Small hydro is like big hydropower, but without the environmental side-effects that come from damming rivers. Across the U.S., there are thousands of places where sites could generate clean, predictable, and affordable small-scale hydropower, often with benefits to local communities.
The sites are mostly existing dams that haven’t been converted for power generation, or old hydro plants that have ceased production. A Department of Energy report says converting just 100 of them could produce eight gigawatts of capacity–about half the U.S.’s current solar base.
Colorado-based Gravity Renewables is making a start. It’s bought 12 dam sites so far and started generating power at five of them. The most recent is a joint project with Skidmore College, in upstate New York. Gravity is updating a hydro facility at Chittenden Falls, which should allow the college to meet 18% of its electricity needs.
Chittenden started life as a mechanical mill in 1810, before becoming first producing electricity in the 1980s. Dozens of such sites were converted following the 1978 Public Utility Regulatory Policies Act, which for the first time enabled independent producers to sell power to the grid. Chittenden was developed by a local entrepreneur who died in 2005.
“We’re taking advantage of this forgotten legacy of the Industrial Revolution,” says Ted Rose, CEO of Gravity Renewables. “There are these textile mills and paper mills all over the Northeast, Midwest, and Southeast. I think of them as the original distributed energy sites.”
The arrangement with Skidmore is based on “remote net metering” which credits producers even for power not generated on their property. Gravity owns the site, though Skidmore plans to build a classroom there.
Rose and his partner Mark Boumansour have a background in wind and solar power installation, so branching into small hydro isn’t a stretch, though they’re some of the first people to do it. “We’re used to talking to municipality and schools that are interested in being in local clean power, like solar in the backyards. Now we’re saying ‘here’s another option,'” Rose says.
The advantage of hydro is that runs continuously (unless the river dries up) and has a long shelf life. While a solar panel might last 25 years, a water turbine might make it to 100.
Also unlike solar or wind, converting a dilapidated dam may actually prettify the environment. “If you don’t develop a solar field on a cow pasture, you just have a cow pasture,” Rose says. “But if you don’t develop [the old mill], you have this empty thing in the middle of your town that can degrade further and potentially become an environmental liability.”
Projects like Chittenden Falls could help preserve history while improving energy resiliency. That doesn’t sound like a bad combination.