Renewable Energy Glossary

A guide to terms and concepts



A type of fuel produced by biomass. Examples include ethanol and biodiesel.


Biomass includes biological materials that were alive or created during our lifetimes, and it is considered a renewable energy source. Examples include wood, corn, and animal manure. Biomass can be used as a fuel directly, or it can be converted into a biofuel such as ethanol or biodiesel.

Community Power

Community Power, also referred to as “community choice aggregation,” enables a local government to aggregate the electricity demand of customers within its jurisdiction to procure power from an alternative supplier. The utility continues to provide transmission and distribution services. In NH, Community Power was established with the passage of Senate Bill 286 during the 2019 legislative session and is governed by NH RSA 53-E. The most common reason for establishing a Community Power Program is the possibility of obtaining more competitive electricity rates than the utility; however, a growing number of local governments are pursuing Community Power as a way to increase the percentage of their electricity that comes from renewable energy sources.

Electric Vehicle (EV)

Electric vehicles (EVs) derive all or part of their power from electricity. There are several categories of EVs:

  • All-electric vehicles (AEVs) operate on electricity alone using batteries charged by an outside electric power source. They include battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs).
  • Plug-in hybrid electric vehicles (PHEVs) use batteries to power an electric motor and use another fuel, such as gasoline or diesel, to power an internal combustion engine or other propulsion source. Batteries can be charged by an outside electric power source, by the internal combustion engine, or through regenerative braking.
  • Hybrid electric vehicles (HEVs) are powered by an internal combustion engine and an electric motor. Batteries can be charged by the internal combustion engine or through regenerative braking, but not by an outside electric power source.

Electric Vehicle Supply Equipment (EVSE)

Electric Vehicle Supply Equipment, also known as electric vehicle charging stations, supply power to charge battery electric vehicles and plug-in hybrid electric vehicles. There are three types of EVSEs:

  1. Level 1 (120 volts AC): Delivers 2 to 5 miles* of driving range per hour of charge.
  2. Level 2 (240 volts, AC): Delivers 10 to 20 miles* of driving range per hour of charge. This requires equipment beyond at-home plug-ins.
  3. DC Fast Charge (480 volts DC and higher): Delivers 60 to 80 miles* of driving range in 20 minutes of charging. This requires special, high-powered equipment.
*Charging times vary based on how depleted the battery is, how much energy it holds, the type of battery, and the type of charging equipment.

Environmental Protection Agency (EPA)

The U.S. EPA is an independent federal agency that develops and enforces environmental regulations.

Energy Information Agency (EIA)

The U.S. EIA collects, analyzes, and shares independent and impartial statistics on energy. The EIA is part of the federal Department of Energy.

Federal Energy Regulatory Commission (FERC)

FERC is an independent federal agency that regulates the interstate transmission of natural gas, oil, and electricity.

Geothermal Energy

Energy produced by the internal heat of the earth. Geothermal energy can be used directly for heating or to produce electric power.

Greenhouse Gas (GHG)

Greenhouse gases trap heat in the atmosphere by absorbing infrared radiation. The increased concentration of greenhouse gases in the atmosphere increases the risk of climate change. Examples of GHGs include water vapor (H2O), carbon dioxide (CO2), methane (CH4), Nitrous oxide (N20), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

Hydroelectric Power

Electric energy made by the conversation of energy produced from water.

Investor-owned utilities (IOU)

Investor-owned utilities are owned by stockholders, which makes them private, for-profit companies. Investor utilities like Eversource can’t generate electricity; their role is to distribute electricity.

Net Metering

A contractual arrangement that permits an electrical utility customer to turn their electric meter backwards and sell any excess power generated (over and above their usage requirement) back to the electrical grid to offset some or all of their consumption.

Public Utilities Commission (PUC)

The New Hampshire PUC regulates electric, telecommunications, natural gas, water, and sewer utilities in New Hampshire.

Photovoltaic (PV) Cell

A photovoltaic (PV) cell is a device that generates electricity directly from sunlight.

Power Purchase Agreement (PPA)

A power purchase agreement (PPA) is a long-term contract between an energy buyer and the developer of a renewable energy project that hasn’t been built yet. Typically, the buyer guarantees that the developer will receive a fixed price for their energy, and in exchange, the buyer receives renewable energy credits (RECs) for every megawatt hour of clean energy that is generated and sold. This arrangement enables the project developer to secure long-term financing and build the project. In some PPAs, the generator and consumer are connected to the same grid, referred to as a physical PPA.

Renewable Energy Credit (REC)

Also called “Renewable Energy Certificate,” a REC represents the environmental benefits of producing 1,000 kWh (or one megawatt-hour) of electricity from a renewable energy source. When electricity customers purchase RECs, they can say they bought electricity generated from renewable sources. RECs are one and done: if they’re purchased or claimed once, they can’t be bought or claimed again.

Renewable Portfolio Standard (RPS)

New Hampshire has a renewable energy requirement. This year, in 2020, just about 20 percent of New Hampshire’s energy supply needs to come from renewable sources in the form of RECs. This requirement is called a renewable portfolio standard, shortened as RPS.

Solar Energy

Energy derived from the sun in the form of solar radiation. Electricity from the sun can be produced in two ways: photovoltaic electricity and solar thermal electricity.

Virtual Power Purchase Agreement (VPPA)

A virtual PPA is a purely financial contract where the energy is sold on the wholesale electricity market at a defined settlement location, and the buyer continues to get their electricity from their utility company at their utility’s rate.

Wind Energy

Energy available from the movement of the wind across a landscape. The sun's energy creates wind by heating the earth, oceans, and atmosphere.

Wind Turbine

Wind turbines are structures that use moving air to generate electricity (wind power) through the use of blades (called rotors) that are easily turned by the wind. This rotating motion is converted inside the turbine into an electric current, which is then interconnected to a nearby electric grid.

Renewable Energy

The City of Keene's ECC Committee recommends defining "renewable" energy specifically as green power sources that have the most environmental benefits and the fewest adverse impacts. Green power sources include wind, solar, biomass, geothermal, biogas, and low-impact hydropower.