Why it’s hard for Mass. power plants to stop using oil

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A passersby walked through the snow near the Old State House.Keith Bedford

If you think today's weather is bad, just wait for the weekend.

The winds and snow drifts may be more inconvenient than the frigid air that's due to blast us on Saturday. But this extended spell of Arctic temps could pose an unusual challenge for the power plant industry.

With natural gas in high demand for heating, oil has emerged as the leading source of electricity in New England. Nearly one-third of our power is coming from oil-fired plants these days, versus practically zero on a normal day. Meanwhile, only one-fourth is from natural gas, compared to roughly half.

Many oil plants are running around the clock. Grid operator ISO New England says some are already running low on fuel. ISO gave no indication to worry about this weekend -- as long as the bad weather doesn't disrupt barge and truck deliveries. Some generators also are getting concerned about exceeding the state's strict emissions limits. But the Baker administration is prepared to temporarily waive those limits, if needed, to keep the lights on.

The energy market craziness is reviving the debate about whether more pipeline capacity should be built to tap into the vast reservoirs of gas a couple states to the west. Environmentalists see such projects as wasteful, expensive solutions to cope with unusually cold days; they say the region will rely more heavily on hydropower, solar and offshore wind within several years, anyway.

But oil generally remains a pricey and dirty way to generate electricity. This cold snap gives the region's utilities and their big industrial customers one more reason to complain about being at the wrong end of the pipeline.

Jon Chesto is a Globe reporter. Reach him at [e-mail] and follow him on Twitter @jonchesto.