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A PQA U.S. Environmental Protection Agency
t lTr\ Office of Atmospheric Programs

Climate Protection Partnerships Division
1200 Pennsylvania Ave, NW(6202A)
Washington, DC 20460

www.epa.gov/statelocalenergy

EPA-430-R-22-004

2022

State and Local Climate
and Energy Program


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