Virginia utility Dominion Energy wants to stop observing energy storage from afar.

The utility asked regulators for permission last week to build four battery storage facilities as pilots to test the technology's functionality. After expected completion in 2020, Dominion will study the operations for five years.

That’s a marked advance from Dominion’s position in its original 2018 integrated resource plan, which acknowledged the existence of battery storage but proposed no actions to take advantage of it. "The Company continues to monitor advancements in other energy storage technologies, such as batteries and flywheels,” the IRP stated, while calling for at least 3,664 megawatts of combustion turbine capacity by 2033.

Since then, Dominion has had more time to process Virginia's Grid Transformation and Security Act of 2018, which authorized up to 30 megawatts of utility storage pilots. It was not a mandate, but conveyed legislators’ belief that storage has a role to play in the future of the grid.

In May, data center giants including Apple, AWS and Microsoft wrote an open letter chiding Dominion for neglecting solar power and energy storage in favor of natural-gas capacity. Those companies wield economic clout when choosing where to site new data centers, which consume ample amounts of electricity.

Now the utility wants to build two 2-megawatt/4-megawatt-hour batteries at substations to study batteries as an alternative to expensive grid infrastructure upgrades and as a voltage and power-quality tool. 

A different pair of batteries totaling 12 megawatts/48 megawatt-hours will play a renewables integration role at the Scott solar plant in Powhatan County. One will be DC-coupled and the other will be AC-coupled, to isolate the performance of those different power electronics architectures.

"A pilot is a project that is started in order to get the kinks out and ensure a technology, process or system can scale," said Ben Kellison, director of grid research at Wood Mackenzie Power & Renewables. "These are reasonable because Dominion needs to develop the practices and operational know-how to determine how to size these assets, where they make the most sense and how they interact with their systems."

Renewables influx coming

Utilities elsewhere in the U.S. have moved past the stage of such studies. The island of Kauai, for instance, already runs 40 percent of its evening peak on solar power stored in batteries; utility Arizona Public Service announced plans for hundreds of megawatts of solar to be paired with batteries.

"We certainly follow what other folks have done, but there's nothing like getting the experience yourself," Mark Mitchell, Dominion's VP of generation construction, said in a phone call Tuesday.

He acknowledged that solar time-shifting has been done out West, but said Dominion wants to learn for itself how to respond to variations in weather, and how to operate batteries to maximize system life and roundtrip efficiency.

The utility plans to develop and operate the initial battery systems, but will bid out the engineering, procurement and construction work. Those steps are expected to cost around $33 million.

In the longer term, storage could help Dominion integrate a growing amount of renewable power on the grid, Mitchell said. The utility committed to 3,000 megawatts of new wind and solar capacity by 2022. Dominion also has seen the "duck curve" that hit California's grid as a result of widespread solar adoption, and wants to avoid the steep evening ramp rates that ensued.

The five-year study period puts scaled-up storage development several years behind the arrival of that renewables influx. More deployments could come before then, Mitchell noted.

"I wouldn’t necessarily say we’ll wait for five years — it depends on our experience and how they integrate into our system," he said.


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