Douglas County PUD plans to launch a hydrogen electrolysis pilot project later in 2019 that could help smooth out mechanical operations at its hydroelectric facilities, and in the process blaze a trail for renewable hydrogen in Washington.
The PUD wants to acquire at least one 2-3 MW hydrogen electrolyzer—a device that splits water into hydrogen and oxygen using electrolysis—which it hopes to have on line by summer 2021.
The utility is taking sealed bids for the equipment through Oct. 7. The project is expected to cost between $3 million and $6 million, PUD General Manager Gary Ivory said.
The main use for the electrolyzer will be to help smooth out mechanical operations at its hydroelectric facilities. The unit, though, could be put to multiple uses, he said.
Water and excess generation can be dumped into the electrolyzer, which splits the water into hydrogen and oxygen, to reduce the extent of adjustments made every four seconds at its hydropower plants to balance its system. That will significantly reduce wear and tear on equipment. An electrolyzer can ramp up and down in microseconds and with much less mechanical effort than a hydropower plant.
“We need to be able to capture some of the energy variabilities we see and also to increase hydroelectric efficiency,” Ivory said.
The utility is focused on proton exchange membrane (PEM) electrolysis, which can ramp up and down faster than the other electrolysis technologies—alkaline and solid oxide. It also requires less hands-on oversight, he said.
The produced hydrogen can be put to myriad uses, such as ammonia production for fertilizer or for hydrogen-fueled vehicles. In fact, Douglas plans to add hydrogen-fueled vehicles and a fueling station shortly after the electrolyzer goes on line, Ivory said.
The utility has spent several years exploring several emerging energy technologies that could complement hydropower, and determined that electrolyzers were affordable, particularly compared to pumped storage, which was prohibitively expensive. PUD engineers visited several electrolyzer manufacturers to help focus the pilot project’s scope.
While the project envisions a single unit, it has room to grow. “The [draft] bid document contemplates different levels of expansion,” Ivory said. “It could be up to 20 MW.”
The project was made possible by passage earlier this year of Senate Bill 5588, which authorizes PUDs to produce, distribute and sell renewable hydrogen. The hydrogen is considered renewable if both the water and the energy source used to produce the gas are renewable.
Millions of tons of hydrogen are produced each year in the U.S., mostly for use in oil refining, and production of fertilizer and steel. Almost all of it is made using natural gas, thus creating significant carbon emissions, said Ken Dragoon, executive director of the Renewable Hydrogen Alliance and a veteran of the Northwest power industry.
Eliminating greenhouse gas emissions is one benefit to pairing electrolysis with renewable generation. But that is not what makes Douglas' proposed project innovative, he said.
The utility's “brilliant idea is to use electrolyzer loads as contingency reserves, because they can be cut as fast—or faster—than generation,” Dragoon said. “In other words, instead of ramping up generation when there is a system outage, we can cut load.”
That means generation resources do not have to be run below capacity to safeguard against system outages.
“This has the potential of freeing up significant generating capacity in the region as concerns over capacity increase due to closing coal plants. Ironically, the answer to a shortfall in capacity may be to add electrolyzer loads,” Dragoon said.