A - F
G - L
M - R
S - Z

A - F




Adjustment or preparation of natural or human systems to a new or changing environment which moderates harm or exploits beneficial opportunities.






Any liquid biofuel suitable as a diesel fuel substitute or diesel fuel additive or extender. Biodiesel fuels are typically made from oils such as soybeans, rapeseed, or sunflowers, or from animal tallow. Biodiesel can also be made from hydrocarbons derived from agricultural products such as rice hulls.




The zone at and adjacent to the earth’s surface where all life exists; all living organisms of the earth.


The standard measure of heat energy. It takes one Btu to raise the temperature of one pound of water by one degree Fahrenheit at sea level. For example, it takes about 2,000 Btu to make a pot of coffee. One Btu is equivalent to 252 calories, 778 foot-pounds, 1055 joules, and 0.293 watt-hours. Note: In the abbreviation, only the B is capitalized.


A family of artificially produced chemicals receiving much attention for their role in stratospheric ozone depletion. On a per molecule basis, these chemicals are several thousand times more effective as greenhouse gases than carbon dioxide. Since they were introduced in the mid-1930s, CFCs have been used as refrigerants, solvents and in the production of foam material. The 1987 Montreal protocol on CFCs seeks to reduce their production by one-half by the year 1998.




The range of temperatures over which the majority of persons feel comfortable (neither too hot nor too cold).




The study of interrelationships of animals and plants to one another and to their environment.




A property of the basic particles of matter. A form of energy having magnetic, radiant and chemical effects. Electric current is created by a flow of charged particles (electrons).


The capacity for doing work. Forms of energy include: thermal, mechanical, electrical and chemical. Energy may be transformed from one form into another.


Using less energy to provide the same service.


A control system (often computerized) designed to regulate the energy consumption of a building by controlling the operation of energy consuming systems, such as the heating, ventilation and air conditioning (HVAC), lighting and water heating systems.

ESCO – Efficiency Service Company

A company that offers to reduce a client’s electricity consumption with the cost savings being split with the client.


Oil, coal, natural gas or their by-products. Fuel that was formed in the earth in prehistoric times from remains of living-cell organisms.


A substance that can be used to produce heat.


Synthetic gas used for heating or cooling. It has less energy content than pipeline-quality gas.

G - L


The process where biomass fuel is reacted with sub- stoichiometric quantities of air and oxygen usually under high pressure and temperature along with moisture to produce gas which contains hydrogen, methane, carbon monoxide, nitrogen, water and carbon dioxide. The gas can be burned directly in a boiler, or scrubbed and combusted in an engine-generator to produce electricity. The three types of gasification technologies available for biomass fuels are the fixed bed updraft, fixed bed downdraft and fluidized bed gasifiers. Gasification is also the production of synthetic gas from coal.


Natural heat from within the earth, captured for production of electric power, space heating or industrial steam.


A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.[1] The primary greenhouse gases in the Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth’s surface would average about 33°C colder than the present average of 14 °C (57 °F).


The presence of trace atmospheric gases make the earth warmer than would direct sunlight alone. These gases (carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], tropospheric ozone [O3], and water vapor [H2O]) allow visible light and ultraviolet light (shortwave radiation) to pass through the atmosphere and heat the earth’s surface. This heat is re-radiated from the earth in form of infrared energy (longwave radiation). The greenhouse gases absorb part of that energy before it escapes into space. This process of trapping the longwave radiation is known as the greenhouse effect. Scientists estimate that without the greenhouse effect, the earth’s surface would be roughly 54 degrees Fahrenheit colder than it is today – too cold to support life as we know it.


The total market value of the goods and services produced by a nation before deduction or depreciation charges and other allowance for capital consumption and is widely used as a measure of economic activity.






Electricity produced by falling water that turns a turbine generator.








The most commonly-used unit of measure telling the amount of electricity consumed over time. It means one kilowatt of electricity supplied for one hour. In 1989, a typical California household consumes 534 kWh in an average month.


Gas generated by the natural degrading and decomposition of municipal solid waste by anaerobic microorganisms in sanitary landfills. The gases produced, carbon dioxide and methane, can be collected by a series of low-level pressure wells and can be processed into a medium Btu gas that can be burned to generate steam or electricity.


Amount of money necessary to own, operate and maintain a building over its useful life.


Gases transformed into liquid form. These include butane, butylene, ethane, ethylene, propane and propylene.


A mixture of gaseous hydrocarbons, mainly propane and butane that change into liquid form under moderate pressure. LPG or propane is commonly used as a fuel for rural homes for space and water heating, as a fuel for barbecues and recreational vehicles, and as a transportation fuel. It is normally created as a by-product of petroleum refining and from natural gas production.

M - R


The sum that has to be paid the next increment of product of service. The marginal cost of electricity is the price to be paid for kilowatt-hours above and beyond those supplied by presently available generating capacity.

METHANOL (also known as Methyl Alcohol, Wood Alcohol, CH3OH)

A liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood.


A light hydrocarbon that is the main component of natural gas and marsh gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gases. Chemical formula is CH4.


Megawatt. The standard unit of measure for the amount of power produced from a plant. One megawatt is 1,000 kilowatts.


Hydrocarbon gas found in the earth, composed of methane, ethane, butane, propane and other gases.


Vehicles that are powered by compressed or liquefied natural gas.


Power obtained by splitting heavy atoms (fission) or joining light atoms (fusion). A nuclear energy plant uses a controlled atomic chain reaction to produce heat. The heat is used to make steam run conventional turbine generators.


A rating scale used to grade gasoline as to its antiknock properties. Also any of several isometric liquid paraffin hydrocarbons, C8H18. Normal octane is a colorless liquid found in petroleum boiling at 124.6 degrees Celsius.


Acronym for Organization of Petroleum Exporting Countries founded in 1960 for unify and coordinate petroleum polices of the members. Headquarters is in Vienna, Austria.


A kind of oxygen that has three atoms per molecule instead of the usual two. Ozone is a poisonous gas, but the ozone layer in the upper atmosphere shields life on earth from deadly ultraviolet radiation from space. The molecule contains three oxygen atoms (O3).


Unburned fuel particles that form smoke or soot and stick to lung tissue when inhaled. A chief component of exhaust emissions from heavy-duty diesel engines.


Use of the sun to help meet a building’s energy needs by means of architectural design (such as arrangement of windows) and materials (such as floors that store heat, or other thermal mass).




A semiconductor that converts light directly into electricity.




Electricity for use as energy.


A central station generating facility that produces energy.


A gas that is both present in natural gas and refined from crude oil. It is used for heating, lighting and industrial applications. See also LPG.


A unit of thermal resistance used for comparing insulating values of different material. It is basically a measure of the effectiveness of insulation in stopping heat flow. The higher the R-value number, a material, the greater its insulating properties and the slower the heat flow through it. The specific value needed to insulate a home depends on climate, type of heating system and other factors.


The flow of energy across open space via electromagnetic waves such as light. Passage of heat from one object to another without warming the air space in between.


Coal, natural gas, wood or other fuel that is used in the form in which it is found in nature, without chemical processing.


A facility that separates crude oil into varied oil products. The refinery uses progressive temperature changes to separate by vaporizing the chemical components of crude oil with different boiling points. These are distilled into usable products such as gasoline, fuel oil, lubricants and kerosene.


The fuel component of municipal solid waste (MSW), which is the by-product of shredding MSW to a uniform size, screening out oversized materials and isolating ferrous material in magnetic separation. The resulting RDF can be burned as a fuel source.


Resources that constantly renew themselves or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat russian mail bride in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or less-developed sources such as tidal power, sea currents and ocean thermal gradients.


Broad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles. (Same as “aftermarket”.).

S - Z


An energy carrier which has been produced from primary energy in a conversion process (e.g. electricity, hydrogen, petrol).


Originally “smog” meant a mixture of smoke and fog. The definition has expanded to mean air that has restricted visibility due to pollution. Pollution formed in the presence of sunlight is called photochemical smog. According to the U.S. EPA, smog is “a mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air involving smog-forming chemicals. A major portion of smog-formers come from burning of petroleum-based fuels such as gasoline. Other smog-formers, volatile organic compounds, are found in products such as paints and solvents. Smog can harm health, damage the environment and cause poor visibility. Major smog occurrences are often linked to heavy motor vehicle traffic, sunshine, high temperatures and calm winds or temperature inversion (weather condition in which warm air is trapped close to the ground instead of rising). Smog is often worse away from the source of the smog-forming chemicals, since the chemical reactions that result in smog occur in the sky while the reacting chemicals are being blown away from their sources by winds.”


A photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon.


A component of an active or passive solar system that absorbs solar radiation to heat a transfer medium which, in turn, supplies heat energy to the space or water heating system.


Heat and light radiated from the sun. Solar radiation reaching the earth and its use for the production of electricity and heat.


Solar heating or hot water systems provide two basic functions: (a) capturing the sun’s radiant energy, converting it into heat energy, and storing this heat in insulated storage tank(s); and (b) delivering the stored energy as needed to either the domestic hot water or heating system. These components are called the collection and delivery subsystems.


Sustainable development refers to a mode of human development in which resource use aims to meet human needs while ensuring the sustainability of natural systems and the environment, so that these needs can be met not only in the present, but also for generations to come. The term ‘sustainable development’ was used by the Brundtland Commission, which coined what has become the most often-quoted definition of sustainable development: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”






1. Law of Conservation of Energy – energy may be transformed in an isolated system, but its total is constant




A measure of how well heat is transferred by the entire window – the frame, sash and glass – either into or out of the building. U-value is the opposite of R-value. The lower the U-factor number, the better the window will keep heat inside a home on a cold day.