- We have put together this glossary of commonly used terms when describing wind and solar power, and other terms you may have heard when refering to renewable energy.
Alternating Current(AC): electricity delivered by utilities at 60 Hz, and 120 volts.
Amp: electrical current; a measure of flowing electrons.
Amp-hour: measure of flowing electron for a period of time.
Battery: A collection of cells that store electrical energy; each cell converts chemical energy into electricity or vice versa, and is interconnected with other cells to form a battery for storing useful quantities of electricity.
BTU: British Thermal Unit, the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit; 3411 BTUs equals one kilowatt-hour.
Compact Fluorescent Light (CFL): a modern light bulb with integral ballast using a fraction of the electricity used by a regular incandescent light bulb.
Direct Current (DC): the complement of AC, or alternating current, presents one unvarying voltage to a load. This is standard in automobiles.
Energy-efficient: Electrical lighting devices which produce the same amount of light (lumens) using less electrical energy than incandescent electric light bulbs. Such devices are usually of the fluorescent type, which produce little heat, and may have reflectors to concentrate or direct the light output.
Energy sources: Energy sources are: 1. fossil fuels (coal, oil, gas); 2. nuclear (fission and fusion); 3. renewables (solar, wind, geothermal, biomass, hydro).
Generator: any device that produces electricity.
Geothermal Energy: Geothermal energy is the natural heat of the earth stored deep below the earth’s surface. It can be in the form of steam, hot liquid or hot dry rock. Wells drilled deep into the ground bring steam and hot water to the surface. The steam, or steam produced by the fluids in a heat exchange process, is used to drive a turbine generator to make electricity. Modern technology allows spent geothermal fluids and non-condensable gases to be reinjected back into the ground, eliminating surface disposal and air pollution.
Gigawatt: One-billion watts. (See “watt”)
Global warming: The gradual warming of the earth due to the "greenhouse effect."
Greenhouse effect: The trapping of the sun's radiant energy, so that it cannot be reradiated. In cars and buildings the radiant energy is trapped by glass: in the earth's atmosphere the radiant energy is trapped by gasses such as chlorofluorocarbons (CFCs) and carbon dioxide.
Grid: A utility term for the network of wires that distribute electricity from a variety of sources across a large area. The "grid" powers most homes and offices across the country.
Heat Exchanger: Device that passes heat from one substance to another; in a solar hot water heater, for example, the heat exchanger takes heat harvested by a fluid circulating through the solar panel and transfers it to domestic hot water.
Hybrid System: For a solarized heat engine, a hybrid engine is one that has been designed to operate with solar power or another heat source, such as natural gas. In principle, a hybrid system could provide power 24 hours per day, using solar energy when the sun is available and another energy source the rest of the time.
Hydro Power: Power obtained from the natural movement of masses of water.
Internal Combustion: Term used to describe heat engines in which the working fluid of the engine is mixed with and comes into direct contact with the heat source and then exhausted after the expansion process.
Inverter: The electrical device that changes direct current (DC) into alternating current (AC).
Kilowatt: 1000 watts.
Kilowatt/hour: One kilowatt of power used for one hour. A typical house uses 750 kW/hrs per month.
Kyoto Protocol: It commits industrialized countries to firm reductions in greenhouse gas emissions. The United States is to reduce emissions by 7% below 1990 levels by the years 2008-2010. TheU.S. signed the Protocol in November 1998, but it has not been submitted by the Administration to Congress for ratification due to Congressional concerns about the lack of requirements for emission reductions by developing nations.
Load: An electrical device, or the amount of power required by such a device.
Megawatt(MW): 1,000,000 watts.
Modules: The manufactured panels of photovoltaic cells; a module typically houses thirty-six cells in an aluminum frame covered with a glass or acrylic cover and provides a junction box for connection between itself, other modules in the array, and the solar electric system.
Net metering: A desirable form of buy-back agreement in which the line-tied house's electric meter turns in the utility's favor when grid power is being drawn, and in the system owner's favor when the house generation exceeds its needs and electricity is flowing into the grid. At the end of the payment period, when the meter is read, the system owner pays the utility the difference between what was used and what was produced.
"Off-the-grid": Not connected to the power lines: electric self-sufficiency.
Photovoltaics(PVs): A technology for using semiconductors to directly convert light into electricity.
Renewable Energy: An energy source that renews itself without, effort; fossil fuels, once consumed, are gone forever, while solar energy is renewable in that the sun we harvest today has no effect on the sun we can harvest tomorrow.
Solar Cell: Device made of semiconductor materials that produces a voltage when exposed to light.
Solar Cooling: The use of devices that absorb sunlight to operate systems similar to gas-fired refrigerators.
Solar Electricity: Electricity produced directly by action of sunlight; photovoltaics
Solar Greenhouse: A conventional greenhouse in which mass is added for heat storage, double glazing is used, and the north side is attached to a house or bam.
Solar Heating: Processes, active or passive, that derive and control heat directly from the sun.
Standard Offer Contract: An Ontario initiative that pays power producers 11¢ kw/hr for wind plus 42¢ for solar power. This is a 20 year contract.
Stand-Alone System: A PV installation not connected to a utility power line. A 'direct system' uses the PV-produced electricity as it is produced, e.g., a solar-powered water-pumping station. A 'battery storage system' stores the PV-produced electricity for use a later time, e.g. at night or on cloudy days.
Sustainable: Material or energy sources that, if managed carefully, will provide at current levels indefinitely.
VAWT: Virtical Access Wind Turbine.
Volt: Measure of electrical potential, 110-volt house electricity has more potential to do work than an equal flow of 12-volt electricity.
Watt: Measure of power (or work) equivalent to 1/746 of a horsepower.
Wind power: Harnessing the wind with turbines to produce mechanical power or electricity. The wind turns the blades of a windmill-like machine. The rotating blades turn the shaft to which they are attached. The turning shaft typically can either power a pump or turn a generator, which produces electricity. For producing large amounts of electricity, many machines can be grouped together to form a “wind farm.”
Wind turbine: Device powered by wind which produces mechanical energy. This mechanical energy can be converted into electricity.