Approval for utility Alliant Energy’s battery storage additions to Wisconsin solar PV plants

By Andy Colthorpe


Artist rendering of a battery storage asset of the type to be deployed by FlexGen for Alliant Energy. Image: Alliant Energy.

US utility Alliant Energy’s plans to build two large-scale battery storage projects to pair with solar PV plants in Wisconsin have been approved by regulators.

The company said last week (9 August) that the Public Service Commission Wisconsin (PSCW) has given the green light to its proposals for Alliant Energy’s Grant County Battery Project and Wood County Battery Project.

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Each will be integrated with a large-scale solar PV plant also bearing the name of their respective host counties.

The Grant County battery energy storage system (BESS) will be 100MW output, integrated with the 200MW Grant County Solar Project. The PV plant is currently under construction in the Grant County town of Potosi, and is expected to go into commercial operation in H1 2024.

Meanwhile Wood County’s BESS will be 75MW, integrated with the 150MW Wood County Solar Project that already went into operation in late 2022, in the town of Saratoga.

As reported by sister site in October 2022 when Alliant Energy revealed it was seeking the PSCW’s approvals, both BESS assets will be 4-hour duration, making Grant County 100MW/400MWh and Wood County 75MW/300MWh for a total of 175MW/700MWh.

Also reported at the time was that energy storage system integrator FlexGen was selected by the utility to work on the projects. Alliant confirmed yesterday that this is the case, with FlexGen to provide both energy management system (EMS), based on the company’s HybridOS operating platform, as well as battery storage hardware.

Alliant, which supplies both electricity and natural gas to retail customers, is targeting carbon neutrality across its electricity business by 2050. This commitment is part of the company’s ‘Clean Energy Vision’ which pledges to reduce greenhouse gas (GHG) emissions 50% relative to 2005 levels by 2030, and eliminate coal from its generation fleet by 2040.

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