Hawaiian Electric Co. customers can pay a one-time fee of at least $2,000 to participate in a renewable-energy project, such as a solar farm, and receive a discount on their monthly electrical bills, under a new program mandated by the state.

The program gives those who do not have space on their roofs for a solar system a way to lower their electrical bill by investing in renewable energy.

“The goal is that all customers share in the benefits of low-cost power,” HECO said in a news release Thursday, announcing its Community-Based Renewable Energy program.

A new state law mandated that electric utilities come up with a plan that would allow residents to participate in owning a renewable-energy project even if they can’t install one where they live. The program is aimed at those who rent or live in condos, apartments or shaded areas. The deadline for the plan was Thursday, and it must be approved by the Public Utilities Commission before it takes effect.

In exchange for the one-time minimum payment of $2,071, a ratepayer gets an interest for 20 years in the electricity generated by a renewable project. Participants must hold that interest for a minimum of one year, after which it can be sold or transferred to another ratepayer.

Participants get a discount on their electric bill. The value of the discount would vary depending on which renewable-energy project a customer has bought into and how much of an initial investment the customer makes.

For an initial investment of $2,071 in a smaller project, the customer could get a discount of 12.33 cents per kilowatt-hour on his or her bill, HECO said. For the typical household that uses 500 kilowatt-hours per month, that means a $61.65 reduction in the monthly electrical bill. It would take a typical ratepayer less than three years to earn back the initial $2,071 investment. Customers could invest more to get a larger reduction on their bills.

The ratepayer does not get a federal tax credit for the investment in renewable energy, as do homeowners who pay for rooftop solar. The 30 percent federal tax credit would go to the developer of the project. It was unclear Thursday whether a customer could get the 35 percent state tax credit.

HECO said up to 8,540 residents of Oahu, Maui County and Hawaii island could participate in the program. Participants must select a renewable-energy project on their island from a list approved by HECO.

HECO wants to cap the community renewable projects at 32 megawatts.

Blue Planet Foundation, a clean-energy organization based in Hawaii, said the 32-megawatt cap for the whole state is too low.

“This is around 10 percent of the rooftop solar capacity that has already been installed over the past few years,” said Blue Planet Foundation in a news release.

Depending on PUC approval, HECO said it plans to begin selecting developers to build community solar projects in 2016.

“Expanding options is part of our effort to deliver value for our customers,” said Shelee Kimura, HECO vice president for corporate planning and business development. “Encouraging more customer participation in renewable energy supports our vision to integrate more low-cost renewables that benefit all of our customers and to lower customer bills by 20 percent by 2030 as we work to achieve 100 percent renewable energy by 2045.”