I decided to tell this blog as a series of pictures.
I will start with a screen shot that I took of the weather report, at about 5:30 this evening. (Note that "Hartford" refers to the town of Hartford Vermont, where I live.) It was 7 degrees F at that time, with a drop to minus 16 expected tonight. The next few days are expected to have single digit high temperatures and minus temperatures of two digits (minus 10, etc)
|Weather at 5:30 pm and forecast
So, how is the grid doing? Fairly well, actually. At 5:30, I took this picture, showing that the LMP (local marginal prices) were running at about 20 cents a kWh. ($200 a MWh translates to 20 cents per kWh.) The graphics below are screen shots from ISO-NE. I took my snaps at 5:30 at this ISO page, which is updated every 5 minutes. https://www.iso-ne.com/isoexpress/
|Grid prices and electricity use at 5:30 p.m. and throughout the day
As you can see by the retrospective graphs to the left of the map, prices have been up and down between $100 and $250 (10 cents and 25 cents per kWh) most of the day.
Oil on the Grid
During cold snaps, gas pipelines must supply homes first, and gas-fired power plants get short-changed. ISO-NE has a Winter Reliability Program which mainly compensates gas-fired power plants for keeping fuel on site: oil or LNG or CNG. (Liquefied or compressed natural gas.) The grid was running about 22% oil at 5:30 this evening.
The current Winter Reliability program is described in an update presentation, given December 7, 2017 by Anne George of ISO-NE. On page 5, Ms. George describes the current winter reliability program, which pays oil and gas fired generators to have fuel on site. (Page numbers are at the lower right of each viewgraph.) On page 18, she describes how the forward capacity auctions are attracting new generation, even as older plants retire. Specifically, ISO-NE is attracting new dual-fired natural gas resources: gas turbines that can also burn oil, and therefore can store oil on-site for cold weather.
ISO-NE's attempt to provide winter electricity by encouraging oil use in cold weather is working. The next picture shows (among other things) the fuel mix at 5:30 on the New England Grid.
|Fuel use at 5:30 p.m. and throughout the day
You can see that 25% of the electricity was supplied by nuclear, 24% by natural gas, 22% by oil, and 11% by renewables. Usually, the grid runs closer to 50% natural gas and just a few percent oil. If you go to viewgraph 19 of the ISO-NE presentation, you can see that natural gas is expected to be 55% of normal generation, and oil is the merest sliver on the graph.
In the chart above, renewables are making 11% of the power on the grid. This is on the high side. (Viewgraph 19 of the ISO presentation shows renewables making 5%, for example.) The high contribution of renewables is due to the wind.
In my experience of New England, really cold weather is often deathly still. Not this time. The wind is blowing, the windchill factor is serious, and the wind turbines are making considerable amounts of energy. Wind turbines are making 50% of the renewable power on the grid, as you can see in the chart below. Basically, the other 50% of the renewable power is being made by burning wood and refuse. That power is pretty steady: the wind contribution goes up and down.
Since wind is making half the renewable power on the grid, and renewables are making 11% of the power on the grid, therefore, the wind turbines are making 5.5% of the power on the grid.
The chart below shows the percentage of renewables on the grid at 5:30 p.m.
|Renewables on the grid at 5:30 p.m. 50% of the renewable power is from wind
The End of the Grid Tour
I am pleased that it is both cold and windy. (Actually, I am not that pleased about it. I have to live here, after all.) I also know ISO must be fuel-neutral, so dual-fuel gas-fired generators are considered good. However, I can't help but think that using more oil in the winter is a step back for New England, not a step forward.
If you want, you can go to the ISO site, and watch the grid. Or if you don't live in New England, look up your own grid, and do a compare-and-contrast. I would love it if you would comment on this article.
(An article from about four years ago in similar weather: The Cold Truth on the New England Grid.)