Loss of hydropower means renewable electricity is likely to decline in the 21st century

As unlikely as it might seem, renewable electricity generation is likely to decline. With cheap solar panels and wind turbines around the corner this might seem incomprehensible, but to understand why renewable electricity is in big trouble, ask yourself what the main present source of renewable electricity is. The answer to this question is hydropower. According to the IEA, 85% of renewable electricity comes from hydropower.

The IEA and some other big organization expect to see large growth in hydropower generation, but this increase appears unlikely for a number of reasons. When it comes to the impact of climate change on hydropower, the IEA’s roadmap that projects a doubling by 2050 in hydropower based itself on one study done in 2012. Looking up the study that the IEA uses, we find the following sentence:

This study has not examined the impact of increased frequency of droughts and floods, as forecast in many places with climate change. If droughts and floods become more frequent, this scenario would severely impacts hydropower production.

In other words, the argument made here that hydropower won’t be impacted by climate change is not very persuasive. Countries around the world have faced electricity rationing as a result of drought that are linked to climate change. Currently, Venezuela struggles with electricity rationing as a consequence of a severe drought.

To build new hydropower facilities faces a number of different problems. In China, 22% of water used by society is water that’s lost through evaporation from the massive reservoirs that China has built for its hydropower facilities. Nations that face a looming threat of water shortages would thus be unwise to build such massive reservoirs.

Scientific models always come with a degree of uncertainty. Whereas investment in new hydropower facilities may make sense in a stable climate, a changing climate leaves policymakers to pray that local precipitation patterns will indeed change in a fashion expected by climatologists.

Generally speaking, precipitation in our changing climate is expected to occur more commonly in the form of sudden downpours, rather than small amounts spread throughout the year. This places a big burden on hydropower facilities. When too much precipitation happens in a short periods, dams can collapse. In 1972, intense precipitation as a result of typhoon Nina led to a number of catastrophic dam failures in China. An estimated 172,000 people died as a result of these breaches.

Perhaps most important to note is the effect that climate change will have on soil erosion. Our hydroelectricity generating dams currently suffer from the effects of the decline in storage capacity of our reservoirs due to soil erosion. Dams currently lose around 1% of their storage every year.

Total global storage capacity peaked in 2006, as a result of the spread of sediment into the reservoirs, whereas storage capacity per person peaked even earlier in 1987, due to rapid population growth. As the capacity declines, so does the ability to produce electricity.

What’s most likely to happen in the coming decades is that a large share of existing hydroelectricity dams will gradually cease to function due to different factors. Some will face severe droughts and as a result prove unable to generate power. Other dams are likely to simply collapse, whether due to poor maintenance or as a result of the inevitable drastic increase in extreme weather events we will face in the years ahead.

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