Dive Brief:

• EnSync Energy Systems on Wednesday signed a 20-year power purchase agreement for a solar-plus-storage project at a housing complex in Hawaii that will allow the residents to share power.

• The PPA is with Michaels Development Company, which is developing the Keahumoa Place affordable housing project in Oahu, expected to be completed in 2019.

• EnSync says residents of the housing complex will be able to store and share power from the 750 kW, 500 kWh solar-storage installation, making the facility more efficient and an addition to grid stability rather than a liability.

Dive Insight:

Adding energy storage to solar power is a growing phenomenon, but EnSync has added a new twist. The company plans to install solar panels on the canopies over the parking spaces of the 320 units of the housing development.

Not all the units will be equipped with energy storage capability. Those details are still being worked out, Ted Peck, CEO of EnSync’s Hawaiian subsidiary Holu Energy, told Utility Dive.

The solar and storage equipment will be connected by EnSync’s True Peer-to-Peer DC-Link technology that will allow the energy of the solar-storage system to be shared.

When a residential unit generates more solar power than it needs, it will charge a battery. When the battery reaches full capacity, the excess energy can then be used to supply units in the housing complex with higher demand or to supply common areas in the housing complex. Excess energy could also be exported to the grid for sale to Hawaiian Electric Co. (HECO) under the state’s customer grid supply rules. “That will depend on the tariffs we get” from HECO, Peck said.

When Hawaii rescinded its net metering program, it created two classes of solar customers with different tariff structures: customer self-supply and customer grid-supply.

Peck said that without the DC connect technology, the amount of load risk is significant, which would make it difficult to craft a viable PPA. EnSync’s PPA with Michaels aims to provide savings compared with HECO’s rates, but there are risks.

“Every load profile is wrong,” Peck said, because it is based on the past and has to apply to the future. Peck said he is still fine-tuning the engineering of the Keahumoa Place project, but being able to control the load with storage and by shifting the solar power helps. It increases the efficiency and lowers electricity costs for the entire network, Peck said.

Having a solar-storage system with a more predictable and manageable load adds to the stability of the grid, according to Peck, rather than injecting an intermittent resource into the grid. “That is a new thing,” he said. It is creating efficiencies that make clean energy affordable, and it is “providing value to its neighbors,” HECO included, Peck said.