As New Englanders celebrated Christmas Eve, the region’s power grid operator came closer to ordering rolling blackouts than it had in more than four years as several power plants failed to deliver on reserve capacity.

Wyman Station in Yarmouth Tux Turkel/Staff Writer

During that period, Wyman Station in Yarmouth, an oil-fired power plant that runs infrequently, was called into service to help keep electricity flowing in New England. The plant is operated by NextEra Energy and went online in 1978. It has a total capacity of 822 megawatts, the largest in Maine. It was among the generators that combined to burn an estimated 31 million gallons of oil during the period, according to the ISO.

ISO New England imposed penalties of roughly $39 million on power plant operators for failing to provide reserves during a confluence of factors including extreme cold in parts of North America.

“It was not the Christmas Eve that we expected,” Matthew Kakley, ISO spokesperson, said Monday.

The power grid operator had to dip into reserves as an Arctic blast swept across a large swath of the U.S. and Canada, necessitating controlled power outages elsewhere, while tens of thousands of New Englanders were in the dark after a powerful wind storm.

Part of the problem was that Quebec cut some of the electricity destined for the U.S. because of extreme cold in the Canadian province, Kakley said.

The region’s generating mix typically is dominated by natural gas-fired power plants, averaging 50%. On Christmas Eve, oil-fired plants including Wyman made up 29% of the total. Oil was followed by nuclear power, at 23%; natural gas, at 16%; Canadian imports at 15%; domestic hydro at 8% and other renewables, such as wind, at 8%.

A “capacity deficiency” declaration at 4:30 p.m. meant there were insufficient reserves, and some power plants responsible for bridging the gap either underperformed or were offline, he said.

The steps leading up to the decision were detailed in a report from the ISO called: “December 24, 2022, OP-4 Event and Capacity Scarcity Condition.”

OP-4 refers to the level of operating procedure put in place when there’s a capacity concern.

With the system maxed, and little safety net, the next step would have been to ask for voluntary conservation measures or rolling blackouts.

But the problem dissipated quickly with the deficiency declaration being lifted in less than three hours as consumer demand dropped during the evening hours, Kakley said.

The last time the situation was so dire was over Labor Day weekend in 2018, when $36 million in penalties were levied, he said.

Privacy rules prevented the power grid operator from publicly identifying the underperforming power plants and their owners, he said.

And while the grid operator also doesn’t publicize which plants are running, on Christmas Eve and Christmas Day, a plume of smoke was visible on Casco Bay from Wyman Station, which is located on the tip of Yarmouth’s Cousins Island. On Sunday and Monday, a barge resupplying the plant with fuel oil was seen docked at the terminal.

Power grid rules call for the financial penalties to be distributed among those power plant operators that did step up to meet demand, he said.

In the end, the Christmas Eve situation in New England was not as extreme as the situation in other parts of the country.

The supply of natural gas, a key energy source for power plants in New England, was not a factor, Kakley said. In fact, heating oil became more economical than gas-fired generation during the period, he said.

Staff Writer Tux Turkel contributed to this report.