Can Hydropower Survive Climate Change?

Hydropower, the largest source of clean energy, is facing an existential threat due to climate change-induced droughts.

Droughts in China, Brazil, the US, and Europe have significantly reduced hydropower generation, leading to a resurgence of coal in some regions.

Developing countries like Zambia are particularly vulnerable to hydropower shortages, hindering their ability to transition to renewable energy sources.

Hydropower is the largest source of clean energy in the world, generating more electricity than all other renewable energy resources combined.

However, the global rate of hydropower expansion is falling, and the technology faces an existential threat in many parts of the world due to changing weather patterns associated with climate change.

This could spell major trouble for global decarbonization efforts as net-zero scenarios rely on a strong continued role for hydropower with an ideal annual growth rate of around 4%.

“In the last five?years the average growth rate was less than one-third of what is required, signaling a need for significantly stronger efforts, especially to streamline permitting and ensure project sustainability,” the International Energy Agency (IEA) reports. “Hydropower plants should be recognised as a reliable backbone of the clean power systems of the future and supported accordingly.”

While hydropower remains an essential part of any net-zero scenario, historic droughts in many parts of the world have proven punishing for hydropower systems and have potentially scared off would-be investors. In 2022, major droughts in China’s Yangtze River basin reduced developed hydropower potential (DHP) by 26%, constituting a major energy security issue for the region and for China as a whole. Similar challenges have been faced in Brazil, the United States, and European countries in the Mediterranean region in recent years, among other locales scattered around the globe. Critically, these are not isolated incidents, nor are they characteristic of one particularly hot and dry period; the risk of similar extreme droughts in the future rises by nearly 90% in some climate scenarios, notably SSP585.

However, studies have shown that hydropower can remain a consistent and reliable source of energy during intense and prolonged periods of drought. During a period of drought in the United States, according to the Department of Energy, “the overall hydropower fleet sustained 80% of its average generation” and “hydropower could still be relied upon to supply flexible power during periods of high energy demand—even during the most severe droughts of the past two decades.” Moreover, hydropower could even play an integral role in drought management.

Nevertheless, during China’s severe bout of droughts in 2022, the country saw a significant return to coal, with widespread ramifications for the whole world’s decarbonization efforts. China is not alone in this pattern, either. Just this month the southern African country of Zambia approved the construction of a brand new coal burning power plant “as it battles a power crisis caused by a record drought, which has stricken its hydro-electricity generation,” according to a report by Bloomberg.

The new coal plant will be the country’s third, following quickly on the heels of Zambia’s second coal-powered plant, approved in July. Currently, Zambia relies on hydropower for 85% of its energy mix, which has rendered it extremely vulnerable to fluctuations in water supply due to extreme and changing weather patterns expected to intensify along with rising global temperatures.

Zambia’s forced embrace of the dirtiest fossil fuel is indicative of a much larger issue regarding the development of affordable and accessible renewable energy resources in developing countries. To keep with net-zero pathways, Africa and other developing nations will be required to “leapfrog” over the development of fossil fuels, essentially skipping what has been an essential step in the sequence of economic development for wealthier nations since the industrial revolution. But the case of Zambia clearly shows that such an approach is still not feasible for countries struggling to meet their country’s energy needs by any means, much less through purely renewable production capacity.

For countries that are already struggling to meet their energy security needs, any threat to capacity could result in major economic shocks. Even if hydropower is still able to produce at 80% capacity in severe drought conditions, that 20% could be make-or-break for strapped economies. This spells major trouble for hydropower and for global decarbonization plans as a whole, which need to see significant continued growth in Asia Pacific, Africa and the Middle East to balance out declining additions in other regions.