Droughts Lead to Drop in Hydro Generation in 2023

A new analysis of government data by Reuters has found that India’s hydroelectricity generation fell at the steepest pace in nearly four decades during the year ended March 31, citing how “erratic rainfall forced further dependence on coal-fired power amid higher demand.” The country saw a drop in hydropower generation of 16.3 percent in that time frame.

India’s story speaks to a wider trend: Last year, there was a year-on-year drop of an estimated 99.74 terawatt hours in hydropower generation worldwide, according to monthly data published by Ember, a UK-based energy think tank. This decline was driven mostly by a drop in hydropower output from China, which is by far the world’s biggest hydropower producing country, and had similarly experienced droughts and long-lasting heat waves that affected reservoir levels. According to Ember analysis of data running through to July 2023, the deficit of hydropower led to a small increase in fossil fuels.

The issue with hydropower targets not being met is that other energy sources are needed to fill in the gap in order to meet energy needs. Ember researchers explain in their 2023 mid-year electricity report: “When hydro generation remains below expectations, it leaves a deficit that new low-carbon electricity (mostly wind and solar) has to make up for in addition to meeting additional electricity demand and replacing fossil fuels. Only when sources like wind and solar grow fast enough to overcome both the uncertainty of output from other clean sources as well as growing electricity demand will we see substantial reductions in fossil generation and emissions.”

At least in India, hydropower is tricky in this regard, according to one meteorological expert cited in the Reuters report, who said that erratic rainfall means India should not consider hydro a reliable power source in the future.

Ember analysts are in agreement that there is a question surrounding reliability of hydropower and stress that predicting a global outlook on the energy source’s production is difficult for a number of reasons, including the fact that while many countries are experiencing lower output than at the start of the century, historical-long trends remain “ambiguous”.

At the same time, different regions around the world are likely to be affected to varying degrees by changing weather patterns exacerbated by climate change. “Changes in rainfall patterns and intensity as well as increased evaporation will affect hydro output both positively and negatively depending on the region”, Ember analysts write. “While central Africa, India, central Asia and northern high latitudes are expected to have higher hydropower potential, southern Europe, the southern U.S. and others could see their hydro potential worsen.” Regional differences will exist within countries themselves too.

In order for the world to be on track for net zero emissions by 2050, hydro generation would have to rise by 4 percent annually from 2021 to 2030, according to Ember. But as the following chart shows, this has not been the case so far.

This chart is based on Ember’s yearly electricity data between 2010-2022, which covers electricity generation from over 200 geographies. The 2023 estimate was calculated from Ember’s monthly electricity data, which covers electricity generation from 85 geographies.