Refers to on-site projects that connect to a customer’s site behind a customer’s electricity meter, thereby reducing the electricity that the customer needs to buy from the grid.

Bundled Renewable Energy Certificates (RECs)

An electricity product where Renewable Energy Certificates (RECs) are purchased alongside the delivery of the associated electricity.

Community Choice Aggregation (CCA)

Programs that allow local governments to purchase electricity for their community either directly or from third parties while the traditional utility provider continues to manage energy transmission, distribution systems, and billing. ​

Also known as: Municipal Aggregation, Government Energy Aggregation

Community Solar

Mid-sized solar projects (e.g., up to 2MW) sited within the customers’ utility service territory and connected to the distribution grid. The output of the solar array is divided among multiple subscribers, who receive utility bill credits for their share of the energy production. Typically, the utility or a third party develops and maintains the plant on behalf of the subscribers. Community Solar is a subset of Community Renewable projects that cover a larger set of renewable resources.

Also known as: Community Shared Solar, Shared Solar

Electric Retail Choice Market

Markets where customers have been granted, at the state level, the right to procure energy from a competitive electricity supplier other than their traditional utility provider.

Also known as: Competitive Retail Electricity Market, Deregulated Retail Market, Restructured Market, Direct Access Market

Energy Burden

Per the Initiative for Energy Justice, energy burden refers to: “the expense of energy expenditures relative to overall household income.” While there are no universally accepted thresholds for what constitutes a high energy burden, some papers have proposed thresholds such as 6-11% of household income or suggested relative measures (e.g., households with high energy burden are those with values above the median for the local community).

Energy Justice

Per the Initiative for Energy Justice, energy justice refers to: “the goal of achieving equity in both the social and economic participation in the energy system, while also remediating social, economic, and health burdens on those historically harmed by the energy system (‘frontline communities’).”

Energy Poverty

Per The World Bank, energy poverty is: “the state of being deprived of certain energy services or not being able to use them in a healthy, convenient, and efficient manner, resulting in a level of energy consumption that is insufficient to support social and economic development.”

Energy Security

Per the IEA, energy security is: “the uninterrupted availability of energy sources at an affordable price.”

Green Pricing Program

A utility product that enables customers to voluntarily procure renewable energy equivalent to a portion or all of their electricity needs, typically at a price premium. Green pricing programs are often targeted at residential and small commercial customers. Typically, the utility retires the RECS associated with the renewable energy on behalf of the customer.

Also known as: Green Power Program

Green Tariff

A utility tariff or electricity rate, which allows a class of customers to source a portion or all of their electricity from new renewable energy projects typically through long term contracts, with the customer purchasing both the electricity from a renewable energy project and the associated RECs. Typically, these programs are designed for large customers.

Also known as: Renewable Energy Tariff

Integrated Resource Plan (IRP)

An integrated resource plan is a utility plan for meeting forecasted annual peak and energy demand, plus some established reserve margin, through a combination of supply-side and demand-side resources over a specified future period.

Investor Owned Utility (IOU)

A privately-owned electric utility that is subject to state regulation and financed by a combination of shareholder equity and bondholder debt that operate for profit.

Kilowatt (kW)

A measure of power which is equal to 1,000 watts.

Kilowatt-hour (kWh)

A measure of energy which is equal to 1,000 watts being used or generated for one hour.

Long-Term REC Purchase

Long-term renewable energy certificate (REC) purchases are the renewable energy certificate procurement tied to a specific project with a contract of at least five years.

Megawatt (MW)

A measure of power which is equal to 1,000,000 watts or 1,000 kilowatts.

Megawatt-hour (MWh)

A measure of energy which is equal to 1,000,000 watts or 1,000 kilowatts being used or generated for one hour.

Municipal Utility

An electric utility owned by a city or region that operates not for profit.

Also known as: City Owned Utility and often shortened to Muni.

On-Site Solar

Solar project(s) built on local buildings or land, at the same location where the energy is consumed.

Organized Wholesale Market

The purchase and sale of electricity from generators to resellers, along with the ancillary services needed to maintain reliability and power quality at the transmission level. Resellers include electricity utility companies, competitive power providers and electricity marketers.

Physical PPA

A power purchase agreement (PPA) in which the seller delivers electricity to the customer (on-site) or a predetermined delivery point within their local electricity markets (off-site) who takes legal title to the energy. Physical PPAs can be used where allowed by state law.

Also known as: Direct PPA

Power Purchase Agreement (PPA)

A contract with an energy project through which a customer agrees to purchase the energy produced by a generator over a specified period at a predetermined price per unit of energy. Types of PPAs include Physical PPAs, Financial PPAs and other structures.

Regional Transmission Operators or Independent System Operators (RTOs/ISOs)

Independent, membership-based, not for profit organizations that ensure reliability and optimize supply and demand bids for wholesale electric power. Areas within RTOs/ISOs are considered to be Organized Wholesale Markets.

RTOs and ISOs are often used interchangeably although there are small differences. In our materials, we use RTO often to refer to both.

Renewable Energy Certificates (RECs)

A REC represents the clean energy attributes of 1 MWh of renewable electricity and conveys the environmental and social attributes of the generated electricity to customers.

Renewable Portfolio Standards

State legislated mandates that require utilities to use or procure renewable energy or renewable energy credits (RECs) to account for a certain percentage of their retail electricity sales — or a certain amount of generating capacity — according to a specified schedule. Renewable portfolio goals are similar to RPS policies, but not legally binding.

Request for Information (RFI)

A solicitation process to obtain general information on energy products, services or suppliers with intent of gaining a better understanding of the marketplace.

Request for Proposals (RFP)

A solicitation process, often through competitive bidding, to obtain supplier proposals with the intent to contract for procurement.

Rural Electric Cooperative

An electric utility cooperatively owned by the customers and governed by a board of directors, with some oversight by state regulators.

Also known as: Electric Cooperative, Cooperative Utility


The conditions, such as pricing, charged to customers for the delivery and consumption of electric power, or the on-site generation of electricity.

Also known as: Electric Rate Schedule

Third-Party On-Site Solar PPA

State authorization of Third-Party On-Site Solar PPAs allows residential customers to purchase electricity generated by solar panels on their roof from a third party that owns the PV system.

Transmission System

A system that delivers electricity from generators to an electric substation; this is the second stage in the delivery of energy.

Unbundled Renewable Energy Credits (RECs)

An electricity product where customers purchase RECs separate from the associated electricity.

Virtual Net Metering

A process which allows customers to get credited for solar installations that are not on-site. Customers contract for projects or portions of projects within their utility load zone, but off their property, and are credited by the utility for the power that that project delivers to the grid.

Also known as: Remote Net Metering

Virtual Power Purchase Agreement (VPPA)

A financial agreement in which a customer agrees to pay a predetermined price for the generated electricity and, typically, the renewable attributes (RECs) from a renewable energy project. Instead of the customer receiving the electricity physically, the project owner sells the energy into the local organized wholesale market; for each MWh, the buyer then pays or receives the difference between the wholesale market revenue and the predetermined PPA price.

Also known as: Contract for Differences, Synthetic PPA, Financial PPA