Energy Musings - May 28, 2026
The recent heat wave that covered the U.S. Northeast created a serious electricity supply challenge for ISO-NE, the region's grid operator. It was forced to burn oil, as gas pipelines were full.
New England Grid Resorts To Oil To Avoid Crashing
A heat wave hit the East Coast last week. A Copilot search produced the following weather commentary from Accuweather.com.
“The East Coast is experiencing an unusually intense early-season heat wave, with New York City and surrounding regions expected to see temperatures approaching 100°F around May 19–20, 2026, accompanied by high humidity that could push heat index values into the triple digits. This surge is affecting much of the eastern United States, including major metropolitan areas such as Boston, Philadelphia, and the Tri-State region.”
The heat wave arrived at the same time the North American Electric Reliability Corporation (NERC) produced its final 2026 Summer Reliability Assessment for the continent’s electricity grids. The following chart summarizes NERC’s view of the upcoming summer and which electricity grids will be under the most stress. The assessment is based on modeling forecasted weather against generating resources, power imports, and projections of maintenance and forced outages to generating capacity.
The report highlighted three regional grids with an elevated risk of being unable to meet their projected power needs. The New England regional grid was one of the three. The map also showed a fourth problem, an area of the Texas power grid that may experience localized power constraints this summer.
ISO-NE was one of the grids identified as being at risk this summer.
Little did NERC know that the publication of its assessment would coincide with an early-summer heat wave before the start of summer. In the case of the Independent System Operator – New England (ISO-NE), which manages the region’s electricity grid, the heat wave produced a higher peak load than forecast. Still, fortunately, grid resources were greater too.
The real story of the heat wave for ISO-NE was their need to resort to oil-fired power plants for electricity because the region’s natural gas pipelines were full. The available gas was insufficient for generating electricity to meet the grid’s needs.
While the heat wave began on Tuesday, May 19, it wasn’t until Wednesday morning that ISO-NE declared “abnormal conditions,” which alerted power plant operators to suspend maintenance that would reduce output. However, ISO-NE was forced to burn oil to generate 700 megawatts (MW) of electricity early Wednesday morning.
By examining the seven-day forecasts generated by ISO-NE beginning on Monday, May 17, we can see the impact of the warning to generators and how that helped avoid a problem for the grid’s customers.
The May 17 forecast, including May 19 and May 20, called for high temperatures of 89ºF and 87ºF in Boston, respectively. By the May 19 forecast, those temperatures were expected to be 92ºF and 88ºF.
The expected system generating outages for maintenance and repair were projected in the May 17 forecast to be 9,299 MW and 9,481 MW for May 19 and May 20, respectively. In the May 19 forecast, those numbers were reduced to 7,913 MW and 8,366 MW. The postponement of maintenance work added 1,386 MW and 1,115 MW of generating capacity available on May 19 and May 20, respectively.
The available grid resources were also boosted by additional power imports of 50 MW and 125 MW on May 19 and May 20, respectively. While not particularly large numbers, ISO-NE was receiving over 3,000 MW of imported power, which boosted the total grid output plus imports to 23,281 MW and 23,028 MW on the two days. The net result of these adjustments was that ISO-NE’s grid resources increased by about 900 MW and 725 MW on May 19 and May 20, helping to avoid a disaster, as peak demand was 1,200 MW higher on May 19 than forecasted earlier.
The May 20 seven-day forecast showed that the measures being undertaken for May 19 and May 20 were increased to ease the continuing heat wave. Maintenance work was reduced by another 400 MW for May 20 from the May 19 forecast, while power imports remained elevated at the May 19 forecast level. These adjustments were beneficial, as peak demand was 18,330 MW, up 580 MW from earlier forecasts and 620 MW below the peak demand for May 19.
While these are daily numbers that reflect forecasts for the grid, the test of any electricity grid is its minute-by-minute performance during the day. Media reports highlighted the need for the grid to burn oil, but didn’t specify what oil. One report noted that ISO-NE’s website did not specify what oil was burned, so it listed the possibilities as “crude oil, residual fuel, or another refined product.”
Clearly, the writers are unfamiliar with oil and are unable to do an Internet search. We are sure it wasn’t crude oil, as there are no refineries in New England to process such oil, so where would it come from? It was most likely heating oil, the primary backup fuel for electricity generation in New England. It is readily available as a large share of homes burn oil for winter heat. With the winter season over, heating oil would have been readily available. It is also easily stored onsite at generating plants, reducing the need to secure supplies before firing up the generators.
The major problem for New England is its lack of pipeline capacity to move greater supplies of natural gas into the region. Expansion of the pipeline network has been proposed. However, we are not sure whether they will be allowed to proceed; regardless, they will not be available to ease supply tightness for at least two years. Previous efforts to expand the pipeline network have faced fierce opposition from environmental groups. The irony is that rather than having lower-carbon natural gas supplies available to generate electricity, the grid burns more carbon-intensive oil.
Proposed New England gas pipeline expansion.
However, ISO-NE did experience a problem with power imports. The New England Clean Energy Connect Line (NECEC), which supplies hydroelectricity from Canada, experienced a nearly 20-hour outage that began Tuesday afternoon, May 19. Avangrid Inc., which operates the line, said the outage was caused by a “technical malfunction.” The cause of the outage remains under investigation.
Resorting to burning oil was shocking, but not surprising, given the pipeline situation in New England, and compounded by the loss of power imports from Canada. However, burning oil is associated with winter, not early summer. Last January, during a bitterly cold spell, ISO-NE was burning more oil to generate power than it had since 2018. Oil supplied over a third of the region’s power during the cold spell, which was needed because gas pipelines were full, heating New England homes.
Additionally, the NECEC, which had just come online after years of legal and political battles over its construction through Maine, was taken offline by Hydro-Québec, its supplier. A spokesman for the company said it needed to keep the power on its side of the border. “Temperatures in Quebec are the coldest on the planet right now because of a polar vortex,” Robert Dudley, Hydro-Québec’s spokeman said. “So, this is an exceptional moment; the ability of Hydro-Quebec to supply this contract throughout the year is not in question.”
NECEC has 20-year contracts with electricity utilities in Massachusetts to eventually provide enough electricity to power about 1 million homes. The problem is that the contracted supply can be interrupted, as it was during the bitterly cold period. At times during that polar vortex, New York power companies were supplying power to Quebec rather than the other way around. In the long term, Massachusetts will need to secure power supplies to offset that line, as Hydro-Québec has told the Maritimes hydropower generators that it will need the power for its customers at the end of the contract.
The ISO-NE grid was saved this time by the availability of its oil-fired generators to step up. The on-site supplies of oil and coal are important insurance policies for a grid being forcibly transitioned to meet the net-zero emissions policies of various states, which means relying on unreliable wind and solar output.
The most important point about the ISO-NE grid situation was highlighted by the first bullet point in NERC’s commentary on the grid’s outlook. NERC noted: “The New England area Anticipated Reserve Margin of 14% marginally exceeds the Reference Margin Level of 13%, avoiding a shortfall between anticipated resources and the reference level for reserves. There is, however, a 41 MW shortfall if resource additions are not included.”
If generating assets are not added to the grid as projected, it could face more operational challenges when temperatures soar or sink, when power plants are offline or fail to operate, or when imports are unavailable. Postponing power plant retirements may be necessary to ensure a sufficient reserve margin to avoid blackouts should power demand spike.
This summer, if the super El Niño creates unusually hot weather in New England, may become a challenging period for local utilities. Mandated power demand reductions, brownouts, and potential blackouts will not be welcome by the region’s residents. Those are more serious problems than high utility bills, but combined, they could spark a public backlash against utilities, regulators, and politicians. Let’s hope it doesn’t come to that.