Successful Schofield test demonstrates our energy future

by Donica Kaneshiro | Aug. 4, 2021

Reliable, renewable and resilient power are concepts we use a lot when talking about the future of our company. A recent test proved that those concepts aren’t just lofty ambitions but attainable goals.

Our company partnered with the U.S. Army to demonstrate Schofield Generating Station’s ability to temporarily detach from the grid and power a microgrid consisting of three Central Oahu Army installations within two hours of a catastrophic event, such as an island-wide blackout, hurricane or an attack. The inaugural test was a defining moment for the power plant that was conceived more than eight years ago and represents a unique partnership between the Army and our company, in which we lease land at Schofield in exchange for a promise of energy security in times of crisis.

“That was really, really, really gratifying to see everybody come together and all the equipment work as designed, all the people trained and ready, all the procedures going as planned, and everybody pulling in the same direction,” said Jack Shriver, director of Generation Project Development.

The test on May 22 required us to shut down power to Schofield Barracks, Wheeler Army Airfield and Field Station Kunia and perform switching on both our side and the Army’s side of operations. Using the plant’s “black start” capability, the team then began to generate power for the three-base microgrid.

A black start unit can restart its own power from the plant’s generators in the event of a blackout without relying on an external transmission network.

After operating as a microgrid for 36 hours, the process was reversed. The bases were blacked out again, switches were reconfigured and power was restored from the grid.

“It was really a confluence of a lot of good ideas that came together from different stakeholders from the Army’s perspective, from the Wahiawa community’s perspective, from the company and system operations, from the union,” Jack said. “There were a lot of folks that each added their own contribution.”

When it came time to power down the bases, backup was ready in case anything went wrong.

Operations engineer Michelle Sakata works in System Operation and assisted with the Control System Acceptance Test (CSAT) to verify data coming from power plants, like Schofield, to our Energy Management System (EMS) is correct and the controls are working properly.

On the day of the test, Michelle was a part of the team of employees on standby to ensure the test went smoothly. “We tried to be as prepared as we could be,” she said.

With the deadline quickly approaching for our company to assume responsibility for the distribution systems on the Army’s 12 installations on Oahu, the some employees used their time on base to gain experience and knowledge of the Army’s systems.

“Once the utility privatization contract goes into effect this fall, it will be Hawaiian Electric troublemen out there at the substations, doing that work. So we also took advantage of that opportunity to get our guys out there with the Army guys during this test to get a feel for what that’s going to be like, what the equipment looks like, how it operates, what the different loads are, the status of the equipment,” Jack said.

Islanding Schofield Generating Station has two major impacts on the system. While operating as a microgrid, it is unavailable as a resource to the rest of the grid, so the load needs must be accommodated alternatively, and communities that normally draw power through those 46kv lines within the microgrid need to be switched to a second circuit. All of this should be seamless to our customers outside the microgrid, as it was on the weekend of the test.

“The generation scheduler had to account for the test in how generation was scheduled for that weekend to make sure that the reserves that we carried on the rest of systems were correct,” Michelle said.

Jack said all new procedures and policies were required to plan for the microgrid.

“Our employees are embracing the change and embracing the uniqueness of this and seeing that there might be more things like this in the future,” he said. “It has taken a lot of cooperation across the company to make this all happen.”

Because of the unique agreement with the Army, it has sometimes proven a challenge to make those in the community understand the benefits Schofield holds for all customers.

As the most fuel-efficient power plant on our system, it saves other power plants from having to burn fossil fuels and its flexibility allows us to integrate more renewables on the grid. Also, because it is quick-starting, with units ramping up in about 90 seconds, it serves as online reserves, even when it isn’t burning any fuel.

Although the plant can use diesel fuel, Schofield has operated using only 100% locally refined biodiesel since placed in service three years ago. It’s also the only power plant at an elevation and away from the coast lines, making it less vulnerable to storms, sea level rise and tsunamis.

The microgrid capabilities are not just a boon for the Army but Central Oahu and the entire state. In the event of a hurricane or other disaster, the microgrid could be incrementally broadened to include, for example, Wahiawa General Hospital, in accordance with our critical infrastructure restoration plans.

It could also provide power to Wheeler Army Airfield, which is the only airfield located away from the coastline, Jack said. In a disaster response scenario, FEMA and the Hawaii Army National Guard could reach those in need across the state by basing out of Wheeler.

The Army partnership at Schofield has garnered interest from other military bases in the islands and beyond. With the new microgrid tariff and the approaching 2045 goal of 100% renewable electricity, Jack says he anticipates more company-owned and third-party micro grids.

“So there’s not just energy resilience, but real, statewide, disaster response resilience capability that Schofield provides,” Jack said.

Donica Kaneshiro is a communications consultant at Hawaiian Electric Company.



Established in 1891, Hawaiian Electric is committed to empowering its customers and communities by providing affordable, reliable, clean and sustainable energy.

Hawaiian Electric

Established in 1891, Hawaiian Electric is committed to empowering its customers and communities by providing affordable, reliable, clean and sustainable energy.