For military bases, access to secure and reliable energy is mission critical. A sudden power outage can jeopardize radar systems, air traffic control, and vital operations tied directly to national security. Many bases—especially those in rural communities—rely on local energy grids, and those grids could be vulnerable to damage from extreme weather, natural disasters, or equipment failures. 

To address these risks, the Department of Energy’s (DOE’s) national laboratories teamed up with the National Rural Electric Cooperative Association (NRECA) to enhance energy resilience at a domestic military base.

Recently, researchers from DOE’s Pacific Northwest National Laboratory (PNNL) worked with a rural electric cooperative that serves Ellsworth Air Force Base to install a 277-kilowatt-hour battery energy storage system (BESS). With the new 13,000-pound lithium-ion battery system, the South Dakota air force base will have a safe and reliable backup energy source to support a mission-critical system. The BESS doesn’t just benefit the air force base, either—the nearby Rapid City Regional Airport will also have access to the stored energy in an emergency. 

“This project helped reduce the barriers to entry for other rural electric utilities to deploy lithium-ion batteries by documenting safety and siting considerations around battery energy storage,” said Lauren Khair, senior director of energy research and resilience of NRECA. “The expertise that the national labs brought to the project was invaluable.” 

The PNNL team worked with Sandia National Laboratories, NRECA, West River Electric Association (WREA), the South Dakota School of Mines and Technology, and industry partners. The project was part of the Rural Energy Storage Deployment Program, funded by the DOE’s Office of Electricity and managed in collaboration with NRECA Research. The Rural Energy Storage Deployment Program provided the framework and technical support to enable the development and deployment of the BESS.

National laboratories’ innovations shape the system

Installing the BESS took a multipronged approach. On the ground in South Dakota, WREA provided knowledge to overcome siting challenges and integrate the system into Ellsworth’s infrastructure, while NRECA offered additional technical guidance. Both organizations relied on PNNL’s and Sandia’s expertise to implement best practices across all aspects of the project, including system design, safety protocols, operational resilience, and integration with existing infrastructure. 

PNNL and Sandia addressed an early challenge in designing the BESS: the lack of detailed historical energy data from the base. To understand how much energy storage the base needed, researchers needed to understand the base’s expected energy use, such as times during the year when demand might be high or low. The research team developed a synthetic one-year dataset that replicated Ellsworth’s energy use patterns in 15-minute increments, accounting for seasonal changes, daily fluctuations, and weekday versus weekend variations. 

“The dataset provided the essential inputs needed to assess resilience and determine the appropriate size for the energy storage system,” said Di Wu, a power system research engineer at PNNL.   

To address safety concerns, the BESS incorporates PNNL’s IntelliVent technology, a safety system that helps prevent explosions in energy storage systems, should a significant failure occur. The system uses sensors to detect gas buildup inside the battery enclosure. If IntelliVent detects a problem, the system automatically opens doors to release the gas and reduce the risk of explosion. The Ellsworth project marks the first time this technology has been deployed in a newly built system rather than as a retrofit. 

The BESS was also integrated with existing diesel generators to address inefficiencies from using too much fuel. The PNNL team demonstrated that coordinating the BESS and generators optimizes operations by cutting wasted energy and improving fuel efficiency. This improvement extends the fuel supply’s duration, increasing the system’s resilience by allowing it to operate through longer outages. 

“Partnerships are essential for driving innovation in rural energy systems, particularly for electric cooperatives like WREA,” said Adam Daigle, energy services advisor of WERA. “With limited budgets and resources, cooperatives often don’t have the funding or expertise needed to take on advanced projects like battery energy storage systems on their own.”

Supporting rural energy resilience

While the BESS directly supports Ellsworth’s energy resilience, its impact extends beyond the base. Ellsworth Air Force Base, home to the 28th Bomb Wing and future B-21 Raider aircraft, is a major economic driver for western South Dakota, contributing $799 million annual economic impact to the region. The BESS not only strengthens energy resilience for critical operations but also supports the base’s role in the region. 

As a demonstration project, the Ellsworth BESS provides valuable insights for the development of future energy storage systems. The battery’s ability to withstand future weather extremes will provide insight into how conditions affect energy degradation and charging efficiency. Data collected for the system will help researchers and agencies refine energy storage technologies to serve other rural communities. Recognized with an Air Force Community Partnership Award, the project demonstrates how federal, local, and industry partners can collaborate to address complex energy challenges, creating a scalable model for future deployments.

The demonstration also enhances the base’s energy resilience with explosion prevention, cybersecurity protection, and seamless islanding.

“The success of this project reflects the power of partnerships,” said Vince Sprenkle, the director of the Grid Storage Launchpad at PNNL. “Bringing together expertise from [the Department of Defense], DOE, national labs, and the private sector has created a model for resilient, efficient energy systems that can be replicated nationwide.”