biomass: Renewable organic matter such as wood, plants, and plant and animal waste.

British thermal unit (Btu): A measurement of energy, used to describe the energy content of a fuel (for example, a barrel of oil produces 5.8 million Btu).

carbon dioxide (CO 2): A trace gas in the atmosphere formed when carbon-containing fuels combine with oxygen in the air through combustion; it is believed to contribute to global warming.

crude oil: Unrefined liquid hydrocarbons found in underground reservoirs.

curie: A measurement of radioactivity.

electricity: An energy form in which charged particles move, creating a current.

electric utility: A private or public company that generates and distributes electrical energy to consumers.

emissions: Releases into the atmosphere.

fossil fuel: An energy source from decayed organic material that contains hydrocarbons and is formed in the earth's crust.

fuel cell: A device that generates electrical energy from a chemical reaction between hydrogen fuel...