As governments look to diversify their energy mix by expanding renewable energy capacity, many are turning to solar and wind power. Meanwhile, hydropower is often overlooked by countries that do not have a tradition of hydropower production. With the ongoing conflict between the United States, Israel, and Iran, the price of fossil fuels is being pushed ever higher due to severe shortages of oil and gas. This is encouraging governments worldwide to assess their energy security and consider developing various energy sources to support greater diversification and decrease the vulnerabilities of a reliance on any one energy source. 

Hydropower has long played a major role in global energy production, with several countries around the globe relying on the power of water to provide vast amounts of clean energy. The first hydropower projects were developed in the 1800s, and hydro is now the world’s third-largest power generation source after coal and natural gas, contributing around 4,500 terawatt-hours of electricity, or 14 percent of the global total. This equates to around the same electricity production as solar and wind power combined.

China is home to around 29 percent of the world’s installed hydroelectric capacity, followed by Brazil, the United States, and Canada. However, some countries rely much more heavily on hydropower, with Norway, Paraguay, the Democratic Republic of Congo, and Albania depending on hydro for a large proportion of their electricity generation.

However, the IEA’s Executive Director, Fatih Birol, has suggested that hydropower is often overlooked, describing it as“the forgotten giant of electricity”. Birol says that it is often not included in international energy discussions, when it should be, especially with the global electricity demand set to rise at a faster pace than the overall energy demand. In 2021, the IEA published a major report on hydropower, identifying the significant potential of expanding the hydro market.

Around 60 percent of the hydro resources in emerging and developing economies are untapped. Investing in the sector could help boost energy access and power industrialisation, thereby spurring economic growth.

Unlike solar and wind power, hydropower is highly flexible, as plants are developed to rapidly adjust their generation up and down as needed, and can be stopped and restarted with relative ease. This makes them highly efficient in adapting to changes in the power demand, typically at a low cost. For this reason, hydropower could be key to clean energy diversification, filling the gap when the sun is not shining and the wind is not blowing.

Hydro resources can also be used for energy storage. Pumped-storage hydro (PSH) plants can act as giant batteries, using water instead of chemicals. At present, they are the largest form of electricity storage worldwide, with the capacity to hold 30 times more power than batteries. In addition, new technologies can make hydro plants much more efficient, meaning that investing in refurbishing and upgrading ageing plants could help boost electricity output and improve storage capacity.

There is close to 200 GW of PSH capacity worldwide, contributing around 90 percent of long-duration energy storage globally. A further 570 GW of PSH is set to be developed worldwide in the coming years. Conventional hydropower, such as the Three Gorges Dam in China, stores energy by holding water in a reservoir before releasing it to power turbines. However, PSH has the reputation as a “water battery”, as it uses excess energy, mainly from renewables, to pump water from a lower reservoir to a higher one, before allowing gravity to send the water back down pipes to boost power during low-production hours.

Despite often being overlooked, hydropower has garnered greater attention in the United States in recent months, due to President Trump’s crackdown on clean energy. A submersible hydroelectric technology is being used in the Great Lakes, one of the world’s largest freshwater bodies, which border several large North American cities, such as Chicago, Toronto, Montreal, and Detroit.

None of the five Great Lakes has substantial tides or currents to fuel hydropower, but some of the surrounding waterways do. In February, the Ocean Renewable Power Company (ORPC) announced its first urban project on the St Lawrence River in Montreal. ORPC plans to begin operating two hydroelectricity devices later this year, with 60-90 MW of resource potential in the area. The devices use carbon fibre turbines, which are turned by the flow of water. This technology has become increasingly popular in recent years, with similar projects being developed in Korea and the United Kingdom.

Despite long being used as an energy source, the potential for hydropower as part of energy diversification efforts has been greatly overlooked. As governments worldwide look for ways to strengthen their energy security and reduce reliance on volatile energy sources – such as oil and gas – hydropower could offer a major clean alternative power source, as well as provide enhanced stability through the use of hydro plants as giant batteries. 

By Felicity Bradstock for Oilprice.com

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