Preface. Hydropower comprises 71% of renewable energy worldwide. Nations like the U.S. and Europe have dams that have reached the end of their lifespan, so more are being torn down than built. In the U.S. 546 dams were removed between 2006 and 2014.
This contains excerpts and paraphrasing of three news stories
- 11 Jan 2019 the costs of environmental damage and dam removal need to be added into calculations for whether to build a dam or not
- 19 November 2014 NewScientist article by Peter Hadfield “River of the dammed“,about the Chinese Three Gorges project
- 2012: the greenhouse gas emissions of hydropower
Moran, E. F. et al. 2018. Sustainable hydropower in the 21st century, Proceedings of the National Academy of Sciences.
Before developing countries build more dams, they need to take the following into account when estimating the cost
- Loss of biodiversity, especially fish species
- Social consequences, such as the displacement of thousands of people and the financial harm done
- That climate change, especially drought, and evaporation from higher temperatures, which will lead to less water stored for agriculture and electricity
- The cost of removing a dam is extremely high, so high dams wouldn’t be built if this cost were included. Many new dams in Brazil and other nations will have a short lifespan — just 30 to 50 years
Hadfield, P. 2014. “River of the dammed“. NewScientist.
Dams typically last 60 to 100 years, but whether Three Gorges can last this long is questionable given the unexpectedly high amounts of silt building up. Since fossil fuels are finite, as is uranium, to keep the electric grid up many see building more dams for hydropower as absolutely essential. Hydropower is also one of the few energy resources that can balance variable wind and solar as well.
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