FlexGen Begins Operating 700MWh Total BESS in Wisconsin, Iowa for Alliant Energy

Why It Matters

The new storage assets give Alliant Energy greater grid flexibility and a faster path to its 2030‑2050 decarbonization goals, while cementing FlexGen’s position as a leading BESS integrator.

Key Takeaways

• FlexGen commissioned 700 MWh BESS for Alliant Energy.
• Wood County: 75 MW/300 MWh beside 150 MW solar.
• Wever: 100 MW/400 MWh adjacent to 150 MW solar.
• Storage boosts grid flexibility, defers new transmission builds.
• FlexGen acquired Powin IP, expanding its EMS capabilities.

Pulse Analysis

The deployment of 700 MWh of battery storage marks a significant step in the Midwest’s transition toward renewable‑heavy grids. By pairing large‑scale BESS with existing solar farms, Alliant Energy can smooth intermittent generation, shift energy to peak periods, and reduce reliance on costly transmission upgrades. FlexGen’s HybridOS platform provides real‑time optimization, enabling operators to respond instantly to load fluctuations and maintain system reliability, a capability increasingly demanded by utilities facing higher renewable penetrations.

FlexGen’s strategic acquisition of Powin’s intellectual property in 2025 amplified its competitive edge. The deal added a suite of proven hardware designs, advanced control algorithms, and a spare‑parts inventory, allowing FlexGen to offer end‑to‑end solutions without reinventing core components. Integrating Powin’s field projects into FlexGen’s Remote Operations Center also expands its service footprint, positioning the company as a one‑stop shop for utilities seeking scalable, software‑driven storage deployments across the United States.

For Alliant Energy, the new BESS installations are integral to an ambitious emissions roadmap that targets a 50 % reduction by 2030 and a coal‑free portfolio by 2040. Battery storage not only captures excess solar output but also provides ancillary services such as frequency regulation and voltage support, essential for maintaining grid stability as fossil‑fuel generation declines. The projects illustrate how coordinated storage‑solar pairings can accelerate utility decarbonization while delivering economic benefits to ratepayers, a model other regional utilities are likely to emulate.

FlexGen begins operating 700MWh total BESS in Wisconsin, Iowa for Alliant Energy

By April Bonner · February 9, 2026

Software‑focused battery energy storage system (BESS) integrator FlexGen has put two utility‑scale BESS projects in operation in Wisconsin and Iowa, US, totalling 700 MWh.

FlexGen designed and built the BESS for utility Alliant Energy. The 75 MW/300 MWh Wood County BESS, situated in Saratoga, Wisconsin, is on land next to Alliant Energy’s 150 MW solar field. Alliant says Wood County will bring its planned and operational energy storage in Wisconsin to 275 MW.

Situated in Southeast Iowa, the 100 MW/400 MWh Wever BESS is located on land next to a separate Alliant Energy 150 MW solar PV plant. Upon completion of three other projects, Alliant says Iowa’s total planned battery storage capacity will reach around 400 MW.

According to Alliant, both BESS are continuously monitored 24/7, enabling operators to respond immediately to performance changes. The utility also collaborated with local fire departments to prepare for any incidents at either site.

By storing and releasing solar‑generated energy, these BESS facilities provide Alliant Energy with increased flexibility and help prevent customer costs associated with equipment replacement or constructing new lines and poles to meet rising energy demands.

Alliant announced plans to deploy two projects, including the Wood County BESS, in Wisconsin, in 2022.

FlexGen is also providing system integration services using its HybridOS energy‑management software (EMS).

In August 2025, court approval was granted for FlexGen’s acquisition of assets from its bankrupt competitor, Powin. The U.S. Bankruptcy Court for the District of New Jersey, overseeing Powin’s Chapter 11 case, approved FlexGen’s proposal to purchase a significant portion of Powin’s operations.

This deal allowed FlexGen, based in North Carolina, to acquire all of Powin’s intellectual property, including hardware, software, and IT systems.

Additionally, FlexGen purchased Powin’s spare‑parts inventory, and Powin’s field projects will now connect to FlexGen’s Remote Operations Center (ROC). HybridOS and its controls software will also be provided to Powin’s customers.

In October 2025, Alliant Energy in Wisconsin integrated its first 100 MW/400 MWh BESS, next to a 200 MW solar project in Grant County.

By 2030, the company aims to cut greenhouse‑gas emissions from its utility operations by 50 % compared to 2005 levels.

Alliant plans to phase out all coal from its generation fleet by 2040 and intends to reach net‑zero greenhouse‑gas emissions from its utility operations by 2050.