solar battery storage

Companies are lining up to offer battery-storage options to Hawaii customers that own solar panel systems — a move regulators and clean-energy advocates are hailing as a way to help the state reach its 100 percent renewable energy goal.

The need for such energy-storing technology was sewn into different regulatory orders and utility proposals when the state Public Utilities Commission announced it would limit the number of new residential and commercial projects allowed to export solar energy to the grid, but continue to allow solar panel systems that stored excess energy in batteries. Clean-energy organizations and solar energy companies said batteries used with time-of-use rates could provide an incentive for homeowners to continue adopting rooftop solar panels, but the cost of such batteries is still out of reach for most.

“Battery storage is going to become important, especially as we move forward,” PUC Chairman Randy Iwase said. “Especially given the fact that the grid today is reaching near saturation.”

In October the PUC ended the net energy metering (NEM) program that credits solar panel owners for the excess energy their photovoltaic systems send to the grid. The PUC is replacing NEM with a program that gives new solar panel owners a slower return on their investments. New solar panel owners who choose to send their excess energy to the grid will be credited 15.07 cents per kilowatt-hour. This new program has a limit of approximately 4,000 homes.

After that limit is reached, customers still will be able to add solar panels to their houses but will not be able to send power to the grid.

The current program that credits solar owners for the excess energy they send to the grid will enable them to recoup their investment in six to eight years. A solar panel system connected to a battery has an eight- to 12-year payback period. A customer using a battery is eligible for a 30 percent federal tax credit if it is used with PV panels. There is no state tax credit for batteries.

“It’s not quite ready for prime time, essentially,” said Colin Yost, principal at RevoluSun.

The list of energy companies working to provide energy storage solutions includes San Jose, Calif.-based JuiceBox Energy; San Francisco-based Sunverge Energy; Pittsburgh-based Aquion Energy; Honolulu-based Blue Planet Energy; San Mateo, Calif.-based Tesla; and Honolulu-based E-Gear LLC.