Green Power: Definitions

This glossary includes key terms from the Guide and may be used as a companion to the text.



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Acid rain		acidic compounds caused by pollutants such as sulfur dioxide (SO2) and nitrogen oxides (Nox) that collect in the atmosphere, are absorbed by clouds, and create acidic rainfall
Anthropogenic greenhouse gas		greenhouse gas emitted as a result of human activities such as fossil fuel combustion, industrial processes, and agriculture
Average emission rate		average amount of conventional or greenhouse gas emissions on a weight per unit of output basis, such as tons of carbon dioxide (CO2) per megawatt hour of electricity produced from coal
Baseline		basic information gathered before a program begins that is used later to provide a comparison for assessing program impact
Baseline year		the particular year (or series of years) upon which a baseline is established and performance in subsequent years is compared
Bioaccumulate		process whereby harmful substances concentrate or magnify as they move up the food chain
Biogas		gas (primarily methane) released from decomposing biological material including animal, human, and agricultural waste
Biomass		biological materials, such as wood, grasses, and agricultural waste materials that can be burned to created heat and/or electricity
Carbon dioxide		a prevalent greenhouse gas, the atmospheric concentration of which is increasing due to human activities such as fossil fuel combustion
Carbon equivalency		method of converting volumes of greenhouse gases into equivalent volumes of carbon dioxide based on the global warming potential of the particular gas
Carbon-intensity		the total volume of carbon dioxide emitted per unit of output; e.g., the carbon intensity of electricity derived from coal is 2,200 pounds of carbon dioxide emitted per megawatt hour of electricity produced
Carbon offsets		reductions in carbon dioxide (or other greenhouse gases) that can be bought and sold in carbon markets and should be certified by third-parties
Clean energy		see "green power"
Clean energy block purchases		green power purchased in a fashion where each "block" represents a certain amount of power (e.g., 1 MWh) and purchasers buy a fixed number of blocks of power
CO2		see "carbon dioxide"
Coal		a plentiful fossil fuel widely used for heat and electricity that generation that emits carbon dioxide, sulfur dioxide, and mercury at the point of combustion and has causes a range of other life-cycle social and environmental problems
Compact fluorescent lamp (CFL)		fluorescent light bulb designed to replace incandescent light bulbs, see also "incandescent" and "fluorescent lighting"
Competitive market		deregulated electricity market where consumers can choose which company to buy power from
Concentrating solar		large-scale electricity generated by reflecting a sunlight onto a tube of material that becomes super-heated, boils water, and turns a turbine
Conventional air pollutants		gases including sulfur dioxide, nitrogen oxides, and mercury that cause problems on a local and regional scale
Conventional electricity		electricity produced in thermal power plants from coal, nuclear, natural gas, and oil
Decommissioning		official retirement, disassembly, and disposal of used coal and nuclear power plants
Deregulated		see "competitive markets"
EcoLogo		multi-attribute environmental certification managed by the Government of Canada
EcoPower Standard		standard for renewable energy certificates managed by Environmental Resources Trust, which separates the "green power" portion of the product from the "carbon offsets"
E-Grid database		comprehensive database of U.S. power plant fuel use, power production, and emissions - managed by the Environmental Protection Agency
Electricity service provider		company from which a customer buys electricity
Energy conservation		using less energy through means such as turning off lights, using powerstrips for office electronic equipment, and adjusting building thermostats
Energy efficiency		getting more work out of each unit of energy consumed, e.g., using compact fluorescent lights rather than incandescents, using EPEAT certfied computers rather than standard models, upgrading to ENERGY STAR heating and cooling systems
ENERGY STAR		energy efficiency standard managed jointly by the U.S. Environmental Protection Agency and Department of Energy
Energy subsidies		direct or indirect monetary support given to power companies from the federal government
Equity states (in green power generation)		investment of money resulting in partial ownership of green power generation assets such as a wind turbine
EPEAT		standard for responsible computers that lists over 500 models and is managed by the Green Electronics Council
Fluorescent lighting		gas-discharge lamps that require ballasts and use electricity to excite mercury vapor in argon or neon gas, producing ultraviolet light that causes a phosphor to fluoresce, producing visible light
Fossil fuel		combustable material with a high carbon content - primarily coal, natural gas, and petroleum - that is formed over thousands of years from decomposing biological materials and the earth's geological processes
Fossil fuel power plants		thermal power plants that produce electricity by burning fossil fuel
Generation assets		equipment such as thermal power plants, hydroelectric dams, wind turbines, and solar panels used to produce electricity
Geothermal		electricity produced in areas with geological features that allow access to heat emanating from the earth's core
GHG Protocol Corporate Standard		template for developing an institutional greenhouse gas inventory
Global warming		observed increase in average global temperature and change in sea level and weather patterns due to higher levels of greenhouse gas in the atmosphere
Greenhouse gas		heat-trapping gas in the Earth's atmosphere responsible for global warming; category includes water vapor, carbon dioxide, methane, ozone, CFCs, and nitrogen oxides
Green power		electricity produced from energy sources such as wind, solar, and geothermal, that are cleaner than conventional fuels and do not produce hazardous waste
Green power program		services offered buy utilities in regulated markets allowing customers to buy grid-delivered green power
Green Power Partnership		program of the U.S. Environmental Protection Agency that provides resources and recognition to institutional purchasers of green power
Green-e Energy		leading standard for green power managed by the Center for Resource Solutions
Grid-delivered		electricity produced within a buyer's region that is connected to the buyer via the electricity grid
Grid-delivered green power		green power produced within a buyer's region that is connected to the buyer via the electricity grid
Hazardous substance		1. material posing a threat to human health and/or the environment, that can be toxic, corrosive, ignitable, explosive, or chemically reactive, 2. substance that must be reported to the EPA if released into the environment.
Hg		see "mercury"
High-level radioactive waste		hazardous by-product of nuclear reactors, this material produces dangerous levels of radioactivity for thousands of years and requires specialized and secure long-term storage
Hydroelectric dams		electricity produced by building a dam on a river and controlling the flow of water through an electric turbine
Incandescent		inefficient lighting technology that produces light by passing an electrical current through a thin filament
In-situ leach mining		form of mining where water and chemicals are pumped through rocks to dissolve and extract uranium, sometimes causing ground water contamination
Intergovernmental Panel on Climate Change		leading international panel of scientists studying global warming causes, trends, and impacts
Inventory		collection of data on product use and impacts, which can include such data points as costs, emissions, and hazardous waste
Landfill gas		gas (primarily methane) that is produced from landfilled trash as a result of anaerobic decomposition - this gas can be captured and burned to create electricity
Large-scale hydro		hydroelectric power produced from large dams with a generating capacity greater than 20 megawatts (MW)
LED		light-emitting diode; high efficiency lighting that uses semiconductor technology; aka solid state lighting
LEED (Leadership in Energy and Environmental Design)		a building rating system developed by the US Green Building Council, includes standards for several types of buildings
Long-term power purchase agreement		contractual agreement between buyer and seller of electricity committing buyer to purchase power from seller over an extended period of time
Low Impact Hydropower Certification		standard for small-scale hydro power managed by the Low Impact Hydropower Institute
Megawatt hour (MWh)		measure of electricity produced - typical unit by which institutions are billed for electricity
Mercury		a heavy metal emitted by coal combustion that can cause short-term and chronic nervous system impairment, cancer, heart disease and other serious health damage to exposed individuals
Methane		potent greenhouse gas that is produced by decomposing biomass, landfills, and some industrial processes - methane is has twenty-one times greater global warming impact than an equivalent mass of carbon dioxide
Mountaintop removal		controversial form of mining where coal companies remove vegetation, soil, and rock layers until they reach the underground deposit, effectively removing the mountain and resulting in habitat destruction, water pollution, and reduced aesthetic beauty of natural landscapes
Natural gas		fossil fuel composed primarily of methane that can be burned to produce heat and electricity with lower conventional and greenhouse gas emissions than coal
Nuclear power		electricity produced by harnessing heat from controlled chain reactions using uranium as the primary fuel source
Nuclear waste		by-product of nuclear power, see "high-level radioactive waste"
Neurotoxin		hazardous material such as mercury that causes brain and nervous system damage when ingested
Nitrogen oxides		class of conventional air pollutants from fossil fuel combustion that contribute to smog and acid rain
Oil		liquid fossil fuel that can be burned to produce electricity
On-site generation		production of electricity from generation assets on an institution's property - typically this consists of small scale combustion turbines, wind turbines, or solar panels
Particulate matter		small particles and liquid droplets that can be inhaled and cause respiratory and heart disease
Petroleum		see "oil"
Phantom load		electricity consumed by some types of electronic equipment while in "off" mode - phantom loads can be addressed by using "power strips" with the equipment
Photovoltaic panel		technology that converts sunlight directly into electricity
PM		see "particulate matter"
Power aggregation		the aggregation of multiple institutions' electricity purchases onto one contract so that the total purchase volume is higher and better pricing can be achieved
Power Profiler		tool managed by the Environmental Protection Agency that calculates emissions from a user's electricity consumption based on zip code (which identifies the user's electric utility company)
Power strips		devices that electrical equipment can be plugged into in order to prevent electricity to be consumed by the equipment while they are in "off" mode - see "phantom loads"
Radioactive waste		see "nuclear waste" and "high-level radioactive waste"
RECs		see "renewable energy certificates"
Regulated market		electricity market with a limited number of utility companies and where customers are not able to choose their electricity provider
Renewable energy		see "green power"
Renewable energy certificates (RECs)		certificates that represent the environmental attributes of green power that may be produced within or outside of the buyer's region
Resource mix		generation assets used by an electric utility to produce power
Retail green power (bundled) products		green power products sold with conventional electricity under one contract
Reverse auction		an auction for electricity where vendors compete against competitors based on price to win a contract
Small-scale hydro		hydroelectric power produced from small dams with a generating capacity less than 20 megawatts (MW)
Smog		air pollution formed when sunlight reacts with oxides of nitrogen and hydrocarbons
SO2		see "sulfur dioxide"
Sulfur dioxide		Air pollution common with coal-fired power plants that causes acid rain
Surface mining		method of uranium mining which extracts ore from large rocks brought to the surface from underground - surface mining uses tailing ponds that can leak radioactive material into surrounding water
Tailings		by-products of coal and uranium mining that are often toxic and are stored in ponds that can pollute ground and surface water
Thermal pollution		heated water discharged from power plants into rivers and lakes
Thermal power plants		power plants that use water to 1) produce steam that turns an electrical turbine and 2) circulate through the power plant for cooling purposes
Uranium		radioactive material used in nuclear power plants
Vintage		the unique location, source, and time of a particular megawatt-hour (MWh) of electrical production
Voluntary green power purchase		the purchase of green power that is not being produced to satisfy government policies such as renewable portfolio standards
Wholesale green power purchase		purchase of green power directly from a producer (e.g., the owner of the wind turbine) rather than from a vendor (e.g., an electric utility company) that would otherwise buy the power from that producer and bundle it with other electricity supplies
Yucca Mountain		proposed long-term repository in Nevada for U.S. nuclear waste

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