Today, hydropower generates power in all but two U.S. states, accounting for around 16% of global energy production. The other two states are Hawaii, which depends entirely on hydropower for its electricity; and Alaska, which contributes nearly 2% of its total energy needs from hydropower.
The world's largest producer of hydroelectric power is China, followed by Canada and Russia. The United States used to be number one, but since 1995 it has been surpassed by China. In 2010, global hydropower capacity increased by 5%, mostly due to new projects in Asia.
The International Energy Agency estimates that if current trends continue, hydropower will account for 21% of the world's electricity by 2050.
However, this estimate may be high because it does not take into account possible future increases in solar or nuclear power capacity-two technologies that have been growing rapidly over the past few years.
By comparison, current worldwide electricity consumption is about 7 billion kWh per year, with most of it (about 6 billion kWh) coming from fossil fuels: oil, natural gas, and coal. The remaining percentage is made up of small amounts of renewable energy sources such as wind and solar power.
Hydroelectricity provides power in every part of the country and is the United States' primary source of clean, renewable energy. Hydropower provides for 52% of renewable electricity generation in the United States and 7% of overall electricity generation. In 2009, hydropower units produced an estimated 21 billion kWh of electricity, which is enough to supply about 17 million homes.
The US has the world's largest collection of hydroelectric power plants with more than 1,000 facilities producing a total of approximately 2.5 million megawatts (MW) as of 2000. The National Renewable Energy Laboratory estimates that the national potential capacity is nearly 300 GW, or almost one-third of the current U.S. electric power production.
About two-thirds of all hydropower plants are located in four states: California, Oregon, Washington, and Montana. About 95 percent of all river power comes from facilities that capture the flow of single rivers. Lakes are also used for hydropower production but only 5 percent of the total is derived from this source. Rivers are the predominant resource for hydropower development because they provide large amounts of water at relatively low costs. Lakes are more expensive to build on than rivers because you need to purchase land near the lake instead of just along the river.
Hydropower accounts for over 60% of all renewable electricity generation. This sector accounts for around 16% of total power generation from all sources, including nuclear and fossil fuels. Without hydropower in the energy mix, no country has come close to reaching 100 percent renewables. Even with this significant contribution, some studies have shown that it would be possible to reach a fully renewable energy system if other renewable technologies such as solar PV were more cost-effective.
In 2017, the world production of hydropower was about 377 billion kWh, which corresponds to about 1 in 9 households in the world. It is expected that by 2050, almost all new capacity will be produced by solar photovoltaic and wind power rather than hydro.
Solar photovoltaics (PV) technology has achieved low prices due to mass production and large-scale installation. Global installed solar PV capacity reached 220 GW at the end of 2018, an increase of nearly 50% compared to the same period last year. The United States became the number one producer of solar energy, followed by China. In fact, China has installed more solar panels than any other country. The main reason is that the Chinese government supports this market with subsidies.
The world's first solar-powered car was built in 1986. Since then, many cars have been equipped with solar panels. In 2016, there were about 3 million solar-powered vehicles on the road worldwide.
North American hydroelectricity However, in the United States, hydroelectric power accounts for just a small portion of overall energy generation, with virtually all of the rest coming from coal-, gas-, or oil-fired thermal facilities or nuclear power plants. In Canada, hydroelectric power makes up about one-fifth of national electricity production.
The first large-scale use of hydroelectric power was as early as 1882, when a British company launched a project to generate electricity from the White River in Arkansas. For over a century after this initial demonstration project, development of additional hydroelectric power remained limited due to lack of interest from private industry. That changed in 2001, when two major dams were completed on the Columbia River system, which supplies most of the electricity to Washington state. Since then, several other large-scale hydro projects have been built across the United States, leading some observers to predict that hydroelectric power may eventually become the main source of electricity production in the country.
The need for increased energy production has led to the construction of many large dams over the years. Although dam construction originally was meant to provide water storage for agricultural use during times of drought and protect downstream communities from flooding, many dams now serve another purpose: electricity production. The Hoover Dam on the Colorado River is an example of a large dam constructed for irrigation purposes that is now used to produce power.