As Virginia pushes towards one of the US’s most ambitious energy storage targets, pilot battery storage projects have been brought online from the state’s biggest investor-owned utility (IOU).
At the time it passed into law in 2020, Virginia’s target to deploy 3.1GW of energy storage on the grid by 2035 was the biggest of its kind in the nation, aimed at facilitating 100% emissions-free electricity in the state by 2050.
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Although the target has since been surpassed by New York Governor Kathy Hochul doubling a 3GW target by 2030 for that state to 6GW, Virginia’s target remains comfortably at the higher end of targets and goals set in the 10 US states so far to have adopted them.
Virginia’s utilities have been instructed to deliver that rollout, with the state setting various rules and frameworks to enable it in early 2021. As the biggest investor-owned utility (IOU) operating in the state, Dominion Energy has to put 2,700MW of that total 3.1GW into service by the middle of the next decade.
In 2019, shortly before the target was set, Dominion had said it would build pilot battery energy storage system (BESS) projects adding up to 16MW of output. The pilot was enabled by an earlier piece of legislation, the 2018 Grid Transformation and Security Act, which let the utility invest in up to 30MW of BESS.
Approval for those projects from the State Corporation Commission came a few months later.
At that time, in February 2020, Dominion Energy Virginia said it aimed to commission the four projects by the first quarter of 2021, but of course the COVID-19 pandemic was declared shortly after that. Dominion said the pilots would cost a total of US$33 million.
Last week, Dominion Energy Virginia announced that the largest among its pilot projects has just been commissioned.
Virginia projects try out different applications and configurations
It comprises three independently operating BESS at the same site, adding up to 12MW output. According to renewable energy and energy storage company RES, which delivered the project for Dominion, the storage capacity of the three combined systems is 48MWh.
RES’ Scott Battery Energy Storage System pilot is paired with Scott Solar, an existing solar PV facility in Virginia’s Powhatan County.
It includes one AC-coupled BESS of 10MW/40MWh (four-hours’ duration) to help Dominion match peak load with peak production, i.e. storing energy for when it is most needed by the grid.
The AC-coupled system uses CATL battery cells, Dynapower power conversion system (PCS) and other power electronics with RES’ own energy management system (EMS) controller, RESolve.
The other two BESS at the Scott project are DC-coupled, each one of 1MW/4MWh that demonstrate the ability of the DC-coupled configuration to capture electricity generated at the solar power plant’s peak production, which is otherwise lost.
While battery and PCS providers were not disclosed by RES for the two smaller systems, the company did say it integrates the DC-coupled technology into the solar plant’s existing inverters, using a custom-made solution developer by RES, EVS and ConnectPV.
RES’ Americas CEO John Rhode said the Scott project “paves the way for additional energy storage projects needed to support a carbon free future,” calling it a milestone project for both RES and Dominion in Virginia.
Dominion noted that in addition to the project at Scott Solar, the pilot project portfolio includes two more sites: both are 2MW/2MWh BESS installations at substation sites.
One is in the Hanover County town of Ashland and will demonstrate that BESS technology can be used to bolster the existing grid and allow Dominion to keep serving customers in a region of growing demand without needing to make expensive transmission and distribution (T&D) infrastructure upgrades.
The use case is what has been called the application of batteries as a ‘non-wires alternative’ to those upgrades. The Hanover County project is scheduled to come online later this year.
The other 2MW BESS has already been online since February at a substation in Virginia’s New Kent County. Paired with a 20MW solar PV plant, the system serves to demonstrate how batteries can help manage voltage and loading issues that can be caused by reverse energy flow.
Dominion noted that in March the Virginia State Corporation Commission also approved Dry Bridge, a 20MW BESS project in Chesterfield County and a 50MW BESS project paired with 100MW solar PV at Dulles International Airport, Loudoun County alongside utility-scale and distributed solar PV projects totalling about 1GW.