Energy supply in cold weather (Meredith Angwin) USofA

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Oil Kept the Power Grid Running in Recent Cold Snap Meredith Angwin January 27, 2017

Around 5 p.m. on Jan. 6, I snapped on a light as the sun went down. The temperature was around minus 8. It had been zero at lunchtime and would be minus 15 the next morning.

As usual, the light went on. As grid operator ISO New England had planned, oil had saved the grid.

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During that very cold week, about one-third of New England’s electricity came from burning oil. The people at ISO-NE might think it is unfair to say that they planned to save the grid with oil, but they did, because of the Winter Reliability Program. But first, some background.

Over the past few years, as the price of natural gas went lower and lower, more and more natural gas has been used on the New England grid. Gas-fired plants could undercut the bids of other plants. Therefore, gas-fired plants ran more hours, and new gas plants were built. Though the overall demand on the New England grid has been virtually flat for years, more and more gas has been used to make electricity. In 2016 (the last year for which full data is available), 49 percent of our electricity was fueled by natural gas.

In many ways, having so high a percentage of natural gas on the grid was “cruising for a bruising.” Electricity must be produced at the exact moment it is needed. Oil, coal and nuclear plants are prepared for demand variations because they store fuel on site. In contrast, gas plants are supplied by pipelines: They get the fuel when they need it — if the pipeline has it available. Using natural gas for electricity means that real-time electricity meets real-time pipelines. Everything has to happen right now. Under some circumstances, it was clear that this would not end well. Homes use natural gas for heat, and homes have priority on the pipeline. In very cold weather, when homes need a lot of gas, power plant gas supplies are interrupted.

The Winter Reliability Program exists due to the foresight of the grid operator, and this program pays for oil. Many gas-fired plants can also burn oil, if they have it, and the bulk of reliability program money goes toward paying such gas-fired generators to keep oil on site. In the early evening of Jan. 6, when I switched on the light, the grid was running about 30 percent oil-fired. It had been running at that level of oil consumption for several days.

Side note: The national grid regulator, the Federal Energy Regulatory Commission, does not like the New England Winter Reliability Program because it does not like grid operators to pay directly for one type of fuel. Next year, there will be no such program.

Instead, ISO-NE will implement an untested program of fines and rewards for power plants (known as Pay for Performance), aimed at keeping the plants online in bad weather. Since the grid itself will not change, I think the new program is unlikely to change the amount of oil used on the grid.

And a note about price: In the cold weather, the price for gas was soaring. The usual daily price for natural gas in this region is about $4 dollars per MMBtu. On Jan. 4, gas was $87 MMBtu. (MMBtu stands for 1 million British thermal units. One Btu is the amount of heat required to increase the temperature of one pound of water 1 degree Fahrenheit.)

Electricity prices on the grid also ran very high. The usual grid prices of 2 cents to 8 cents per kilowatt-hour went up to 15 cents to 40 cents, and stayed high for days. (A 2

kilowatt-hour, or kWh, is the amount of electrical energy consumed when 1,000 watts are used for one hour.)

Expect all this to be reflected in your electricity bill, by the way.

Back to our grid, which was more than 30 percent oil-fired. All that oil made our winter grid more carbon-dioxide heavy than our summer grid. In planning for the future, I believe we should also think about the carbon content of the fuel. How were our lowcarbon sources of energy doing in the cold weather?

Nuclear plants made about 20 percent of the New England grid’s power, despite the fact that the smallest plant (the Pilgrim Nuclear Power Station in Massachusetts) went offline after one of its power lines went down.

Wind turbines did very well while the wind was blowing. During those times the grid received about 5 percent of its power from wind turbines. Unfortunately, a lot of the time, the grid received less than 1 percent from wind.

Hydro, biomass and refuse burning added up to about 10 percent of the power, and they were very steady.

It is very hard to tell how much solar is on the grid, because much solar is “behind the meter” and not tracked well. I would say, however, that with snow on the solar panels, we probably had less solar than usual. So, depending on the wind, we had about 35 percent of our power from very low carbon sources. And yet, there was all that oil ...

What should we do to avoid having a high-carbon grid in bad weather? The answer is simple, but not easy to implement. Basically, the way to have more low-carbon sources on the grid in bad weather is to have more low-carbon sources on the grid in good weather. Plants get stressed in various ways in bad weather, and all sorts of plants go offline. To have a low-carbon winter, we need low-carbon summers.

This will not be easy to do. We can start by not closing existing low-carbon sources (nuclear plants, hydro, wind turbines) and look at building more. However, low-carbon sources are not locally popular, and most people don’t even know about the oil-burning on the grid in bad weather. So I am not hopeful. I think there is more oil on its way for the New England grid.

I see some hope, however.

Other northern areas have low-carbon electricity, with almost no fossil fuels. Both Sweden and Ontario have very low-carbon grids, based on nuclear and hydro. Sweden and Ontario emit less than half the amount of CO2 per kWh as New England or Germany. Both these areas are also adding wind, but the basis of their low-carbon grid is nuclear and hydro.

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I wish the Northeast would follow the example of these low-carbon areas, but I fear that we will not.

Meredith Angwin, of Wilder, is a physical chemist who spent most of her career working with nuclear and renewable energy. She is a member of one of the advisory committees to ISO New England and recently published the book, Campaigning for Clean Air, which offers strategies for pro-nuclear advocacy.

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