SOUTH PORTLAND — The Maine Green Power program is seeking residents and business owners in the city who want to help subsidize the expansion of renewable energy generation in the state.

The program kicked off its South Portland Green Power District Challenge in July, mailing out fliers that aimed to drum up at least 100 residential and 10 business participants by the end of the month.

The challenge has been extended through August after about 60 residents and 10 businesses signed up, said Kathleen Nickerson of 3Degrees Inc., the company that manages the program for the Maine Public Utilities Commission.

Participants in the Maine Green Power program buy renewable energy certificates through their electricity bills from Central Maine Power Co. or Emera Maine. The money is used to support solar, wind, hydro, tidal, biomass and other renewable energy facilities in Maine that deliver electricity to the regional power system.

“The goal is to build a renewable energy market in Maine and support the development of new renewable energy generators,” Nickerson said.

The program targeted South Portland as a potential Green Power District after a market study recognized residents’ pre-existing support for sustainability, said Harry Lanphear, the PUC’s administrative director.

In recent years, the city has funded or approved a sustainability department, a municipal solar array, pesticide and plastic foam food container bans and a single-use shopping bag fee, among other climate-action efforts. Similar Green Power Districts have been established in Brunswick and Portland’s Parkside neighborhood.

Participants in the Maine Green Power program wind up paying more for their electricity and there’s no guarantee that the power they receive comes from renewable sources. However, the program ensures that a certain amount of electricity generated by renewable sources in Maine will be delivered to Maine consumers.

“We’re getting more renewable energy onto the grid,” Nickerson said.

Depending on the price of Maine-based renewable energy certificates, the program may purchase its renewable energy supply from sources outside the state, according to the flier sent the South Portland residents.

In June, Gov. Janet Mills, a Democrat, signed legislation that aims to double the percentage of renewable power sold in the state to 80 percent by 2030, and 100 percent by 2050.

In 2018, about 75 percent of Maine’s net electricity generation came from renewable energy resources, the U.S. Energy Information Administration reports. Thirty-one percent came from hydroelectric facilities, 22 percent from biomass (mainly wood products), 21 percent from wind and a small amount from solar. The remaining 25 percent came from fossil fuels, mostly natural gas.

Maine Green Power was established by legislation passed in 2009. Following a competitive bidding process, the Maine PUC selected 3Degrees Inc., a San Francisco-based company, to manage and market the program.

Since its launch in 2013, the program has raised just over $1 million to support renewable energy development in Maine, based on annual reports filed by 3Degrees. Facilities supported by the program include Fogg Hill Solar in Stockton Springs, Maine Tidal Energy in Eastport and Rollins Wind in Lincoln, the program flier says.

In that time, enrollment has grown from about 800 participants in 2013, when the program collected $21,540 for the year, to 4,400 participants today, including about 200 businesses, Nickerson said.

The program purchased 1,436 renewable energy certificates associated with participants’ electricity use in 2013, annual reports show. Four years later, in 2017, it purchased 15,249 certificates. 3Degrees hasn’t filed its report for Maine Green Energy’s activities in 2018. Nickerson said the program collected about $304,000 last year.

About 80 percent of the $1 million raised in the last six years has gone to renewable power generators to pay for facility maintenance and expansion, and 20 percent went to 3Degrees to cover administrative and marketing costs, Nickerson said.

Annual reports say before March 2016, 3Degrees was required to spend at least 50 percent of revenue from program participants on renewable energy certificates. After March 2016, 3Degrees used at least $5.50 per certificate purchased by participants to buy renewable energy.

Maine Green Power allows participants to contribute at levels that suit their budget or business model. A half block (250 kilowatt-hours) costs $4.95 per month; one block (500 kilowatt-hours – the monthly average for a Maine household) costs $8.95 per month; two blocks (1,000 kilowatt-hours) cost $17.90 per month.

Ten blocks (5,000 kilowatt-hours) or more can be purchased at a reduced monthly rate of $6.45 per block. Businesses that choose this option will be contacted by a Maine Green Power representative within five business days to discuss the appropriate enrollment level and recognition benefits, according to the PUC website.