WARWICK, R.I. — Delays keep piling up for the fossil fuel power plant proposed for Burrillville, as the Energy Facility Siting Board (EFSB) has agreed to postpone the application process another 90 days.

The latest delay came after a four-hour hearing on Nov. 27 to address four motions from opponents to amend or dismiss the $1 billion project.

The Conservation Law Foundation (CLF) was granted its request for updated reviews from the the Office of Statewide Planning and the Office of Energy Resources. The motion was submitted by CLF after Invenergy Thermal Development revealed that one of the power plant’s two turbines was shut out of an annual electricity auction. CLF and the town of Burriillville criticized Invenergy for waiting five weeks to divulge the decision by the operator of the regional power grid, ISO New England, to preclude half of the power generation from the yet-to-built power plant.

Invenergy’s failure to sell its power into the grid likely delays the completion date for the nearly 1,000-megawatt project by one year, to at least 2021. Construction can only begin if the application is approved by the EFSB. With the 90-day delay, a decision on the application isn’t likely until June.

Jerry Elmer, senior attorney for CLF, noted that the proposed Clear River Energy Center also faces additional hurdles, such as getting a buyer for its power. The decision by ISO New England marks the third year that Invenergy has been unable to sell its electric capacity. Elmer noted that the ruling likely hurts financing for the natural gas/diesel project and even allows ISO New England to pull back its agreement to buy electricity from the turbine it already promised to buy.

Invenergy insists that there will be ample demand for electricity from both turbines once older New England power plants retire. Attorney Alan Shoer said Chicago-based Invenergy funds many large energy projects.

“There is no question they have the ability to finance the project,” he said.

Either way, the EFSB granted time for more analysis of the power-plant proposal.

The EFSB rejected a request by the Narragansett Indian Tribal Council to serve as an intervenor in the application review process. The Narragansett Indian Tribe argued that the decision to sell water to Invenergy was made illegally by tribal leaders without consent from the council. However, EFSB chairwoman Margaret Curran said she had a signed agreement from tribal leaders and didn’t wish to get involved with tribal politics.

“I think we should take that (agreement) at face value and avoid getting involved with the tribe’s internal conflict,” she said.

The EFSB didn’t act on a motion to hold a public hearing on the water agreement between the Narragansett Indian Tribe and Invenergy, as hearings are already planned for Dec. 5 and 6 in Charlestown and Burrillville, respectively.

The EFSB denied the town of Burrillville’s request to suspend or dismiss the application altogether. The town’s attorney, Michael McElroy, argued that Invenergy failed on several occasions to provide information and failed to meet deadlines.

“The town has had to fight for everything it has been looking for,” McElroy said. “And Invenergy has fought at every turn.”

The EFSB, however, agreed with Invenergy that many of the missteps and delays were addressed in previous motions or would be debated in the final stage of hearings. Those hearings were expected to start Dec. 8 but will likely begin in March.