Humans have harnessed the power of moving water for eons. From the Greeks on up were have exploited the power of water. By 2014 hydropower is responsible for producing 17% of the world”s electrical power and about 85% of renewable energy and it continues to grow. In the next two decades 3,700 major dams may more than double the amount of total electrical capacity to 1700GW. Hydro Power is the most important and widely used renewable source of energy.
Questions to be asked are how “green”is hydro power, and how viable is it in a warming world with increasing water fluctuations and shortages? The type of facility is a consideration.
Large dams are often used for water storage, flood control, and power generation as a additional function. Some can also be used primarily for electrical generation. Small hydro can use run of the river methods and don’t store water. Pumped storage facilities don’t generate additional energy, but can store water and energy when prices are low, then release water and energy when prices are high. All having environmental impacts that differ.
Large hydro dams often means flooding of large areas, rendering the areas uninhabitable. Damming rivers blocks fish, harms animal habitat, alters river temps and dissolved oxygen levels. Clearing vegetation to build a dam can result in the result of greenhouse gases.
So although hydro power is seen as green and helping slow global warming in many areas it’s viability is affected by climate change. The hydrological cycle is being affected by the changes in weather. Precipitation patterns and increased droughts are changing water levels in rivers and behind hydro dams. Results are seen in the massive Hoover Dam…operating at 30% of capacity or a brand new dam in Nepal being rendered virtually useless by low water levels.
Hydro power will remain a big part of the energy equation, but a rethinking will be required in the face of growing uncertainty about technology, climate change, national security, and all the factors that affect energy.
Thanks to an article by David Suzuki and Ian Hanington..David Suzuki Foundation. July 14,2016.