Page 307 - Managing Global Warming

Hydropower 267

World electricity generation by fuel type in 2016
(Total 24,674 TWh)

Nuclear; 9.8%
Natural gas; 22.1%

Hydropower; 16.6%
Oil; 4.8%
Renewables; 24.4%

Coal; 39.0%
Wind+ solar; 5.7%

Other renewables 2.1%

Fig. 8.1 Share of renewables in the global electricity system 2016 [2–4].

which was commissioned on September 30, 1882 on Fox River at the Vulcan Street
Plant, Appleton, Wisconsin, United States, lighting two paper mills and a residence
[1]. Early hydropower plants were much more reliable and efficient than the fossil-
fuel-fired power plants, resulting in a proliferation of small- to medium-sized hydro-
power stations distributed wherever there was an adequate supply of water and a need
for electricity. By 1886, there were 45 hydroelectric power plants in operation in
United States. Many other countries followed suit, such as Norway, where the first
hydropower plant began operation in 1885 in the town Skien. Only a few years later,
in 1890, the town of Hammerfest, north of the Arctic circle in Norway, had electric
street lights supplied from a municipal hydropower system. By the end of the century,
14 towns in Norway had electricity supplied from hydropower [5].

8.2 Hydropower generation—Theory

Hydropower is “fueled” by water moving in the hydrological cycle (water cycle). The
water cycle is powered by solar energy: Solar radiation reaching the surface of the
earth is converted into heat, which, in turn, evaporates water. Nearly 50% of all solar
energy input to the earth is used for evaporation and converted into latent energy in the
form of water vapor. Some of the water vapor (22%) in brought in over land areas
where it later condenses into clouds and precipitation. Some of the precipitation fall-
ing on land surfaces generates runoff and flows back toward the sea, under the influ-
ence of gravity. Since the water cycle is powered by solar energy, it will continue as
long as the sun shines, and makes hydropower a renewable and energy sustainable
resource.