Energy Storage, Solar Plus Storage, Demand Response, Sustainability, Virtual Power Plant (VPP)
1MW Virtual Power Plant
Hawaiian Electric (HECO) provides electricity to 95% of Hawaii’s residents on Oahu, Maui, Molokai, Lanai and Hawaii Island. The utility has strong clean energy support from its stakeholders and policymakers but limited land on which to build larger renewables projects.
In 2015, Hawaii became the first U.S. state with a legislative goal of 100% renewable energy. Given the utility’s land constraints, customer-sited renewables and battery storage became crucial to the state’s clean energy future.
Stem was the utility’s key partner in designing and implementing its first energy storage pilot, which was among the first of its kind in the U.S. With the support of a $1M federal grant, Stem and HECO successfully deployed a 1MW “virtual power plant” (VPP) on Oahu across 29 customer sites.
While solar panels were extremely popular with homes and businesses, they caused problems for HECO’s grid. Slowing installations to address those issues hurt the utility’s public image. With the importance of distributed energy resources (DERs) and the challenge of integrating them becoming clear, HECO wanted to capitalize on battery storage opportunities with minimal deployment challenges.
Stem and HECO worked together closely to develop program rules, enrollment strategies and incentives, and then jointly recruited customers: a diverse mix of Oahu’s hotels, schools, tourism spots and other businesses. Stem engineers also developed the VPP’s software platform and trained HECO staff on its use, joining grid operators in the control room to ensure a successful deployment.
The Stem VPP far outperformed the utility’s other demand response assets, routinely delivering 98-100% of expected capacity. And Stem’s software provided total visibility into the VPP network, which other demand response (DR) resources lacked. Deploying the successful pilot and hearing directly from customers about their priorities and needs were instrumental in helping HECO design the industry-leading grid services programs it offers today.