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Glossary of Green Terms

Brown Energy/Brown Power
Electricity generated from the combustion of fossil fuel, which generates significant amounts of anthropogenic greenhouse gases. Brown power sources include coal, oil and natural gas.

Climate Change
Although sometimes used synonymously with "global warming," the term implies a significant change (having important economic, environmental and social effects) in a climatic condition (such as temperature or precipitation).

Compact Fluorescent Light Bulbs
Fluorescent lamps are more efficient than incandescent light bulbs of an equivalent brightness. This is because more of the energy input is converted to usable light and less is converted to heat (allowing fluorescent lamps to run cooler). Click here for a full catalog of compact fluorescent light bulbs.

Energy Efficiency
Using less energy to accomplish the same task, such as heating or lighting a building. Using less energy lowers costs and reduces emissions.

Global Warming
An increase in the average temperature of the Earth's atmosphere, especially a sustained increase sufficient to cause climate change.

Green Building
A comprehensive process of design and construction that employs techniques to minimize adverse environmental impacts and reduce the energy consumption of a building, while contributing to the health and productivity of its occupants.

Green Energy/Green Power
Electricity generated from renewable resources, considered to be less intrusive environmentally than traditional (or "brown" power) generation. Green power sources include wind, water, landfill gas, solar and others.

Greenhouse Gas
Some gases, such as carbon dioxide, methane, and nitrous oxide, trap heat in the atmosphere by allowing sunlight to pass through while trapping the heat. Fossil fuels burned to produce electricity contribute two-thirds of these gases found in our atmosphere.

Green Tags
Two products are created when a renewable energy facility, such as a wind farm, operates. First is the electricity that is delivered to the grid. Second are the environmental benefits, emissions offsets from creating the same amount of energy from non-renewable sources. These credits, called Green Tags, Renewable Energy Credits (RECs), or Tradable Renewable Certificates (TRCs), are sold to make up the difference between what it costs to build and run a renewable energy generator and what they can sell for the power for on the open market. A purchase of Green Tags replaces fossil-fuel-fired power with clean renewable energy. Every Green Tag increases the amount of green energy in the system. For more information, visit Green-e.

Kilowatt-Hour (kWh)
The standard unit of measure for electrical energy use. One kWh is used to light a 100-watt bulb for 10 hours. Smith College pays approximately 8 cents per kWh, but this is expected to rise dramatically in the near future. Smith uses about 25,000,000 kWh per year, equivalent to 2,800 average homes in the United States.

The ratio of project cost to annual savings, usually for an energy efficiency project. If a new high-efficiency boiler costs $10,000 to install and saves $2,500 per year in fuel, the payback period is four years.

Renewable Resource
Sources of electricity, such as photovoltaic (PV) solar, wind, geothermal, and hydroelectric. Fuel sources such as ethanol, biodiesel, biomass (methane) and wood. A resource is considered renewable if it can be naturally replenished. Renewables generally have lower environmental impacts than non-renewables.

Meeting the needs of the present without compromising the ability of future generations to meet their own needs.