For a century, hydropower has been synonymous with gigantic dams, engineering feats that provide renewable energy but displace communities and destroy ecosystems.
New research published this week by Global Energy Monitor reveals that hydroelectric projects are transforming: with the same gravitational qualities of water, but generally without building large traditional dams such as the Hoover dam in the American West or the Three Gorges dam in China.
New research published on Tuesday, May 2, 2023, by Global Energy Monitor reveals an ongoing transformation in hydroelectric projects – using the same gravitational qualities of water, but normally without building large traditional dams such as the Hoover in the American West or Three Gorges in China. Instead, a technology called pumped accumulation is expanding rapidly.
Instead, a technology called pumped storage is expanding rapidly.
These systems require two reservoirs: one at the top of a hill and one at the bottom.
When the electricity generated by nearby power plants exceeds demand, it is used to pump water uphill and essentially fill the upper reservoir like a battery.
Later, when the demand for electricity increases, the water is released into the lower reservoir through a turbine and generates power.
Pumped storage is not a new idea.
But it's having a renaissance in countries where wind and solar are also growing, helping to calm concerns about climate-related declines in renewable energy production.
"Our data shows that pumped storage is going to grow much faster than conventional dams," said Joe Bernardi, director of Global Hydropower Tracker at Global Energy Monitor.
"This trend is most pronounced in China, which accounts for more than 80 percent of planned projects worldwide."
Some of the largest systems produce enough energy to power two million American homes for one hour.
In recent years, China has accounted for about half of the world's growth in renewables.
According to official documents, every year between now and 2030, China will deploy more wind and solar capacity than Germany currently has.
As renewables increasingly contribute to China's power grid, the country is looking for mechanisms to ensure that fluctuations in wind and solar production do not slow down grid supply.
Part of that guarantee comes from the continued growth of fossil fuels, especially coal, which China has in abundance.
China's pumped storage strategy will not directly equate to a reduction in coal use.
China has stopped financing coal projects abroad, but in the country last year it approved the construction of more coal plants than ever before.
And it is already by far the world's largest consumer of coal, a particularly dirty fuel.
However, even as China doubles its coal consumption, it is reducing the total proportion of energy it gets from coal.
Right now, China is the world leader in wind, solar and hydroelectric capacity.
"For China, pumped accumulation is the winning horse that provides flexible support for wind and solar production. It's cheaper than the other battery options and can store more energy," said Liu Hongqiao, an independent energy sector consultant specializing in renewable energy in China.
According to Liu, pumped storage has also been crucial in justifying renewables in China, as the national power grid is not prepared to absorb 100 percent of the wind and solar power being produced. Some of it will have to be stored to prevent it from going to waste, he said.
"In China, coal is not going anywhere anytime soon," said Cosimo Ries, an analyst at research firm Trivium China.
"But in the coming decades it will gradually become aflexible and smaller source of energy compared to pumped-action hydro."
Data from Global Energy Monitor shows that another type of hydropower technology is prevalent, particularly in mountainous places like Nepal.
So-called run-of-the-river hydroelectric power stations are in rivers, but they don't create giant reservoirs behind them.
Without the reservoir, power generation depends on seasonal water flows, but it is less damaging to the environment and less prone to catastrophic failures in tectonically active areas such as the Himalayas.
Around the world, hundreds of run-of-the-river hydropower plants have been built or are under construction, although they tend to produce less energy.
Environmental disturbance is not the only reason conventional dams are becoming less prevalent.
They are also bad at saving water, as their reservoirs offer large surfaces for evaporation.
And when they settle in rivers that cross international borders, they can often lead to disputes over water.
Many rivers simply already have too many dams.
Hydroelectric reservoirs can also release a considerable amount of methane, a potent greenhouse gas, which comes from microbes that thrive in these environments and from the decomposition of vegetation in flooded areas.
According to Bridget Deemer, an ecologist with the U.S. Geological Survey, reservoirs could be the source of three to seven percent of human-caused methane emissions.
c.2023 The New York Times Company
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