Understanding watts, megawatts, kilowatt-hours, and more

The document defines electrical units of power (watts, kilowatts, megawatts, gigawatts) and energy (watt-hours, kilowatt-hours), providing examples of their application in household appliances, residential consumption, and power plant capacity.

• Electrical energy is measured in watt-hours, which combine the rate of electricity use (watts) and the duration of use (hours). For instance, a 15-watt bulb uses 15 watt-hours over one hour.
• Kilowatts (kW) and kilowatt-hours (kWh) are used for household and appliance measurements, where 1 kW equals 1,000 watts. A typical US home uses approximately 7,200 kWh annually, while energy-efficient refrigerators use 300-400 kWh per year.
• Larger scales of power are measured in megawatts (MW) and gigawatts (GW). One MW equals 1,000 kilowatts and is used for power plants or cities, such as a typical coal plant of 600 MW. One GW equals 1,000 megawatts; the total capacity of U.S. electricity generating plants was roughly 1,100 GW in 2012.

APA

Union of Concerned Scientists (2008). Understanding watts, megawatts, kilowatt-hours, and more. https://www.ucs.org/resources/how-electricity-measured

Chicago

Union of Concerned Scientists. Understanding watts, megawatts, kilowatt-hours, and more. 2008. https://www.ucs.org/resources/how-electricity-measured.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Understanding watts, megawatts, kilowatt-hours, and more |date=14 July 2008 |url=https://www.ucs.org/resources/how-electricity-measured |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2008understanding, author = {{Union of Concerned Scientists}}, title = {{Understanding watts, megawatts, kilowatt-hours, and more}}, institution = {Union of Concerned Scientists}, year = {2008}, month = jul, url = {https://www.ucs.org/resources/how-electricity-measured}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }