So if it’s not the solar program, then what is causing utility bills to rise? One of the main forces driving electricity prices is the cost of energy supply in New England, more than half of which comes from natural gas–fired power plants. Volatility in the natural gas market, therefore, translates directly into higher electricity rates for consumers. Prices spiked in 2022 and 2023, for example, as the war in Ukraine pushed the cost of natural gas up worldwide. This year, energy supply accounts for 39% of a typical Maine household’s monthly bill — roughly nine times the cost of net energy billing — according to ReVision’s numbers.

“Solar isn’t the problem. Fossil-fuel volatility really is,” Bourgoine said.

The other major contributor is rising transmission costs, which on average make up 51% of electricity bills, up from 37% in the second half of 2023.

There are some commercial cases in which the cost for net energy billing does have an outsized impact on energy bills, supporters of the incentive agree. Commercial power customers are charged a fixed rate based on the specific rate classification their business falls under. This system means some businesses end up with a much larger percentage of their bill paying for net energy billing.

At last week’s hearing, Sen. Stewart testified that potato processor Penobscot McCrum will pay close to $700,000 in public-policy charges this year. Roughly 55% of this charge reflects the costs of net energy billing, according to utility Versant.

Supporters of net energy billing agree that situations such as these are unfair and unsustainable, and a docket is already underway with the state Public Utilities Commission to address that specific issue without repealing the entire net energy billing program, Donoghue said.

“There is a certain amount of customers that, we agree, should be complaining,” she said.

Net energy billing also provides benefits that are hard to see but which offset the costs, supporters said. In 2023, the program cost ratepayers $130 million but delivered $160 million in benefits to the state, according to an independent analysis prepared for the Public Utilities Commission. By adding solar power to the grid, the program helps suppress wholesale electricity prices, for example, and it improves reliability because there cannot be a shortage of ​“fuel” for solar generation.

More solar generation in the state means more Maine households are getting power produced in or near their communities, lowering the strain on the transmission and distribution systems — and the associated costs. Solar developers also pay for any infrastructure upgrades needed to accommodate their projects.

“Those are investments that utilities don’t have to put on ratepayers,” said Jack Shapiro, climate and clean energy director for the Natural Resources Council of Maine.

Furthermore, eliminating net energy billing would have its own financial consequences for the roughly 110,000 customers enrolled in the program. The abrupt end of all net energy billing would leave these participants — including residents, businesses, and schools – without promised and planned-for savings, Shapiro said.

Opponents in the Legislature have passed three rounds of rollbacks to the program. Now they want to go even further.

“If [these bills] were passed, they would actually have some truly disastrous consequences for a lot of people and schools and municipalities,” Shapiro said.