US utility Vistra has brought a 260MW/260MWh battery energy storage system (BESS) online in Texas, the largest in the state.
Vistra said yesterday (23 May) that the DeCordova Energy Storage Facility in Granbury, near Dallas, is online and participating in the wholesale energy markets on the ERCOT grid, the operator for the state.
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The BESS is co-located on the site of the natural gas-fueled DeCordova Power Plant, operated by Vistra’s subsidiary Luminant. It will capture excess electricity from the grid, particularly overnight during hours of high wind production, and release the power in hours of peak demand.
It uses containerised lithium-ion batteries with 3,000 individual modules. Vistra has not revealed the supplier of the modules (it used LG Energy Solution for its Moss Landing Energy Storage Facility BESS, the largest in the world) but said that Sungrow supplied the inverters while engineering firm Mortensen provided “engineering and construction expertise”.
Jim Burke, Vistra president and chief financial officer, commented: “DeCordova offers a unique value proposition – not only can this battery system provide instantaneous full power to the grid with the flip of a switch, but it is also co-located on the same site as our quick-start DeCordova natural gas-fueled power plant.”
“This pairing means we essentially have a large, one-hour battery system with dispatchable, reliable generation, leading to continuity of operation and resiliency of the grid. In addition, these gas-fueled generation units have seven days of diesel backup in the event of any disruption of natural gas supplies, which is yet another example of the resiliency aspect of the DeCordova site.”
The DeCordova project was announced in 2020 by Vistra as part of a total 1GW of solar and energy storage planned by the company in the ERCOT market, as it prepares to retire 6.8GW of coal-fired power plants in Texas by 2027.
ERCOT is a completely decentralised energy market with no centralised capacity auctions like the UK’s Capacity Market or California ISO’s resource adequacy, meaning generators make all their money through energy trading and some ancillary grid services.
With some 45GW of renewable energy resources online in the state as of end-2021 according to American Clean Power, there is plenty of price volatility for BESS operators to capitalise on. Energy trading may be as much as half of BESS revenues now according to investor Gore Street Capital, while grid services like Responsive Reserve Service (RRS) and Firm Frequency Response (FFR) make up the rest.
Based on figures from ERCOT at the end of 2021, there is likely to be somewhere between 1,300-2,800MW of grid-connected storage in Texas at the time of writing. Although Vistra’s announcement mentioned the approaching hot Texas summer, it was the devastating winter storm of February 2021 that is talked about as a pivotal moment in demonstrating the role storage can play on the state’s grid.
Vistra is aiming to bring its zero-carbon portfolio to nearly 3,300 MW online by this summer and more than 7,300 MW by 2026, which includes Moss Landing in California. The company plans to expand the Moss Landing Energy Storage Facility project from 1,600MWh at present to 3GWh, although it has had some problems with the plant since it went online in early 2021. Overheating in some modules took it offline a few months after inauguration.