3.  We’re running out of ecosystems. According to a 2022 survey by Chinese scientists, nearly as much freshwater is lost to evaporation from reservoirs as is consumed by the world’s cities. Dams also prevent the natural flow of migratory species and sediment. In 2019, Stanford researchers concluded that building out the Mekong River’s hydropower potential would accelerate coastal erosion, risking putting the entire Mekong Delta below sea level, displacing millions of people and more than 50% of Vietnam’s rice production. Nor are dams true climate heroes—methane production in the world’s reservoirs contributes the equivalent of roughly 1 gigaton of carbon dioxide a year, or 1.3% of all greenhouse gasses produced by humanity.

1.  We don’t need rivers. Countries that have maxed out their mountain ranges can benefit from a new generation of hydropower systems that use pumped storage to augment or replace flowing rivers. These use cheap or surplus electricity from solar and wind farms to pump water uphill, then generate power from it flowing back down when needed. That reduces the need for back-up fossil fuel power stations. Governments around the world are supporting pumped hydropower research and systems, with one research firm predicting it could become a $650 billion global market within ten years.

2.  We don’t need more concrete. Thousands of US dams built for irrigation or flood control could be upgraded to generate gigawatts of electricity, according to this readable in-depth report by E360 at Yale University. E360 quotes Shannon Ames, who leads the Low Impact Hydro Institute, a nonprofit that assesses the environmental impacts of hydropower: “One, there’s potential for more hydropower at existing dams. And two, there is no need to build a new dam.”

3.  We don’t need a new grid. Floating solar panels on reservoirs could give existing dams a new lease on life, and ease powerline bottlenecks. Reservoirs are safe, engineered environments to deploy photovoltaics, which can also leverage transmission infrastructure already in place. According to scientists at the US Department of Energy, hybrid hydro-solar facilities around the world could generate over 10,000 terawatt hours of electricity every year—up to 40% of global electricity demand.

1.  AI dam designers. The complexity of choosing what type of dam to build for the most power and the least environmental harm is mind-boggling. Engineers have to juggle everything from sediment transport and flow regulation, to fish biodiversity and greenhouse gas emissions, coming together in billions of possible combinations. Cornell University researchers think that AI might be able to help. They have developed a computational model for dam design that they claim can help policymakers make the optimal decision for dam placement—with the best trade-offs giving up to four times more power than the worst. 

2.  Tracking dams from space. The worst thing that can happen to a dam for power generation, human welfare, and the environment is a catastrophic collapse, such as happened in Russia last week. But new technology can help. Researchers can now use public radar data from European satellites to track millimeter-sized changes in dams almost daily, and for years at a time. These could provide valuable early warnings of dams at risk of failure, particularly those in warzones or other disaster areas.

3.  Dams going down, dams going up. The majority of US dams are more than 50 years old, with the nation losing around 100 every year as moves to breach aging dams and restore natural river flows increase. Meanwhile, Indian scientists writing for the Global Water Forum calculated that hydropower could reliably and economically contribute nearly twice what it does today if developing countries can accelerate their adoption. The IEA estimates that Africa and Asia have harnessed only about 5% of their potential hydropower resources.