Shortly before noon on Thursday, Idaho Falls Power workers flipped the switch on the city's lower power plant.
Far below, the gates opened, bringing thousands of gallons of water from the Snake River through the turbines. As the turbines spun up, the power generated by the water didn't go directly into the city power grid. The electricity was channeled into two blue tractor trailers just off Sunnyside Road that housed a supercapacitor and high-energy power banks.
The exercise was part of a weeklong test done in a collaboration between Idaho Falls Power and Idaho National Laboratory to see whether the city could have a self-sustaining power grid in the event of a blackout or regional emergency. The data gathered over the tests could lead to Idaho Falls establishing one of the world's first water-powered microgrids.
"We're in a great position to leverage our power system and INL's power-related mission to collaborate on this proof of concept," Idaho Falls Power General Manager Bear Prairie said.
The partnership on the microgrid has been in the works since 2015. The interest was partly in response to a December 2013 power outage triggered by a botched circuit breaker repair at the Goshen substation near Firth, that left tens of thousands of residents powerless for hours in freezing temperatures.
Thursday morning's test, involving the lower power station off Sunnyside and the Old Lower power plant further south of town, was the public version of the weeklong testing process attended by Idaho Falls city officials and local media. A microgrid could provide up to 20% of Idaho Falls' regular demand for a brief time, with the focus on keeping critical city systems online.
"This would be enough to keep our hospitals powered, to keep our water system safe. It could allow us to keep a few schools open, if something happens during the winter and we need to power centers for the community," Mayor Rebecca Casper said.
Microgrids are local energy systems that can operate as part of a larger power system in normal conditions, then break off as a self-sustaining unit during a crisis. Most microgrids currently in use power single facilities or regions, but cities are increasingly looking into their potential as an emergency backup.
Ning Kang runs the power and energy systems department at INL. Kang said the challenge with getting a microgrid established is that most elements of a power system are designed to operate as part of a large-scale system.
"For most generators, if they don't see the normal demand of power they won't be able to kick on. We need to provide that support for a local system," Kang said.
Idaho Falls isn't the only community that has worked with the lab on creating a microgrid. INL helped test the microgrid for the Blue Lake Rancheria tribal government in California, which went live in March 2020. The Blue Lake grid relies on solar power and Tesla battery storage to power the 100-acre reservation.
The lab provided a supercapacitor to the power grid for Thursday's simulation. The supercapacitor works like a battery to temporarily store power and can handle high amounts of voltage and current for brief windows of time.
In the bowels of the lower power plant, Matt Roberts sat in front of a laptop monitoring the power supply. Colored lines jumped up and down on the screen as the power plant workers tried different configurations of the two power plants and varied the level of demand. A thin blue line showed that throughout the changes, the power system was able to fully match the demand.
Roberts, who manages hydroelectric power projects for Emerson Electric, said this was the first real-world test of a microgrid power system he'd attended in 15 years of work in the industry.
"Generally we only test these as a computer simulation, where all the changes are clean and the lines are smooth. We can get so much more from tracking the real effects of water and demand," Roberts said.
The test run couldn't pull the electricity into the broader city grid and risk affecting customers. Idaho Falls Power brought in the two giant load banks that plugged directly into the power grid. Each bank can take in up to four megawatts of power — enough to power more than 1,000 homes for an hour — and convert it into heat, providing a simple but practical outlet for the sheer volume of electricity being tested.
After this week's tests on the system, INL and the power company will evaluate the data to determine how close the microgrid is to becoming a reality. Idaho Falls would need to purchase its own supercapacitor eventually bring the system online.