The Tesla name evokes images of sleek electric cars and eccentric billionaires.
In Soldotna, a fleet of Tesla batteries is helping with a more mundane but important task— regulating the Kenai Peninsula’s supply of electricity.
Larry Jorgensen is director of power, fuels and dispatch at Homer Electric Association. On a frosty afternoon outside the utility’s generation facility in Soldotna, he walked through rows of padlocked white containers, stamped with the red Tesla logo and containing lithium-ion batteries.
"Each Megapack has about 2.5 megawatts of storage in it,” he said. “And then there’s 37 of them altogether.”
That’s enough to power 925,000 100-watt light bulbs.
Or, in Tesla terms: “I think Brad Janorschke, our general manager, uses the example that this is the equivalent of 970 Tesla cars parked out here, charging and discharging,” Jorgensen said.
The Tesla batteries are part of Homer Electric Association’s battery energy storage system, or BESS — a facility that stores a constant supply of power for the utility’s grid.
Staff and board members from the utility cut the ribbon on the BESS facility at a ceremony this week. But the BESS has been up and running since January.
Jorgensen said its biggest use is to regulate Homer Electric's system. He said the system gains about 10 percent fuel savings with the BESS.
“You can imagine if you’re driving your vehicle on the road, if you are constantly accelerating, deaccelerating, it’s not going to be a very efficient way to drive,” he said. “So by doing this, we can drive the power plants at a very constant rate and let the BESS take the changes.”
It has other uses, too.
The BESS is a backup power source if Homer Electric's system goes off line. For example, if a wildfire damages transmission lines, the batteries can still store energy for later use.
David Thomas, director of strategic services at Homer Electric, said the BESS also has the potential to stabilize irregular renewable energy sources, like solar and wind. Batteries could capture that energy in times of surplus for times when there’s less available.
That will help with the utility’s goal of diversifying its sourcesof energy from the natural gas its mostly reliant on today. Homer Electric already has a hydroelectric project at Bradley Lake, across Kachemak Bay, which supplies the utility with about 15% of its energy needs. Now, it’s looking into incorporating solar power onto its grid, through a 2-megawatt solar farm from a private producer.
Homer Electric isn’t the only utility using the BESS technology to avoid blackouts and increase efficiency.
Golden Valley Electric, the utility in Fairbanks, has been using its battery system for almost two decades. When it came online in 2003, it was thelargest battery in the world. Golden Valley’s battery today is nearing the end of its lifespan.
Thomas said since Golden Valley brought its system online, system price points and capacity have improved dramatically.
“This unit is eight times larger and is in no way the largest anymore," he said. "This is a run-of-the-mill energy storage system, as batteries go around the world now.
Tesla, for its part,says its battery pack technology is in high demand nationwide, as more utilities are turning toward renewable energy.
