The Hawaiian Electric Co. (HECO) and technology service company Stem Inc. have successfully tested nearly 1 MW of energy storage systems at 29 commercial sites on Oahu, the companies said on January 30.
The novel pilot project, which sought “the ability to connect many customers’ energy storage with the utility,” comprises an energy storage “fleet” of different sizes that is installed at small businesses and local institutions, along with Stem’s predictive, cloud-based PowerScope software to help the businesses predict when their electric use will peak (Figure 6). Stem synchronizes the PowerScope information with data from HECO’s renewable generation monitoring and forecasting so the utility can schedule stored power at the varied customer sites for added stability during times of solar variability or peak demand.
The “virtual power plant,” is providing better real-time grid operations, HECO added. “These customer-sited solutions are an important piece of Hawaiian Electric’s strategy,” said Dora Nakafuji, HECO’s director of renewable energy planning. “This shows we can scale behind-the-meter energy storage to create a more stable and efficient grid as we provide customers with higher levels of renewable energy to reduce fossil fuel use and greenhouse gas emissions.” Stem, which said it pioneered the subscription-based “storage-as-a-service model,” said interest is poised to grow. The company has secured more than $350 million in project financing from partners that include Generate Capital, Starwood Energy Group, and Clean Feet Investors.
The project is also supported by Hawaii-based startup funding company Energy Excelerator and the Department of Energy’s Sustainable and Holistic Integration of Energy Storage and Solar Photovoltaic initiative.
—Sonal Patel is a POWER associate editor.