Grid-scale batteries become more popular every day as the world looks to renewable energy sources and the need grows to store and use them on demand. However, utility companies need to know the best way to operate those batteries to meet specific energy management goals. Sandia is helping by testing a large vanadium redox-flow battery at its Energy Storage Test Pad site and developing a system to evaluate and refine the calculations that control how the battery works.
Researchers have used the same test site at Sandia since 2012 to characterize how battery systems perform. Now they are moving beyond battery performance and reliability to study how energy storage control algorithms could affect both grid resiliency and applications, leading to significant cost savings. A control algorithm uses a set of rules that prompt an action or multiple actions to occur based on real-time data and measurements. The project will also study long-term battery capacity change, measure performance degradation over time, and assess control system cybersecurity.
“We are developing different control models at Sandia to look at how to best dispatch energy from storage systems — when, where, and how much,” engineer Ben Schenkman says. “Every battery vendor needs control with energy storage, so there are a lot of controls out there. We want to evaluate which controls work the best for specific energy management goals, like peak-shaving, transient stability, and energy shifting, and validate those models.”
Charles Hanley, senior manager of Sandia’s grid modernization programs, says the project will ease the way to a more-resilient national electric grid supported by battery storage.
“We envision a future electric grid with massively large amounts of battery storage, with systems that range across various physical sizes and applications,” Charles says. “Understanding how best to utilize these batteries safely and economically will add to the overall resilience of our electric grid. This installation is critical for us as we address this national challenge.”
To study how energy storage controls can impact resiliency, the research team will connect the battery — which can generate 250 kilowatts for up to four hours — to the microgrid at Sandia’s Distributed Energy Technologies Laboratory and evaluate how the battery performs when it is isolated from the grid. They are also assessing the economic impacts of various control models and how and when to use them.
We are looking at how the same battery that makes your grid more resilient during severe weather can also have a daily economic value by using various control methods and applications,” Ben says. “Severe weather can be a high-consequence event, but you won’t need your battery for resilience applications every day.”
Sandia will also test various control systems supplied by battery vendors to evaluate and recommend refinements, based on how they perform. “They can bring in their controls, and we can evaluate them and study how they work with the system,” Ben says. “We’ll look for flaws and opportunities for enhancements, and we’ll also be able to run an apples-to-apples type of comparison on controls.”
By Kristen Meub