Natural gas and coal generators represented almost 85% of the outages, including 2,930 MW of gas generation that was idled because of a lack of fuel.
Unit 2 of Public Service Enterprise Group’s Salem nuclear plant (New Jersey) was forced to shut down at 3 a.m. Thursday after ice clogged the screens protecting its cooling water intake. Unit 1 also reduced power to 88% because one circulating water pump was shut down. Unit 2 was listed at 3% in the Nuclear Regulatory Commission status report Feb. 1.
PJM said the system energy price rose above $1,000/MWh early Thursday “following the loss of a generator in the eastern part of the RTO.” Synchronized reserve prices exceeded $900/MWh in the Mid-Atlantic Dominion (MAD) sub-zone and $600/MWh for the RTO.
In New Jersey, the Salem Nuclear Plant had to close when ice clogged water intakes.
The reactor was still offline as of Thursday afternoon, said PSEG spokesman Joe Delmar. A similar shutdown occurred at the plant in 2010 as a result of slushy ice blocking the 70-foot filter screens. Each reactor has six pumps that move water in and out of the river, and those pumps trip when water isn’t pushed through the filters.
In Michigan, a pump failure and fire created a temporary emergency where customers were asked to shut down plants and dial down thermostats.
Armada Township — Consumers Energy said its customers’ reduced gas usage is helping it deal with a hobbled gas compressor station in Macomb County.
The news comes hours after the company’s top executive called on the company’s customers to cut usage after a Wednesday morning fire at its Ray Compressor Station. She also said there would bebrief, localized shutoffs if customers ignored the request.
Grid operators are responsible for making sure electricity supply meets demand, and they build in extra reserves so there is little danger of the system failing.
Outages occur, but mostly because of problems with the power lines and pipes that deliver the electricity and natural gas.
“Are we glad we have coal because it’s cold right now? No. We’re glad we have the generation to meet our needs, and we’re really glad that our wires aren’t falling down,” said Frederick Weston, principal and director of policy for the Regulatory Assistance Project, a nonprofit that advises utility regulators.
The power outages this week were almost all because of wires or other local delivery problems. For example, ComEd in the Chicago area reported about 50,000 outages, which a spokesman said were all because of problems with wires or other aspects of the delivery system.
For grid operator PJM Interconnection, managing the electricity generation system was a challenge this week, but there was no danger that demand would outstrip the available electricity supply, said Michael Bryson, vice president of operations.
“We were nowhere near our maximum capacity,” he said.
PJM hit its highest electricity demand of the week on Thursday morning, when the cold wave was hitting several population centers, but this level was well short of record winter demand spikes.
If temperatures had been lower and electricity demand higher, PJM and utilities have strategies for managing their systems that were developed after a 2014 cold snap.
That year’s cold led to an uncomfortably close call, with the electricity demand almost exceeding the supply, which would have led to forced outages. One problem was that many power plants that should have been available were not. In a subsequent analysis, PJM found that much of the unavailable power plant capacity was because natural gas supplies were not flowing to those plants due to constraints in their delivery systems.
But the problems went beyond gas. Of the 40,200 megawatts that were not available then, 19,000 were at natural gas plants and 13,700 were at coal plants, followed by other fuels.
The issues in 2014 led to changes in the way PJM communicates with power plants before severe weather to verify their availability, and to improved coordination between the natural gas and electricity systems to monitor the flow of gas to power plants.
Another big difference today is that grid operators and utilities have expanded their programs that work with customers to reduce energy usage at times of high demand. These “demand response” programs include contracts in which businesses and institutions get paid for agreeing to reduce their use when called upon.
PJM could have handled a much colder week, in part because of agreements with customers to reduce power use. These agreements add up to 4,800 megawatts, up from 1,500 megawatts in 2014, Bryson said. The forecasted peak demand for the entire PJM territory on Thursday was 139,950 megawatts.
In addition, utilities help to manage demand by making public statements asking customers to use less energy.
Xcel Energy in Minnesota asked its natural gas customers to turn their thermostats down in response to a low gas supply in part of its system. In Michigan, a fire at a natural gas compressor station led Consumers Energy to ask automakers to temporarily shut down factories so there would be enough gas for heating homes and other businesses.
The compressor fire and other energy concerns led Gov. Gretchen Whitmer on Friday to order state regulators to investigate the state’s energy supply and preparedness. She said the study is timely because of the increasing frequency of extreme weather, which she said is likely a result of climate change.
Consumers Energy, which has a natural gas and an electricity utility, is seeking approval for a plan to increase renewable energy and phase out use of coal by 2040. A few cold days will not change that trajectory, said spokesman Brian Wheeler.
“As long as we’re responsible in taking the right steps toward renewable energy, we will still have the electricity people need, even on days like today,” he said.