New research from national labs in the US has demonstrated that smaller scale run-of-river (ROR) hydropower can provide just as much baseload stability as reservoir-based hydropower plants while being highly responsive to real-time grid and market changes.

As with wind and solar, ROR hydropower generates power intermittently, based on how much water is flowing on any given day. Integrated, a project funded by the US. Department of Energy’s Water Power Technologies Office, is exploring new ways of using energy storage devices such as batteries, flywheels and supercapacitors to add storage to ROR hydropower plants. Integrated storage could enhance ROR power by making it possible to ramp power up or down on demand.

Phase I of the Integrated project confirmed the idea that ROR hydropower combined with energy storage systems can be as responsive as reservoir-based hydropower. One test case demonstrated the potential for the technology to increase ROR hydropower revenue by 12% to 16% due to the additional services that the ROR hydropower plants could provide to the grid.

For example, ROR hydropower owner/operators could sell electricity to the grid at the most opportune times and avoid having to drop their price when demand is low.

ROR hydropower plants with integrated storage systems could also be compensated for helping improve grid stability. A service known as frequency regulation can help prevent brownouts when a transformer faults or, say, 10,000 people get home from work at the same time and turn on their AC. Storage systems at ROR plants would be able to rapidly discharge electricity to respond to supply or demand fluctuations.

Phase II of the project will include two field demonstrations of the technology. The first field demonstration will be a black start test to demonstrate that ROR hydropower plants with energy storage can restore electric power without assistance from the transmission system. Lessons from the field demonstrations, with Idaho Falls Power and another utility, will be used to refine the technology and ultimately prove its reliability under real-world conditions.

The black start test will involve Idaho Falls Power, a city-owned utility with four ROR hydropower plants on the Snake River near where INL is headquartered. Black start capability is essential for small hydro to be able to operate a microgrid to power critical loads in the event of an extended large area outage. The test will investigate how much energy storage is needed to provide adequate frequency and voltage stabilization for a system during a black start.

Idaho National Laboratory is leading the project, with Argonne National Laboratory and the National Renewable Energy Laboratory taking part in the Integrated work.