• Alternating current

    An electric current which periodically reverses direction and changes its magnitude continuously with time. In an alternating current, the voltage periodically changes from positive to negative and vice versa.

  • Area median income

    The household income for the median household in each region is also called the Median Family Income (MFI).

  • Avoided cost

    The incremental cost to a utility associated with generating or purchasing electric energy or capacity, in an amount equal to that purchased from the qualifying facility.


  • Bill credit values

    The credit community solar subscribers receive for the electricity their share of the project generates. The value of this credit can vary. Types of bill credits are Full Retail/Retail Rate, Value-of-Solar, and Supply-only/Avoided Cost.


  • Canopy installation

    Elevated structures on which solar panels are installaed that provide usable space underneath, usually in the form of parking lots or other paved areas. 

  • Carve-outs (LMI inclusion)

    The segment of a state's Renewable Portfolio Standard (RPS) mandates a specific target for the percent or amount of electricity generated from a community solar panel that LMI subscribers offtake. Solar carve-outs vary by state. A project may set its own carve-out higher than the state's requirement or independently set one if it does not mandate a carve-out.

  • Community development entities (CDEs)

    A domestic corporation or partnership that is an intermediary vehicle for the provision of loans, investments, or other financial opportunities for low-income communities.

  • Community solar

    A method for sharing the value of solar power generated from a single PV system with more than one electricity user. Community solar typically creates new access to PV energy for those who cannot install PV residentially due to a lack of home ownership, or because of inadequate roofing.

  • Community-scale solar

    A solar project which provides electricity for commercial or community consumption, compared to residential solar which typically powers a single home.

  • Cooperative utility (Coop)

    Community-centered electricity utilities owned, controlled, and run by and for their members.


  • Demand charge

    A monthly fee paid by a subscriber to help maintain the delivery of electricity to their building. The fee goes towards the cost of maintaining the electric utility's infrastructure.

  • Deregulated electricity market

    A utility market that allows for the entrance of competitors to buy and sell electricity. Market participants are permitted to invest in power plants and transmission lines.

  • Direct current

    An electric current in which the direction of the voltage is constant. Solar rays shining on solar panels stimulate the flow of electrons in the same direction.


  • Electric utility

    See Utility

  • Electrical grid

    An integrated system of electricity distribution, usually covering a large area.

  • Enabling legislation

    State legislation that allows third parties to develop and enroll customers in community solar installations.

  • Energization

    See Year Energized

  • Energy burden

    The ratio of energy expenditures to overall household income.

  • Energy credit incentive

    See Energy rebate program

  • Energy rate

    The price paid for each unit of electricity supplied.

  • Energy rate average

    A state's average cost of a kilowatt hour (kWh).

  • Energy rebate program

    An energy incentive program that provides a cash rebate for customers planning to install new solar, energy efficient equipment, or cooling systems in/on their homes.


  • Federal poverty level

    A measure of income issued every year by the Department of Health and Human Services (HHS) to determine eligibility for certain programs and benefits, such as savings on Marketplace health insurance, and Medicaid and CHIP coverage.

  • Full retail rate

    The energy rate non-solar subscribers pay per kilowatt hour (kWh) for their electricity. If a subscriber has extra energy to sell back to the grid, they receive the full cost of the electricity.


  • Gigawatt (GW)

    A unit of power equal to one billion watts; one million kilowatts, or 1,000 megawatts.

  • Grid

    See Electrical grid

  • Grid-connected solar energy systems

    A PV system connected to an electric circuit served by an electric utility company.

  • Ground-mounted installation

    A free-standing solar array mounted on the ground using either a rigid metal frame or atop a single pole. 


  • Income-eligible only

    A method of determining if subscribers qualify as LMI - to meet carve-outs or mandates, and to receive specific LMI project benefits - based on income requirements such as AMI or FPL.

  • Installation name

    The distinct name of a specific installation. Multiple installations may be part of a community solar project.

  • Installation type

    How solar arrays are installed - whether roof, ground, canopy, or combination.

  • Interconnection

    The approval process by which utilities study a solar project to identify any potential impacts it will have on the grid.

  • Interconnection costs

    The costs incurred by the electric utility while installing and maintaining the physical facilities necessary to interconnect a community solar installation. These include costs associated with connection, switching, metering, transmission, distribution, safety provisions, and administrative costs.

  • Inverter

    A device that converts direct current electricity to alternating current either for stand-alone systems or to supply power to an electricity grid.

  • Investment Tax Credit (ITC)

    A federal tax incentive for business or personal investment that can be applied to solar installations. The ITC lets individuals or businesses deduct a certain percentage of their solar investment costs from their taxes.

  • Investor-owned utility (IOU)

    Large electricity distributors owned by stockholders that typically seek to maximize profits.


  • Levelized Cost of Energy (LCOE)

    The cost of energy generated from a PV system based on the system's installed price, its total lifetime cost, and its lifetime electricity production. That is, LCOE as a measure of the average net present cost of electricity generation for a generator over its lifetime.

  • Life-cycle cost

    The estimated cost of owning and operating a PV system for its lifetime.

  • Lifetime

    The period during which a system can operate above a specified performance level.

  • LMI community solar

    Any community solar project mandated to serve LMI households, whether through income eligibility or carve-out requirement. Typically, these create new access to communities that do not have the ability to participate in existing low-income PV programs (residential), or existing community solar programs that do not prioritize LMI inclusion.

  • LMI customer savings percent

    The percentage of savings an LMI customer receives. Typically determined as a savings per kWh, i.e. community solar rate subtracted from the utility rate, divided by the utility rate.

  • LMI requirement

    The mechanism through which a project requires LMI inclusion. Carve-outs and income-eligibility are the most common mechanisms.

  • LMI share of capacity

    The share (percentage) of the overall capacity of the installation dedicated to serving LMI households.

  • Low- to-Moderate-Income (LMI) / Low- and Moderate-Income

    Households, defined as having income levels lower than 80% of the Area Median Income (AMI).


  • Modified Accelerated Cost Recovery System (MACRS)

    A depreciation system used for tax purposes that allows the capitalized cost of an asset to be recovered over a specified period via annual deductions. 

  • Municipally-owned utility (Muni)

    A utility owned, operated, and controlled by a city's public offices.


  • Net Metering

    A billing mechanism that credits solar energy system owners for the electricity they add to the grid.

  • Net present value

    A method of calculating the return of an investment.

  • New Markets Tax Credit (NMTC)

    A program that attracts private capital into low-income communities by allowing private individual and corporate investors to receive a tax credit against their federal income tax in exchange for making equity investments in specialized financial intermediaries called Community Development Entities (CDEs). 


  • Operational projects

    A community solar project that is in operation (energized).


  • Photovoltaic (PV) system

    See Solar energy systems

  • Photovoltaic(s) (PV)

    The direct conversion of light into electricity.

  • Pilot program/project

    A small-scale preliminary community solar program or project implemented to evaluate feasibility, duration, cost, and challenges associated with a novel community solar project. Pilot programs/projects are meant to improve upon the overall concept and design in its ability to expand access to renewable energy. In the context of the LIFT Toolkit, expansion for LMI households.

  • Program name

    The name of the program providing funding and/or managing the qualifications and requirements of participating projects.

  • Project capacity

    The overall capacity of a specific installation as indicated by a nameplate capacity in Alternating Current (AC) or Direct Current (DC).

  • Project developer or owner

    The name of the legal entity that developed or owns the community solar project.


  • Regulated electricity market

    Markets that are typically vertically integrated; the utility is responsible for generation, transmission, and distribution of electricity. This often allows utilities to operate as a monopoly that creates, delivers, and sells electricity to its customers.

  • Regulatory structure

    Whether a state is a regulated or deregulated market structure.

  • Renewable Energy Certificate (REC)

    A market-based instrument that represents the property rights to the environmental and social attributes of renewable electricity generation. RECs are issued when one megawatt-hour (MWh) of electricity is generated and delivered to the electricity grid from a renewable energy resource. 

  • Renewable Energy Credit (REC)

    See Renewable Energy Certificate

  • Residential solar

    Compared to community solar, residential solar is typically installed on, and powers a single home.

  • Retail rate

    The utility bill credit generated by solar energy that is valued at the rate a customer pays for their electricity or at a one-to-one rate.

  • Rooftop installation

    Solar panels installed on the roofs of residential, commercial, or institutional buildings.


  • Solar energy systems

    A device or group of devices and a structural design feature that uses PV or mirroring technology to provide for the collection, generation, storage or distribution of solar energy for electricity, heating or cooling.

  • Solar panels

    Crystalline silicon type solar cells used for converting sunlight into electrical energy either through PV panels or through mirrors that concentrate solar radiation. 

  • Subscriber

    Users of community solar systems.

  • Supply-only / Avoided Cost

    The utility bill credit generated by solar energy that is valued at the rate the utility would have paid to purchase electricity from another source. This credit is typically a much lower bill credit value than retail rate or value of solar.

  • System size

    See Project capacity


  • Tax Benefits

    Benefits that are available to project developers through the renewable energy Investment Tax Credit (ITC) or depreciation.


  • Utility

    A company that engages in the generation and/or distribution of electricity. Utilities are organized primarily into three types: Investor-Owned, Municipally-Owned, or Cooperative utilities.

  • Utility-scale solar

    Large-scale solar power generated either from a PV power station or concentrated solar power, that represents a significant portion of a utility's overall capacity, and meets a minimum defined threshold of 1 MW. The industry standard for this threshold varies: Solar Energy Industries Association (SEIA) = 1 MW; The National Renewable Energy Laboratory (NREL) = 5 MW.


  • Value of solar

    The utility bill credit generated by solar energy that is valued at a one-to-one rate and which includes additional compensation mechanisms for other grid services that solar energy provides, such as demand reduction or environmental and other benefits.

  • Value stack

    A system of stacking monetary value to the kWh of the overproduction of an electrical system. Some states offer net metering programs while other states offer a value stack to determine tariffs, bill credit rates, REC values, or other incentive values. 


  • Year energized

    The year the project was energized and produced energy for the first time.