There are approximately 7,000 power generation plants in the United States. The largest is the Grand Coulee Dam Hydroelectric Power Facility on the Columbia River which has a maximum generation capacity of 7,100 MW (see Figure 1). However, due to the varying flow rates of the Columbia River, the plant generally produces less than 40% of its capacity over the course of a year.
The plant that generates the most electricity in the US over a full year is the Palo Verde Nuclear Power Plant which is located near Tonopah, Arizona. Palo Verde consists of three pressurized water reactors, each with a capacity of 1,240 MW, for a total capacity of 3,720 MW. Production ranges from 70-95% of capacity, with a yearly average of 3,600 MW. Palo Verde has the distinction of being the only large nuclear plant in the world that is not located near a large body of water. To cool the steam the plant uses water from treated sewage from several nearby cities.
The largest coal fired power plant in the US is the Robert W. Scherer Power Plant, located just north of Macon, Georgia, and owned by Georgia Power. The facility consists of four 880 megawatt units for a total capacity of 3,520 MW. At full capacity, the facility burns approximately 1,300 tons of coal every hour. Coal is delivered by train from the Powder River Basin, Wyoming.
The largest natural gas fired power plant in the US is the Midland Cogeneration Venture, in Midland, Michigan owned by Midland Cogeneration Venture Limited Partnership. The plant was originally designed as the Midland Nuclear Power Plant, but that project was abandoned in 1984 due to construction problems. The plant was converted to a natural gas-fired electrical and steam co-generation plant, and began operation in 1991. At that time it was the largest gas-fired steam recovery power plant in the world, with capacity of 1,560 MW and 1.35 million pounds per hour of industrial steam.
The largest geothermal plant in the US (and the world) is the Geysers, located north of San Francisco, California and operated by Calpine Corporation. The facility has 14 operating geothermal plants with a total capacity of 1517 MW and an average production factor of 63% for a yearly average of 955 MW. To maintain steam production rates, approximately 9 million gallons per day of treated sewage effluent is pumped into the reservoir. The vast amount of heat in reservoir rocks efficiently converts the water into steam and supplements the production of original reservoir steam to the Geysers power plants.
It should be noted that the largest power plant on the planet is the Itaipu Dam, located on the border of Brazil and Paraguay, with an installed capacity of 14 GW (Figure 6). In 2016 it produced 103.09 million MWh of electricity which surpassed the previous record holder, China's Three Gorges Dam, which generated 93.5 million MWh in 2016.