Hawaii Looks Behind the Meter for Solutions to Meet Emergency Needs

What happens in Hawaii has been described as a postcard from the future. The latest message from Hawaii is that coal will no longer be used to produce electricity. Instead, solar paired with storage will fill the gap. And a large portion of that combined clean energy resource could be located behind-the-meter.

In an innovative proposal, a coalition of solar parties have responded to a “call to action” by the Hawaii Public Utilities Commission’s with a proposal to quickly build 50 megawatts of behind-the-meter resources to meet a gap brought on by the impending closure of a 203 megawatt coal power plant on the island of Oahu by September 2022. The solar coalition, which calls itself the DER Parties, has proposed to leverage a concept called “Bring Your Own Device (BYOD)” to enable consumers to provide necessary services from their devices to the local electric utility, in this case the Hawaii Electric Company (HECO). The devices in the BYOD portfolio could be rooftop solar, battery storage or load control like smart thermostats, which would be activated during times of grid need.

The closure of the Oahu coal plant has triggered a two to three year shortfall in power generation needed to meet peak needs while utility scale solar plus storage power plants are being built. To bridge this multi-year gap the Hawaii Commission is proposing the creation of a new “Emergency Demand Response” program. The challenge facing Hawaii’s regulators is the need to act immediately while recognizing that the utility does not yet have the tools to control resources that are located behind customers’ meters.

To allow HECO the necessary time to install and debug a Distributed Energy Resources Management System (DERMS), the DER Parties have proposed three linked programs that could be implemented through amendments (riders) to existing base tariffs.

The first program, which the DER Parties call Scheduled Dispatch, would add battery storage to existing solar systems. Customers would receive a rebate from HECO sufficient to cover most of the up-front cost of a battery. The customer, in return, would agree to provide services to the utility for a 10 year period. For the first two years the batteries would charge during the day and discharge over a specified two-hour period during the system peak, from 5 to 10 pm.

After the first two years, customers would be given additional options for how their batteries could be used to meet grid needs. One option, available after the first two years of battery operation, would be for the customer to specify and commit to a schedule for load reductions over the five hour peak period. A second option, available once HECO has its DERMS platform up and running, would be to let HECO remotely control the charging or discharging of batteries during emergency conditions, in addition to regularly scheduled load reductions. These more advanced types of grid service would also be offered to customers who want to install a new solar plus storage system.

The DER Parties’ proposals for rebates and compensation under the new programs were based on Vote Solar’s modeling using HECO’s RESOLVE capacity planning model. The rebates and compensation for services will be considered by the Hawaii Commission and other parties over the next several months.

Vote Solar helped the DER Parties gain access to the RESOLVE model and through its use increased understanding of the value of the services that DERs could provide to the grid. The DER Parties acknowledged that Vote Solar’s modeling work revealed new opportunities for owners of DERs to improve the operation of the grid over the longer term.

A decision on the Emergency Demand Response program by the Hawaii Public Utilities Commission is expected within the next several months.