Two years ago, AEP Ohio kicked off one of the largest community energy storage projects in the nation, funded in part by the U.S. Department of Energy.
The pilot, however, did not go very far.
“The initial battery implementations associated with the Community Energy Storage (CES) project did not perform to AEP and S&C’s stringent standards, which prompted redesign of the battery systems,” AEP said in a statement. “Unfortunately, those necessary improvements were not completed in time to resume the full-scale program before the December 2013 end date of the AEPOhio gridSMART Demonstration Project.”
AEP and S&C, which was the vendor for the pilot, declined to speak specifically about the project and the shortcomings of the batteries, although the two will continue to work together on a much smaller scale.
Small scale is exactly where community energy storage is at. It’s not only the scale of the batteries that are small (compared to megawatt, grid-level storage), but also the scale of utility uptake. “We haven’t seen any mass deployment,” said Mike Edmonds, vice president of strategic solutions for S&C. “It’s a very young market.” Instead, utilities are dipping their toes in the water by testing just a few units.
The project in AEP Ohio would have installed 80, 25 kilowatt-hour lithium-ion battery packs on one circuit next to distribution transformers in neighborhoods. By contrast, Duke Energy and Scottish and Southern Energy each have just a few.
One of the problems, according to Edmonds, is the size itself. Most utilities, especially those outside the U.S., are looking for something larger. S&C is developing a 250-kilowatt battery that will appeal to that market and can be used for many of the same functions as the smaller storage device, such as voltage smoothing for solar PV.
Another issue, said Edmonds, is the burgeoning battery management system (BMS) market. “At this stage, you can’t have a generic BMS,” he said. He noted that each battery manufacturer produced a product in a slightly different flavor and therefore need tailored management systems. While large battery makers like Samsung are working on the issue, so are startups like Toronto’s eCamion.
There also needs to be more development in platforms that can control devices individually and on a fleet level. Duke is using Alstom as a distributed energy manager as it tests storage options.
For utilities that do want the smaller 25-kilowatt units, S&C recommends six on one feeder. But for far more utilities, Edmonds thinks the 250-kilowatt unit will be more attractive, with all of the same benefits as the smaller units. But carmakers, for one, would love to see a robust market for used EV batteries. ABB is working with GM and Nissan to test used EV batteries as grid storage devices.
Solar PV disruption is driving the market, but Edmonds estimates it will still be two to four years before utilities are deploying community energy, no matter what the size. But when a lot of PV comes on feeders, Edmonds said the cost of batteries starts to be more attractive compared to upgrading the grid.
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