This week’s anecdote, insight, or observation
Winter Storm Fern pushed exceptionally low temperatures across the US for several days.
The resulting need for indoor heating caused electric power demand to spike.
What happened in the Northeast is particularly notable. It shows us both the challenges and the opportunities we face as we remake the electric grid during an era of strong demand growth.
To meet demand, the Northeast started burning oil as its primary fuel source to generate electricity.
That’s not normal.
On average, oil and distillate fuels are responsible for about 1% of power generation in the Northeast.
As Winter Storm Fern set in, over the course of just a few hours oil went from supplying next to no power to being the largest contributor to the Northeast’s generation mix.
Check out this chart from the US EIA:
Petroleum generation hit nearly 8 GW at the peak. That’s more than New England’s installed petroleum-only capacity.
The difference came from fuel switching: natural gas plants that can also burn distillate oil when gas becomes too expensive or unavailable.
That hidden flexibility is what kept the lights on.
Why did this happen
Three reasons.
First, variable renewables aren’t dispatchable. You can’t demand the sun shine longer or with greater intensity. The same with the wind. When demand spikes, you often have to turn to dispatchable fuels.
Second, utility-scale batteries typically have discharge durations measured in hours. You can see from the chart above that the call on oil lasted for days. We don’t yet have storage that can bridge a multi-day demand surge.
Third, natural gas prices spiked with the increasing power demand. Supply was constrained when some production was taken offline due to freeze-offs. With gas too expensive or unavailable, oil became the backup.
This isn’t the first time.
Winter Storm Uri rolled through almost exactly five years ago. The same thing happened then: record demand spikes overwhelmed parts of the power sector.
Two major grid stress tests in five years. We should expect more.
If another record-breaking winter storm sweeps the country within the next five years, what meets that demand spike?
The honest answer: everything we can muster.
Within that timeframe, variable renewables, batteries, natural gas, and even oil as a backup, are the options available at scale. Nuclear won’t be deployable fast enough to matter for the next event.
Winter Storm Fern is a reminder that grid reliability isn’t about choosing the “right” power source. It’s about having enough dispatchable capacity to meet demand when conditions turn extreme.
We can debate the long-term generation mix. But in the short term, flexibility wins.