Harnessing the power of moving water to generate electricity is known as hydroelectricity. In order to generate electricity from the kinetic energy in moving water, the water has to move with sufficient speed and volume to spin a turbine, which in turn rotates a generator that produces the electricity. The volume of the water is increased using dams; while its high flow speed comes from the fact that it’s released at a steep gradient through an opening in the dam.
Hydroelectricity is a renewable resource and does not emit pollution or greenhouse gases. Nonetheless, it can still have harmful environmental and social consequences. Blocking rivers with dams can degrade water quality, damage habitats, block the passage of migratory fish, and displace local communities. So, there are definitely drawbacks with hydroelectricity; although – if set up correctly – it can be a sustainable source of electricity that helps to end our reliance on fossil fuels and reduce the imminent threats of climate change.
In 2015, hydropower accounted for 16.6% of the world’s total electricity. Here are the top 6 producers of hydropower.
By an extremely large margin, China is the largest producer of hydroelectricity, totalling 1,180 terawatt hours of energy in 2016. This is more than the combined hydroelectricity production of Brazil, Canada, and the US. China also has the world’s largest hydroelectric power station, the Three Gorges Dam, located on the Yangtze River.
Hydropower provides more than 70% of Brazil’s electricity. The country currently has 158 hydroelectric power stations, with 9 additional plants under construction, and other 26 that have been authorised. The Itaipu Dam, located on the Parana on the Brazil-Paraguay border, is the world’s second biggest hydroelectric power plant.
The 11-GW Belo Monte plant, when it is finished being built, will be the third largest hydroelectric power plant in the world. However, the construction of this dam has sparked many environmental concerns, as well as repeated resistance from indigenous groups.
Canada generates 60% of its electricity with hydropower, with this renewable source of energy expected to increase up to 295% by 2050. Despite these impressive achievements and projections, a report from the University of British Columbia underscores that hydropower is no longer the greenest, cleanest option. Experts say that other renewables, such as wind and solar, are preferable. Indeed, hydropower has had detrimental impacts on indigenous, lands, territories, and resources in the country.
Trump has said he wishes the US would turn to hydropower as a source of energy, even though it already has. Hydropower plants generated about 6.5% of the electricity used in the country in 2016. So it isn’t clear if Trump is calling for more investment into hydropower or if he was just unaware of how much hydroelectric power the country actually utilises.
Most of the country’s hydropower comes from facilities that have been around for many years (the average plant has been in operation for 64 years). US hydropower is expected to grow from 101 gigawatts (GW) of combined generating and storage capacity in 2015 to nearly 150 GW by 2050.
Hydropower accounts for around 17% of Russia’s total power generation mix and around 99% of the total electricity generated from renewable sources. Russia has also been building mini-hydropower plants in order to supply remote regions of the country with hydroelectricity, without damaging the environment. The country is second in the world in terms of hydro potential, yet only 20% of this potential has been developed
Although Norway isn’t technically the biggest producer of hydropower in the world, 99% of all its electricity comes from hydropower. This is partly thanks to Norway’s low energy demands (only 5 million people live in the country). Norway is aiming for 67.5% renewable energy by 2020, with research suggesting that the Nordic country’s energy supply can be sustainable by 2030.
About the author: Sam Woolfe @samwoolfe
Sam is a writer who is especially interested in space exploration, sustainability, tech, agriculture, and nutrition.