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Electricity is a secondary energy source

A hand unplugging an electrical appliance from an outlet

Source: Stock photography (copyrighted)

Compact fluorescent light bulbs use about 25% of the electricity to produce the same amount of light as incandescent light bulbs.
Energy efficient light bulb.

Source: Stock photography (copyrighted)

Electricity is the flow of electrical power or charge. Electricity is both a basic part of nature and one of the most widely used forms of energy.

The electricity that we use is a secondary energy source because it is produced by converting primary sources of energy such as coal, natural gas, nuclear energy, solar energy, and wind energy into electrical power. It also referred to as an energy carrier, which means it can be converted to other forms of energy such as mechanical energy or heat. Primary energy sources are renewable or nonrenewable energy, but the electricity we use is neither renewable nor nonrenewable.

Electricity use has dramatically changed daily life

Despite its great importance in daily life, few people probably stop to think about what life would be like without electricity. Like air and water, people tend to take electricity for granted. But people use electricity to do many jobs every day—from lighting, heating, and cooling homes to powering televisions and computers.

Before electricity became widely available about 100 years ago, candles, whale oil lamps, and kerosene lamps provided light, iceboxes kept food cold, and wood-burning or coal-burning stoves provided heat.

Scientists and inventors have worked to decipher the principles of electricity since the 1600s. Some notable accomplishments were made by Benjamin Franklin, Thomas Edison, and Nikola Tesla.

Benjamin Franklin demonstrated that lightning is electricity. Thomas Edison invented the first long-lasting incandescent light bulb.

Prior to 1879, direct current (DC) electricity had been used in arc lights for outdoor lighting. In the late 1800s, Nikola Tesla pioneered the generation, transmission, and use of alternating current (AC) electricity, which reduced the cost of transmitting electricity over long distances. Tesla's inventions brought electricity into homes to power indoor lighting and into factories to power industrial machines.

Last updated: November 21, 2016

Preliminary data for the United States for 2015, except where noted.

Generation from utility-scale power plants

Total net generation 4,087,381 thousand megawatthours
Electric utility net generation 2,331,041 thousand megawatthours
Share of total net generation by energy source  
    Coal 33%
    Natural gas 33%
    Nuclear 20%
    Hydroelectric   6%
    Nonhydro renewables   7%
    Petroleum and other   1%
Number of electricity generators (2014) 19,745
Largest power plant by net generation (2014) Palo Verde (nuclear)—31,320,917 megawatthours

Generation capacity of utility-scale generators

Total electricity generating capacity (net summer)
1,068,422 megawatts
Share of capacity by energy source  
    Natural gas 47%
    Coal 27%
    Hydroelectric 10%
        Conventional   7%
        Pumped storage   2%
    Nonhydro renewables 10%
    Nuclear   9%
    Petroleum   4%
    Other <1%
Totals may not equal 100% because of independent rounding  
Largest power plant by capacity(2014) Grand Coulee Dam (hydropower)—7,079 megawatts

Consumption and price

Total electricity consumption (end use) 3,863,275 thousand megawatthours
Share of total electricity consumption by type  
Electricity retail sales (total) 96%
  Residential sector 36%
  Commercial sector 35%
  Industrial sector 25%
  Transportation sector <1%
Direct use of electricity   4%
Largest utility by retail sales (within state 2014) Florida Power & Light Company—104,431 thousand megawatthours
Retail prices by sector (average annual)  
    Residential 12.67 cents per kilowatthour (kWh)
    Commercial 10.59 cents per kilowatthour
    Industrial   6.89 cents per kilowatthour
    Transportation 10.17 cents per kilowatthour
    Average 10.42 cents per kilowatthour
State retail price rankings (average annual price for all sector) Highest—Hawaii: 26.17 cents/kWh
Lowest—Washington: 7.41 cents/kWh
Average residential monthly use (2014) 911 kilowatthours
Average residential monthly bill (2014) $110.20
Largest utility by retail sales revenues (within state in 2014) Pacific Gas & Electric Company—$12.5 billion


Emissions from power plants (2014)  
    Carbon dioxide (CO2) 2,160,342 thousand metric tons
    Sulfur dioxide (SO2) 3,485 thousand metric tons
    Nitrogen oxides NOx 2,178 thousand metric tons

Last updated: May 10, 2016