An Old Source of Renewable Energy Gets a New Look
Shiny solar panels and towering wind turbines grab headlines, but the United States’ original source of renewable energy, hydropower, could make a comeback, according to a new report.
The U.S. Department of Energy estimates that the nation could increase its hydroelectric capacity 50 percent by 2050 without building new dams.
Rather, the new capacity would come from upgrading existing hydropower facilities with more efficient technology and by constructing hydropower storage facilities that pump water uphill into reservoirs during off-peak hours, when electricity is cheap. When demand and power prices spike, the water is released downhill through turbines to generate electricity.
Such a strategy could grow hydropower capacity from 101,000 megawatts to 150,000 megawatts by 2050, according to the report.
“If this level of growth is achieved, benefits such as savings of $209 billion from avoided greenhouse gas emissions could be realized, of which $185 billion would be attributable to operation of the existing hydropower fleet,” said a Department of Energy spokesperson. “With this deployment level, more than 35 million average U.S. homes could be powered by hydropower in 2050.”
The report is a first-of-its-kind analysis by more than 300 experts to evaluate hydropower’s potential. About 2,000 of the country’s dams produce power, supplying 6 percent of electricity demand.
In 2014, wind and solar provided 7 percent of the country’s electricity—edging out hydropower for the first time.
Jim Bradley, vice president of policy and government relations at conservation group American Rivers, said increasing hydropower could be a good thing environmentally.
“Typically, to get approval to upgrade existing dams with more efficient technology means they will have to consider the environmental performance at that site as well,” Bradley said. “So if they’re going to be improving them, they’ll be improving the environmental issues as well.”
Bradley also noted that the report doesn’t signal a revival of the hydropower industry. The 50,000-megawatt expansion of hydropower is somewhat dwarfed by the Department of Energy’s plans for wind development.
“The department laid out a similar vision report for wind power in 2014 and found that it was feasible to install 340 gigawatts of new capacity in land- and offshore-based wind farms by 2050,” Bradley said. At that rate, wind power would meet 35 percent of the country’s electricity needs.
Still, hydropower could be key to ensuring that the power grid operates smoothly as more renewable but intermittent sources of energy come online.
Solar and wind power only produce energy when the sun is shining and the wind is blowing. To keep the lights on when solar and wind farms aren’t generating electricity, grid operators rely on carbon-spewing fossil fuel power plants. That’s where pumped storage comes into play: Reservoirs can act as giant batteries, storing energy generated by solar power plants and wind farms.
About 21,000 megawatts of pumped storage capacity exist, and the Department of Energy has announced $9.8 million in funding to help build more pumped storage.
There has been an increase in requests for pumped storage permits submitted to the Federal Energy Regulatory Commission in recent years, and 21 projects are under review.
A majority of the proposed projects are closed-loop systems in which the project’s water source is not a river but underground reservoirs, aquifers, or even the ocean.
Bradley says the closed-loop systems need the same environmental scrutiny that hydropower dams get.
“They’re called ‘closed-loop,’ but the water has to come from somewhere, and wherever they’re getting it can have significant environmental impacts in that region,” he said. “We think pumped storage has potential, but there are still a lot of questions about it.”