Nearly nine months after energizing his 28 solar panels and two batteries, Anthony Aalto is still championing his choice to be the first “self-supply” solar program participant in Hawaii — with his $35 electric bill in hand.

Aalto, chairman of the Sierra Club Oahu Group, forfeited his spot for a popular solar incentive called net energy metering (NEM) to be the first to install a Hawaiian Electric Co.-approved self-supply system.

“The intention is I supply all of my own needs but in the event of a disaster, a battery goes down or whatever, I’m still connected to the grid,” Aalto said. “I can still pull power off the grid. In fact, I still do.”

The self-supply program is arguably the least attractive solar incentive program the state has offered, prohibiting solar owners from exporting energy into the grid while other programs credited solar system owners for that energy. Owners are also encouraged to buy batteries, adding to the price of their system.

Grid supply, which credits 15 cents for excess energy sent to the grid, and self-supply were the programs that state regulators used to replace NEM in October 2015. Both were regarded as a lower value to homeowners compared with NEM, which credited the full retail rate for exported energy. Through NEM, most solar owners reduced their electric bills to $17, with a projected payback for the cost of installation at roughly five years.

Aalto turned on his self-supply system, which consisted of two Tesla Powerwalls for his 28 panels, in May. He was the only owner on the self-supply system until the grid-supply program met the cap placed on it by the state.

By December, HECO had received more than 350 applications for “self-supply” rooftop systems.

“The only drawback with self-supply is that you have the additional cost of the batteries,” Aalto said. “The time it takes to pay the cost of the investment is a bit longer because the investment is a bit bigger. … After that you’re free and clear and everything is just gravy.”

But even with self-supply, Aalto said, he was saving money from day one. “Going green does actually save you a lot of money,” Aalto said.

Without any lifestyle changes, Aalto said, he was paying an electric bill of $35: He pays HECO $25 a month to stay connected to the grid and $10 for the small amount of electricity he still pulls from it.

“I want to close that,” he said, working to do that with some minor lifestyle changes.

“Instead of running the dishwasher at night I run in the daytime,” he said. “Instead of doing our laundry at night I do it in the daytime, and I charge the EV in the daytime whenever I can. The extent that I can, I charge it in the daytime.”

Aalto said the system reduced his electric bill from an average of $160. Aalto said he is paying off his $18,250 system over the next 18 months.

His guinea pig position resulted in higher savings than most self-supply owners would receive, as his two Tesla Powerwall Batteries, priced at about $6,000, were free donations when he did his installation.

The net cost if one were to take out a home equity loan for a self-supply system like Aalto’s ranges from $115 a month with a 3.5 percent interest rate and $163 with a 7.5 percent interest rate over a 10-year period. That includes Aalto’s monthly savings of $125 compared with his original electricity bill.

Because of the decreasing prices for storage, the payback period can be less than eight years, said Colin Yost, principal at Revolu­Sun.

Aalto also bought a used Nissan Leaf for $7,000 at the same time he purchased the solar and battery system. The electric vehicle added to Aalto savings by helping him to save the money he spent on gasoline.

If Aalto had paid for his batteries, the upfront cost to power his home and car with renewable energy would have been $31,250.

Aalto’s solar energy system was installed on his remodeled home, which he said he custom-built to be environmentally friendly.

“I wanted to build a house that people would see that … you don’t have to suffer,” he said. “It doesn’t have to be ugly.”

The old house was deconstructed by nonprofit Re-use Hawaii, which cost Aalto $12,000 to $14,000, he said. Aalto said it would have cost $7,000 or $8,000 to demolish.

“It was something like $5,000 more than just letting a bulldozer do its thing,” Aalto said.

The materials that Re-use Hawaii was able to recover had an assessed value of $39,000, Aalto said.

“The way the system works you just donate stuff to Re-use Hawaii, they’re a nonprofit,” Aalto said. “That becomes a tax-deductible donation. You can use that deduction over the years. If you don’t have a high enough income to use that all in one year, that is not a problem, you can use it over several years.”

The home also has light-emitting diode (LED) light fixtures, kitchen cabinets made with reused materials. and infrastructure for gray water to be used for toilets.