Regulators in the state of New Hampshire have rejected a major electricity project being piloted by Quebec's hydro utility and its American partner, Eversource.

Members of New Hampshire's Site Evaluation Committee unanimously denied an application for the Northern Pass project today.

The project had been approved by the state of Massachusetts at the end of January but needed the green light from New Hampshire as well.

Northern Pass proposed to bring up to 9.45 terawatt hours of electricity per year from Quebec's hydroelectric plants to

Massachusetts. It was to be the biggest export contract in Hydro-Québec's history.

The project was estimated to generate up to $500 million in annual revenues for Hydro-Québec.

The New Hampshire Union Leader reports the seven members of the evaluation committee said the project's promoters couldn't demonstrate the proposed energy transport lines wouldn't interfere with the region's orderly development.

'Not the end of the process,' Hydro says

Hydro-Québec said it was disappointed by the news but that "this is not the end of the process."

"We are looking into, 'Can we provide them with additional information? Can Eversource answer their questions?' Secondly, there is also an appeal process in place for such instances. So Eversource is looking at these

options and trying to find out what our options are," Hydro-Québec spokesperson Serge Abergel told CBC's Homerun.

Abergel added that Hydro-Québec also submitted two other projects as a back-up, and those are still on the table.

"We submitted Plan A, but we also have a Plan B and C.… So if this one weren't to work, we also have other projects that will work, and they're very competitive."

Meanwhile, Hydro-Québec's American partner in the project, Eversource, issued a strongly worded statement Thursday afternoon.

"We are shocked and outraged by today's SEC outcome. The process failed to comply with New Hampshire law and did not reflect the substantial evidence on the record," it said.

"We will be seeking reconsideration of the SEC's decision, as well as reviewing all options for moving this critical clean energy project forward."