Gov. David Ige, renewable-energy advocates and the electrical utility celebrated the installation of the first Tesla Motors Powerwall battery linked to a solar system in the state, saying it was an important “milestone” to get to Hawaii’s 100 percent renewable-energy goal.

More than 40 members of the energy community gathered Friday at the home of Anthony Aalto, chairman of the Sierra Club Oahu, on Wilhelmina Rise to view the blessing of the Sunrun BrightBox, a battery-connected solar system from San Francisco-based Sunrun Inc.

The company said the typical system with two Powerwalls and 28 panels would cost homeowners $40,000 without tax incentives and roughly $20,000 after the credits. Homeowners can lease the system with no down payment and pay Sunrun 19 cents a kilowatt-hour for 20 years. Hawaiian Electric Co. charged customers 22.6 cents a kilowatt-hour in April.

Ige said the combined solar and battery system on Aalto’s home was a pivotal step as the state works to achieve 100 percent of its energy generation from renewable resources by 2045.

“This is a key milestone to get us to 100 percent renewable,” Ige said at the event. “It’s all about storage and cost-effective storage.”

The installation comes seven months after the Public Utilities Commission ended a popular solar incentive program called net energy metering, which credited customers the full retail rate for the excess energy their systems send to the grid.

The PUC replaced NEM with two new programs. “Self-supply” typically involves rooftop solar with batteries and doesn’t allow the homeowner to export power to the grid. The owner can still draw power from the grid if needed. The other program, “grid-supply,” credits homeowners roughly 10 cents less than the retail rate for excess energy sent to the grid and has a cap equivalent to roughly 4,500 homes on Oahu.

Richard Wallsgrove, program director at Blue Planet Foundation, said the installation provides HECO the opportunity to begin to draft its plan to use batteries as a resource for the grid.

“This is the starting point for HECO to figure out how to use distributed batteries to get more renewable on the system,” Wallsgrove said.

HECO spokesman Peter Rosegg said the installation was a milestone, and as the utility begins to see more self-supply systems on the grid, it would look at how to use them as a resource.

“It’s a good first step,” Rosegg said. “We hope to see a lot more of these. It will lead to other possibilities, but it will take a volume of these systems before we get there.”

Solar industry leaders said it is important to create an incentive program for batteries because grid-supply might run out before self-supply takes off.

There are six self-supply applications waiting for approval on Oahu. There are seven waiting for approval on Maui.

“It’s still kind of expensive,” said Colin Yost, principal at RevoluSun. “Without incentives it will be a while.”

Two bills that would have provided incentives for batteries did not make it out of conference committee at the Legislature. The state currently offers a 35 percent tax credit for solar systems. There is also a 30 percent federal tax credit for solar systems. The state does not clearly define whether batteries are covered by the credit.

HB 2291 included a section that would make solar-powered batteries eligible for the state’s renewable-energy tax credit while decreasing the tax credit for new rooftop solar systems. Senate Bill 2738 would have appropriated $50 million for a battery rebate program. The money would come from a program put in place to help low-income residents pay for rooftop solar systems.

“I think it is important to have an incentive, especially for middle- and lower-class families so they’re able to save money as well as provide a benefit for all ratepayers,” said Rep. Chris Lee (D, Kailua-Lanikai-Waimanalo).

Aalto said he hopes his system will encourage others.

“My goal is to show people what we can do going forward to live more sustainably,” Aalto said.