The future of Massachusetts' solar industry is in doubt after a bill to increase the clean energy's availability on the power grid stalled in the Legislature at the end of this year's formal sessions.

The House and Senate on Wednesday night couldn't come to an agreement on how much solar power to allow on the grid and how much to reimburse the people generating it.

Utility companies are concerned that since clean solar power is more expensive to produce than traditional, more pollution-heavy sources, it'll force them to pass on higher prices to their ratepayers.

But those from the solar industry say that not only is solar crucial to meeting the state's clean energy goals, without higher earnings and commitments for solar in Massachusetts, they'll take their companies — and jobs — to other states.

"This will force all developers who are in this region to focus on other markets because these markets are not viable at this point," NextAmp CEO Zaid Ashai told WGBH News.

After the House passed a bill roundly panned by solar advocates, a six-member panel from both chambers rushed to reconcile the differing plans. The talks did not result in a merged bill, however, as the House adjourned its last session of the year before the conference committee could resolve the issue.

Rep. Tom Golden (D-Lowell), the House's lead negotiator with the Senate on the solar cap issue, told WGBH News the chambers are close enough to a deal that the bill could move forward in informal session before the resumption of formal meetings next year.

By failing to finish work on the bill when the Legislature was in formal session, the conferees now have to hash out a plan that can pass both chambers in informal session. In these sparsely-attended informal sessions, any member can for any reason put a stop to legislation proceeding to Gov. Charlie Baker's desk.

Golden and his Senate counterpart, Sen. Ben Downing, need to balance the desires of passionate environmentalists and the energized solar industry against the concerns of the electrical providers and lawmakers concerned with increasing costs for clean energy.

"People want this to be affordable," Golden said. "They want to have a green community. They want to watch out for the ratepayer. Green energy is extremely important, but I think we need to watch for the ratepayer and what is going on here, and that is probably the most difficult part here."

Downing didn't want to put any kind of timeframe on when the bill might get done, but told reporters after the House left for the year Wednesday that the conference committee was "still working and still talking."

But the clock is ticking on many solar projects that rely on federal grants to attract investments. Those grant applications have deadlines, and without assurances that the state will allow more solar generation on the grid, the grants and projects are threatened.

"We want to make sure we take advantage of the federal investment tax credit, I know that's a goal that both sides have, and every day that we don't, that's a missed opportunity," Downing said.