Alliant Energy has successfully integrated its first 100-megawatt Battery Energy Storage System (BESS) in Grant County, Wisconsin, marking the company's largest battery energy storage installation to date. The system became operational on October 16, 2025, positioned next to the company's existing 200-MW solar project in the Town of Potosi.

System Capabilities and Operations

The newly operational battery system captures and stores excess energy generated by solar and other resources, then releases the energy to the grid as needed. When demand is low, excess electricity is stored by the battery and released when required. The BESS system can power over 100,000 homes for up to four hours on a single charge. The energy storage system operates by storing electricity during periods of low demand and releasing it when the grid requires additional power. This functionality allows the battery to complement Alliant Energy's existing generation resources while providing enhanced grid flexibility.

Strategic Integration and Grid Benefits

David de Leon, president of Alliant Energy's Wisconsin energy company, stated that energy storage systems serve as an important step toward creating a more intelligent and resilient grid. He emphasized that the combination of BESS and solar represents a critical component of the company's balanced energy portfolio, offering value and flexibility while ensuring reliable and cost-effective energy availability for customers.

The battery storage system is designed to improve grid reliability, resiliency, and efficiency. It positions Alliant Energy to meet demand, reduce the need for traditional power grid updates, and ensure preparedness for outages and severe weather conditions. The system also helps optimize energy resources, including wind, solar, hydro, and traditional generation systems.

Economic Impact and Customer Savings

Battery technology installations are escalating and setting new records in the United States, while generating customer savings. A recent analysis demonstrated that releasing stored energy when the grid needs it most saved Texans an estimated USD 750 million. Alliant Energy customers could expect similar savings through avoided costs as additional BESS projects become operational.

The energy storage infrastructure represents a newer component of Alliant Energy's strategy and serves as a key element in bolstering their investments in renewable energy. These efforts aim to keep customer rates as low as possible while maintaining service quality.

Company Background and Future Plans

Adding battery storage forms part of Alliant Energy's comprehensive Energy Blueprint, which serves as the company's roadmap for advancing their balanced energy mix. As the electric grid continues to evolve, the company positions itself as a leader in providing innovative solutions and integrating emerging technologies. Alliant Energy Corporation provides regulated energy service to approximately 1 million electric and 430,000 natural gas customers across Iowa and Wisconsin.

The company's mission focuses on delivering energy solutions and exceptional service that customers and communities count on safely, efficiently, and responsibly. Interstate Power and Light Company (IPL) and Wisconsin Power and Light Company (WPL) operate as Alliant Energy's two public energy companies. The Grant County battery installation represents Alliant Energy's commitment to expanding energy storage capabilities as part of their broader renewable energy investment strategy.

The project demonstrates the company's approach to integrating advanced battery technology with existing solar generation facilities to create a more comprehensive and flexible energy system.

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