Software-focused battery energy storage system (BESS) integrator FlexGen has put two utility-scale BESS projects in operation in Wisconsin and Iowa, US, totalling 700MWh.
FlexGen designed and built the BESS for utility Alliant Energy. The 75MW/300MWh Wood County BESS, situated in Saratoga, Wisconsin, is on land next to Alliant Energy’s 150MW solar field. Alliant says Wood County will bring its planned and operational energy storage in Wisconsin to 275MW.
Situated in Southeast Iowa, the 100MW/400MWh Wever BESS is located on land next to a separate Alliant Energy 150MW solar PV plant. Upon completion of three other projects, Alliant says Iowa’s total planned battery storage capacity will reach around 400MW.
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.
Try Premium for just $1
- Full premium access for the first month at only $1
- Converts to an annual rate after 30 days unless cancelled
- Cancel anytime during the trial period
Premium Benefits
- Expert industry analysis and interviews
- Digital access to PV Tech Power journal
- Exclusive event discounts
Or get the full Premium subscription right away
Or continue reading this article for free
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.
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 US 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 100MW/400MWh BESS, next to a 200MW 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.
The Energy Storage Summit USA will be held from 24-25 March 2026, in Dallas, TX. It features keynote speeches and panel discussions on topics like FEOC challenges, power demand forecasting, and managing the BESS supply chain. ESN Premium subscribers can get an exclusive discount. For complete information, visit the Energy Storage Summit USA website.
