Thermal Power Plant



In a thermal power plant, steam is produced and used to spin a turbine that operates a generator. Shown here is a diagram of a conventional thermal power plant, which uses coal, oil, or natural gas as fuel to boil water to produce the steam. The electricity generated at the plant is sent to consumers through high-voltage power lines.






Electricity is generated when a loop of conducting wire rotates in a magnetic field. In a hydroelectric plant, water falling over a dam turns turbines that spin the generators that produce electricity. The electricity flows to a transmission station where a transformer changes a large current and low voltage into a small current and high voltage. Then the electricity flows over high voltage transmission lines to a series of transmission stations where the voltage is stepped down by transformers to levels appropriate for distribution to customers. Primary lines may transmit electricity at voltages as high as 500,000 volts. Secondary lines to homes carry electricity at 240 volts or 120 volts.


The National Power Grid



High-voltage electrical transmission lines in the United States are divided into three separate grids that make up what is often called the national power grid. The three grids cover the contiguous 48 states and parts of Canada and Mexico and are known as the Western Interconnection, the Eastern Interconnection, and the Electric Reliability Council of Texas (ERCOT) Interconnection. The three grids operate independently for the most part but are connected in a few places by direct-current lines. All United States power utilities, except those in the states of Alaska and Hawaii, are connected to other power utilities through the national power grid. Dispatch centers maintain and control the flow of electricity over the grid, supplying electricity to meet the demand.


Electric Power Control Panel




An operator monitors the master control panel for an electric company in Philadelphia. The computer screens show the power line connections and routes. From such a central location, an operator can quickly identify blackouts, or large system power failures, and other power interruptions.


Northeast Blackout




Before-and-after satellite images of the Northeastern United States and parts of the Canadian provinces of Ontario and Quebec capture the worst power blackout in the history of Canada and the United States. The blackout occurred in August 2003 and affected an area covering 50 million people.



World Plugs and Outlets




Plugs and outlets enable people to use electricity in their homes, offices, and schools, and any place else where electric power is needed. Various types of plugs and outlets are used throughout the world. Some of the more popular types are shown here. Type A, also called the American type, is used in North and South America and in Japan and other parts of Asia. Type B, also called the British type, is used in the British Isles and in parts of Asia and Africa. Type C and Type SE are used in parts of Europe and Asia, as well as in limited areas in Central and South America. Type O, also called the Oceania type, is used in Australia and the countries of the South Pacific.


Ways to Conserve Electricity

Uses of Electricity

How to Conserve Electricity

Air conditioners Check and clean the air conditioner's filter once a month; make sure the air conditioning unit is the proper size for the room it is cooling; locate the air conditioner on the north or east side of a house in a shady area; ventilate the house's attic to reduce heat buildup; install ceiling fans to improve air circulation. Dishwashers Wash only a full load; turn off drying cycle, open door to air dry dishes. Clothes washers and dryers Use only with a full load; use warm or cold water, reserving hot water use only for heavily soiled clothes; use only full loads for the dryer and if a second load is necessary, dry that load immediately after the first to retain as much heat as possible; clean lint filter before each load. Computers Turn off computers when not in use or set the computer to energy-saving mode. Lights Replace incandescent bulbs with screw-in fluorescent bulbs, which use 75 percent less electricity and last at least 8 times longer; turn lights off when not needed; install light dimmers or photoelectric switches that automatically turn off lights during daylight or install timers to control use of lights; for lights used for home security, install motion detectors so lights come on only when motion is detected. New appliances Replace aging appliances with new, more energy-efficient models when possible; look for Energy Star label designating an energy-efficient appliance. Ovens and stove tops Use microwave instead of oven where possible; food in glass dishes can be cooked at lower temperature; preheating oven is usually unnecessary; on the stove top cook with covered pans and match pan size to the size of the burner. Refrigerators Check door seals to make sure there are no air leaks; clean condenser coils on the back of the refrigerator; keep refrigerator away from oven or dishwasher and give the unit breathing room; turn thermostat down to 37 degrees Fahrenheit; turn on energy saver switch. Water heaters Lower the heater setting to 120 to 130 degrees Fahrenheit; insulate the water heater and any exposed hot water pipes; use low-flow shower heads.