Dany Tome spent five weeks at the National Renewable Energy Laboratory’s (NREL) campus in Golden, Colo., in a partnership between Norway and the U.S. Funded by the U.S. Department of Energy’s Water Power Technologies Office, the knowledge exchange program supports collaboration across national laboratories, universities and oceans to advance hydropower.
Hydropower is the biggest source of renewable energy worldwide, generating more electricity than all other renewables combined, according to the International Energy Agency. And pumped storage hydropower accounts for 94% of global energy storage. But as countries add more affordable, efficient solar and wind energy technologies to their power grids, what is hydropower’s role in this renewable future?
Norway gets 98% of its energy from renewable resources, and most of that (92%) is from hydropower. Although the U.S. only gets about 6% of its electricity from hydropower, both countries have significant potential to get more electricity — or other benefits — from hydro. Some hydropower plants, for example, can generate energy on demand, meaning hydropower can fill gaps when the sun sets or wind slows to ensure the grid remains reliable and resilient.
Both countries rely on similar types of hydropower: primarily large, reservoir-based plants. To fill those reservoirs, hydropower plants depend on snow cap or glacier melt and rainwater — which could shrink as the world heats up. The two countries — and the world — share something else, too: climate change.
“These things are not tied to countries. Worldwide, it’s a similar effect,” said Mayank Panwar, referring to climate change impacts. Panwar, a senior research engineer at NREL, hosted Tome and several other hydropower researchers from the University of South-Eastern Norway in the summer of 2023.
Although wind and solar will likely overtake the giant in years to come, hydropower will continue to play a key role backing up clean energy power grids worldwide. Many countries are exploring how modern versions of this renewable heavyweight might integrate into future clean energy grids.
Hydropower technologies are not without flaws: For example, facilities can, depending on where and how they are built, affect fish migration. Today’s hydropower technologies are more environmentally friendly than their predecessors. And both Norway and the U.S. are studying how to mitigate hydropower’s environmental, ecosystem and community impacts through, for example, safe fish passage technologies.
Existing hydropower facilities could become more efficient with modern upgrades, repairs and digital improvements. If the two countries can digitize their analog plants, operators could better control how much energy they generate (and when) and adapt to changing grid needs.
But many of these new hydropower technologies are still being developed. Before countries invest in what could be expensive, time-consuming upgrades to facilities, they need to know which come with the greatest benefits and how these changes could impact a future clean energy grid.
Panwar and Tome, along with their NREL and Norway colleagues, hope to answer these big questions. Panwar, for example, recently built a platform that can emulate new hydropower technologies and simulate how they might function once connected to a power grid. While Panwar explores broad, grid-wide questions, Tome is focused on the most nitty-gritty, fundamental part of a hydropower plant: the generator.
Tome fell in love with machines during one of his undergraduate degrees. (He has one in physics and another in electrical engineering.) In his home country of Honduras, Tome remembers a professor saying to him in the lab, “Let’s build a six-phase machine.” He might as well have said, “Let’s build a unicorn.” Electrical systems, like generators and power grids, typically only have three phases (phases indicate how much power the system delivers at a time). Tome did not think it was possible to add more. Now, he cannot get the unicorn out of his head.
Tome earned double master’s degrees in wind energy and electrical engineering from the Norwegian University of Science and Technology and Delft University of Technology, respectively. In his graduate work, he designed a 13-phase generator for wind turbines, which could increase the amount of electricity a turbine could generate. But after his master’s, Tome switched to hydropower. “In Honduras, we have a lot of hydropower resources,” he said. “And I was like, ‘OK, this may be suitable. I can help my country with this.’”
While at NREL, Tome found a potential solution. Working with Panwar, he studied how hot hydropower generators can get before they reach destructive temperatures. He discovered the traditional thermal threshold — the temperature when hydropower plants would shut down — may be far higher than originally thought. That threshold could be even higher if generators are better-insulated and kept cooler for longer.
That finding could help the U.S. and Norway ramp up clean energy production — without building new plants. If existing hydropower plants can run generators for longer, both countries could produce more clean energy with their existing fleets.
“In some ways, it actually opens Pandora’s box, because now we need to think differently about how to operate these machines and how they are going to affect the grid,” Tome said.
Tome plans to return to NREL to continue working with Panwar. The duo plan to simulate how hot their hot new engines could get and whether these generator-level changes might impact the grid.
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy LLC.
