Energy management: Duke Energy has started testing a first-of-its-kind battery technology at its Rankin Substation in Gaston County, N.C. The hybrid ultracapacitor-battery energy storage system (HESS) will demonstrate multiple service applications: extended operational life, rapid response, real-time solar smoothing and load shifting.
"This approach will allow our energy storage systems to do a variety of tasks," said Thomas Golden, technology development manager for Duke Energy. "With so many solar installations in North Carolina, we must look for innovative ways to better incorporate renewable energy into our system – and still provide reliable service at a competitive price for our customers."
One of the distribution lines at the substation has a 1.2-megawatt solar installation connected a mile away. With North Carolina fourth in the nation for installed solar power, managing and maintaining these grid-connected renewable installations is critical now and in the future, added Golden.
"Energy storage is changing the paradigm on how we generate, distribute and use energy. The demonstration of new technologies will help facilitate wider adoption across the nation," said Matt Roberts, executive director of the Washington, D.C.-based Energy Storage Association. "Duke Energy is to be commended for its work on this project and partnership efforts in advancing energy storage solutions."
Duke Energy is a national leader in battery storage among utilities. The company will be the host utility for the Energy Storage Association's annual conference in Charlotte, April 25-27.
Rankin is no stranger to innovation. In 2013, an earlier battery installation at the site was named Project of the Year by the editors of POWERGRID International magazine and PennWell Corp.
For the current project, which went operational last month, Duke Energy partnered with several other companies:
• Aquion Energy is providing the innovative battery technologies and associated engineering services.
• Maxwell Technologies is providing fast-response ultracapacitors (UCAPs) that are capable of storing and discharging energy quickly and effectively.
• Win Inertia is providing the SHAD® solution (Win Inertia's HESS) integrating enhanced power electronics and patented energy management and control systems.
The HESS system will use UCAPs to help manage solar smoothing events in real-time – particularly when the solar power on the grid fluctuates due to cloud cover or other weather circumstances. UCAPs have been proven in other applications to reduce heat stress on the battery and minimize degradation. The batteries will be used to shift solar load to a more advantageous time for the utility.
Win Inertia's hybrid energy storage system (SHAD®) is based on a flexible hardware and software platform that enables the seamless operation of Aquion's batteries and Maxwell's UCAPs in the same energy solution. The hybrid energy storage integrates patented energy management algorithms. This helps integrate energy storage technology to provide simultaneous and cost effective grid services.
Maxwell UCAPs discharge and recharge power in the sub-second to minutes timeframe, with long operational life in a wide operating temperature window. This is ideal for stabilizing short-term PV power output fluctuation in large-scale deployments. This ensures reliable access to solar power on the grid.
The 100-kilowatt/ 300-Kwh battery uses a unique Aqueous Hybrid Ion chemistry. This includes a saltwater electrolyte and synthetic cotton separator. These materials should result in lower costs, while the water-based chemistry will provide a non-toxic and non-combustible product that is safe to handle and environmentally friendly.
About Duke Energy
Headquartered in Charlotte, N.C., Duke Energy is a Fortune 125 company traded on the New York Stock Exchange under the symbol DUK.