Hydropower produces less electricity and that slows down the energy transition

Thac Ba in Northern Vietnam. Santo Antonio in the Brazilian province of Rondonia. Masinga in Kenya. The list of major hydropower plants that had to be shut down last year due to persistent drought is long. Globally, hydroelectric power stations produced 88 terawatt hours less power last year than the year before, British energy NGO Ember reports in its annual report on global trends in electricity generation. For comparison: Belgian nuclear power stations generated 31.4 Terawatt hours last year.

The decline in power generation from hydropower has not been this great in two decades. She also fits into a trend. Until 2020, the amount of electricity from hydroelectric power plants grew every year, but in recent years this is no longer the case. Production is stagnating, despite the opening of new hydroelectric power stations. This is because the power stations are less productive as a result of droughts. Last year production was at its lowest level in five years.

“The shortage was mainly met by coal-fired power stations,” Ember notes. “That led to additional greenhouse gas emissions. The vast majority of additional electricity from coal-fired power stations was generated in countries affected by droughts.”

It has to move forward

Hydroelectric power stations in China in particular performed poorly. Because the country was hit by a persistent lack of rain in the spring, the installations produced no less than 60 percent less electricity than the year before. This meant that 59 terawatt hours of production were lost and had to be compensated by burning extra coal.

Chinese provinces such as Sichuan depend on large hydroelectric power stations along the rivers that originate in the Himalayas for much of their power supply. That electricity is also transported to other parts of China. But in 2022 and last year, only half as much electricity could be produced as normal during drought periods. Similar problems also occur in countries such as Canada, the United States and Vietnam.

The stagnation of electricity generation from hydropower is bad news. After all, strong growth in this form of sustainable electricity is required on the path to climate neutrality. According to the projections of the International Energy Agency (IEA), the amount of hydroelectric power worldwide must double to achieve energy efficiency by 2050. net zero reach. “The main sources of sustainable energy are wind and sun, but other climate-friendly sources such as nuclear power plants and hydropower are essential for a successful transition,” Ember writes.

The world now gets about as much sustainable electricity from hydropower as from sun and wind. But while the share of solar and wind increases, that of hydropower decreases. Between now and 2030, 2.9 percent more electricity must be generated from hydropower every year to make climate neutrality possible. But in 2023 there was a decrease of 2 percent. The volume produced also declined in 2021 instead of improving.

Uncertain future

Is there a structural trend caused by droughts linked to climate change? “The impact of climate change is uncertain,” Ember writes cautiously. “The effects differ geographically. But if hydropower does not grow as expected, even more wind and sun will be needed to compensate. The decline in 2023 is a step in the wrong direction.”

Hydroelectric power stations are particularly sensitive to climate change. Fluctuations in the supply of water have increased sharply in recent years. American scientists inventoried four risk factors in 2022. Glaciers are melting, causing less meltwater to reach the rivers; the warmer winters cause less snowfall and therefore less meltwater; the greater fluctuations in precipitation increase the risk of droughts; and the higher temperatures cause the water in reservoirs to evaporate more quickly.

It makes the future for hydropower more uncertain, just as many countries are investing a lot of money in new power stations. Hydropower has long been seen as a very constant and reliable source of electricity, and therefore very useful as a supplement to wind turbines and solar panels, which depend on erratic weather conditions. But the heavy investments and long depreciation periods, combined with growing production uncertainty, can make investments less attractive.

The growth of wind and solar power is going in the right direction, Ember notes. Last year, for the first time, more than 30 percent of all electricity was generated sustainably. Wind and solar accounted for 13 percent, the rest came mainly from hydropower and biomass. The bad news is that the growth of wind and solar was insufficient to fully meet the additional demand for power. Fossil sources such as coal also continued to grow. Wind and solar captured 82 percent of the demand growth, compared to 77 percent the previous year. Greenhouse gas emissions from power stations will also increase by 1 percent in 2023. Without the droughts that hampered hydropower, there would probably have been a decline of 0.4 percent.