The Northern Pass Transmission project ran into an obstacle Thursday when New Hampshire regulators rejected a permit for construction.

A panel appointed by the Massachusetts government selected Northern Pass just last week from among 46 proposals to bring clean energy to the state. The developers, Eversource and Hydro-Quebec, expressed confidence at the time that the outstanding permit would be granted and construction could begin this spring.

The unanimous vote by the New Hampshire Site Evaluation Committee (SEC), citing impacts on local tourism and business, proves that confidence was misplaced.

Eversource responded that it was "shocked and outraged," according to the Boston Globe, and vowed to appeal the decision. The company maintains that the body of evidence supports its application.

The $1.6 billion Northern Pass would entail a 192-mile, 1,092-megawatt transmission line to carry hydropower electricity from Quebec through New Hampshire, underground through the White Mountains and out to Massachusetts on the other side. The developers insist that more than 80 percent of the line would slip into existing right of ways or be buried underground to avoid disruption.

That hasn't stopped clean energy advocates and conservationists alike from opposing the project. Greentech Media recently examined the multi-sided controversy in this article.

One major concern, that Massachusetts was putting all its eggs in one basket by choosing to procure so much clean energy from a single project, has been borne out by the New Hampshire ruling.

The deciding committee in Massachusetts, which includes the state's utilities (including Eversource itself) and the Department of Energy Resources, will have to explain why it didn't consider the lack of a New Hampshire construction permit to be an obstacle. Numerous other proposals avoided New Hampshire altogether.

The rapid-fire rejection by the SEC makes the situation all the more embarrassing for Gov. Charlie Baker's administration, which spent last week touting how excited it was about the choice of Northern Pass.

"We had a lot of good options, and this is the one that rose to the top," DOER Commissioner Judith Judson said of the project just last week.

This saga isn't over yet. It's hard to see how Eversource could flip a unanimous commission on appeal, but eventually it could go to the state Supreme Court to overturn the SEC's decision. In the meantime, it won't be able to start building on the hasty production schedule it had proposed in order to deliver power by the close of 2020.

It's not yet clear what options Massachusetts has to pursue while the legal battles next door sort themselves out. If the state waits for the final decision on Northern Pass, it almost certainly won't get the power as originally planned, which could jeopardize its legislative commitments to reducing carbon emissions.

The planned 2019 retirement of the Pilgrim nuclear plant will only exacerbate the need for more clean electricity.

Meanwhile, the 45 other proposals are sitting on a shelf somewhere. Some would produce renewable energy locally; some would bring it from Canada via other routes with less grassroots opposition.

Massachusetts will have to decide how long to wait for Northern Pass to pull through, or whether it can change plans at this stage of the process.