Responsible Purchasing Network

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


Creative Commons License This work by the Responsible Purchasing Network is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

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