Electricity Consuming Plant

1. "Consumption of electricity" is a non-scientific expression often used to describe the conversion of electrical energy to mechanical work, heat or light.

The Joule is the unit of measurement used to quantify any type of energy. One Newton-meter of mechanical work is one Joule. One foot-pound of work is 1.36 Joules. One calorie of heat is 4.18 joules. One BTU (British thermal unit) of heat is 1054 Joules.

Most electric power plants require water to operate. Nuclear and fossil fuel power plants drink over 185 billion gallons of water per day. Geothermal power plants add another 2 billion or so gallons a day. Hydropower plants use water directly to generate power. These power plants represent the single largest consumer of water among any industrial, governmental or residential activity. Since 98 percent of the water used in power plants is returned to its source, distinctions are made between use and consumption.

Water use is a measure of the amount of water that is withdrawn from an adjacent water body (lakes, streams, rivers, estuaries, etc.), passes through various components of a power plant, and is then ultimately discharged back into the original water body. Environmental concerns surrounding water use center around any chemical or physical alteration of the water body and any impacts these changes may have on the plants, fish and animals who reside in the ecosystem.

Water consumption refers to water sucked up in power plant operations that is lost, typically through evaporation. The primary concerns surrounding water consumption is how best to utilize this essential resource, especially in areas, such as deserts in the West, where water is in short supply.

2. In 2008, about 518.5 billion kilowatt-hours (kWh) of electricity were used for cooling and ventilation by the residential and commercial sectors. Of that, about 227 billion kWh was used for cooling by the residential sector, which was about 16% of the total residential electricity consumption. About 291 billion kWh was used by the commercial sector for cooling and ventilation, which was about 22% of total commercial sector electricity consumption. Combined, that was about 17.6% of total U.S. electricity consumption in 2008.

3. Capacity is a measure of how much electricity a generator can produce under specific conditions. Generation is how much electricity a generator produces over a specific period of time. For example, a generator with 1 MegaWatt (MW) capacity that operates at that capacity consistently for one hour will produce 1 MW-hour (MWh) of electricity. If it operates at only half that capacity for one hour, it will produce 0.5 MWh of electricity. Many generators do not operate at their full capacity all the time; they may vary their output according to conditions at the power plant, fuel costs, and/or as instructed from the electric power grid operator. Net generation is the amount of gross generation less the electricity used by the generating station/power plant to operate the plant, including fuel handling, boiler and cooling water pumps, pollution control equipment, plant lighting, and computers.

4. By re-directing their electricity dollars to support environmentally benign energy resources, consumers are empowered, in states that offer supply choice, to influence the existing generating resources that are deployed to meet demand. They can also support the construction of new and cleaner electricity resources that will be built to meet overall growth in demand in the future. By supporting these power options, consumers can minimize many water use and consumption impacts. Still, it should be noted that directing one's dollars to cleaner power products in no way helps remediate damages that already have occurred. Consumers can stop the construction of new hydropower facilities or alter conditions of siting and operation, but they cannot undo previous environmental degradation that occurred at existing hydropower facilities.

5. If energy is converted or transferred at a rate of one Joule per second, the rate of energy conversion is 1 watt. The speed of energy transfer or the speed of performing work is power. If power is converted at a rate of 1 watt for 1 second, 1 watt-second or 1 Joule of energy is transferred. If energy is transferred at a rate of 1000 watts for 1 hour, 1 kilowatt-hour of energy is transferred. When it comes time to pay the electric bill, the cost of electricity consumption is the cost of the kilowatt hours of energy transferred to the user and converted to mechanical work, heat or light.