Researching residential solar power systems means being introduced to a number of terms that you may or may not be familiar with, including net metering, avoided cost, or renewable portfolio mandate. But as you’re learning about your solar power options, it’s important that you understand these essential terms. In our solar power glossary, you’ll learn what some of the most common and important solar power terms mean.

  • Alternating current: A type of electrical current.
  • Array: Also known as a solar array, an array is a group of solar panels that are wired together.
  • Average retail electricity rate: The amount customers can expect to pay for a kilowatt hour of energy.
  • Avoided cost: The amount it would cost the utility to produce or purchase a unit of energy.
  • Azimuth: Angle measured clockwise from north indicating the angle between the north direction and the surface projection into the horizontal plane. For example, a 180 degree azimuth faces south.
  • Battery: A device that stores electricity. Typically only used for solar power systems that are stand alone or off grid.
  • Cell: A photovoltaic module unit that provides the materials necessary to produce electricity.
  • Clean energy: Energy that, when generated, does not cause harm to the environment. Closely tied to renewable energy, including solar energy.
  • Customer load: How much power your home uses.
  • Direct current: An electrical current type, the opposite of alternating current.
  • Electrical grid: The utility power grid. This is a system of electrical lines that transmit and distribute power.
  • Energy indepenence: The state of not relying on others for electricity. This can refer to home owners generating their own electricity, or range to cities, states, or the entire nation.
  • Excess energy: Typically referred to in net metering, excess energy in solar power is energy that is produced, but not used, in your home. In most residential solar power systems, excess energy is fed into the electrical grid for a net metering credit.
  • Financial incentives: Solar power financial incentives reduce the cost of installing solar power panels. They include solar power rebates, solar power tax incentives, solar power financing, solar power performance payments, and net metering.
  • Full retail rate: Often referred to in net metering, full retail rate is the amount of money consumers pay for a unit of energy. Utilities that reimburse net metering customers at the full retail rate will give them a credit that is equal to what they would have paid to purchase that energy.
  • Gigawatt (gW): A unit of electrical measure. One thousand megawatts, one million kilowatts, or one billion watts.
  • Grid connected photovoltaic capacity: The amount of solar energy installed and connected to the electrical grid.
  • Grid connected system: A residential solar power system creates its own energy and is connected to the grid, supplying excess energy to the utility.
  • Kilowatt (kw): A unit of electrical measure at a level of one thousand watts.
  • Kilowatt hour (kWh): One kilowatt of electricity supplied for an hour.
  • Megawatt (MW): One million watts, or one thousand kilowatts.
  • Meter: A device used to measure and record how much electricity a customer uses or generates.
  • Net metering: An agreement with your utility company that you will provide excess energy to the grid and receive credit for that energy on your electricity bill.
  • Off grid: Not connected to the utility power grid.
  • Photovoltaic (pv): Able to produce voltage when exposed to light.
  • Photovoltaic system: A full installation on photovoltaic modules and components used to produce solar power.
  • Property Assessed Clean Energy (PACE): A type of solar power financing, PACE offers home owners low cost, fixed loans tied to their property taxes. Home owners with PACE financing will pay back their loans as a special assessment on their property taxes.
  • Renewable energy: Energy that comes from a renewable resource, such as the sun. Often compared to non renewable energy, such as fossil fuels.
  • Renewable portfolio mandate: A state requirement that utilities source a certain percentage of their energy from renewable sources, often including solar power. Some states have a particular percentage of power that must come from solar as well.
  • Residential Renewable Energy Tax Credit: A 30% federal tax credit that provides solar power home owners with a rebate on their personal taxes. Currently good through 2016.
  • Residential solar power system: A photovoltaic array and connections installation that provides solar power to a home.
  • Solar access law: Laws that protect access to the sun for solar power. Most often, solar access laws forbid home owner’s associations from significantly interfering with the installation of a residential solar power system. Most states with solar access laws require that home owner’s associations not place restrictions on the installation of solar power that would make the system significantly less efficient or more expensive. May include (or be limited to) a solar easement.
  • Solar capacity: The amount of solar power installed in a particular home, city, state, or other location.
  • Solar easement: A voluntary agreement between property owners that guarantees unblocked access to the sun for solar power generation.
  • Solar energy: Energy generated from the sun.
  • Solar power: Energy, typically collected and used as electricity, that is generated by the sun.
  • Solar power financing: A loan or lease program that reduces the intial cost of solar power sytem installation.
  • Solar power performance payment: Through solar power purchase agreements, utilities purchase renewable energy credits (Solar Renewable Energy Certificates, or SRECs) from home owners with solar power systems. These payments do not require usage of the solar power, only credit for its generation, so home owners can collect these credits while using or selling solar power.
  • Solar power rebates: Typically offered by utilities or states, a solar power rebate offers cash back to home owners who have installed a residential solar power system.
  • Solar power system: An installation of a photovoltaic array and related connections.
  • Solar power tax incentives: Income tax credits, property tax exemptions, sales tax exemptions, and other tax advantages offered to residential solar power system owners.
  • Solar Renewable Energy Certificate (SREC): A renewable energy certificate that sells the credit for generating solar power. Typically used by utilities to meet their requirements for renewable energy mandates.
  • Surplus: Referred to in net metering, a surplus exists when a home owner continually generates excess energy that is sent back to the grid and does not need to purchase grid produced energy. In some states, home owners can receive their surplus energy credit as a cash payment, while others revert surplus credits to the utility after a specified period of time.
  • Technical potential: The amount of solar power that can be installed.
  • Utility: A company that produces and/or distributes consumer electricity regionally or in an entire state.
  • Utility scale photovoltaics: Utility solar power installations.
  • Watt: A unit of electrical measure.