By RTO Insider Staff

Grid operators turned to coal- and oil-fired generation last week as Arctic air sent temperatures plunging to record lows from the Great Plains to the Deep South.

The frigid temperatures caused a spike in demand for electricity, with ERCOT and SPP recording new winter demand peaks.

The most severe test of the grid since 2014, the cold blast came a week before FERC is set to respond to Energy Secretary Rick Perry’s call for price supports for struggling coal and nuclear plants in organized markets. Grid operators have managed to endure the cold weather and pinched fuel supplies, thanks in part to rule changes and winter preparations put in place after the cold snap of 2013/14.

The weather brought snow as far south as Florida and Texas, and a Nor’easter at the end of week caused blizzard conditions and coastal flooding from New Jersey to New England.

Temperatures were as low as minus 45 F, in Minnesota and North Dakota. The weather broke low-temperature records in several areas of the country. Wind chill records were also shattered. Mount Washington, N.H., recorded a temperature in the minus 30s, but with hurricane-force winds in place, wind chills were in the 80s and 90s below zero on Saturday morning. Wind chill warnings were in effect through Sunday morning in parts of the Northeast, with values expected as low as 45 degrees below zero.

On Thursday, natural gas prices at Transco Zone 6 New York hit a record $175/MMBtu, according to Natural Gas Intelligence, and averaged $140, up almost $92 from the day before. Prices at other trading hubs in New York and New England also exceeded $100 on Thursday, Bloomberg and NGI reported, with New England Internal Hub prices topping $300.

By contrast, gas futures have averaged less than $3 on the New York Mercantile Exchange this winter.

ISO-NE

The New England grid was most challenged by the low temperatures. A combination of factors led ISO-NE to begin “posturing” generation units, in which the RTO staggers their operation in an effort to conserve fuel.

Nonetheless, the grid operated reliably throughout last week, according to spokesperson Marcia Blomberg.

From Friday to Sunday, ISO-NE sent out Cold Weather Watches, issued when extreme cold weather is in the forecast but the RTO still expects a capacity margin of 1,000 MW or greater.

By Monday, temperatures in the Mid-Atlantic and Northeast began to normalize and are expected to continue rising to above-average levels later this week. ISO-NE reported 1,381 MW of surplus capacity to meet Monday’s expected peak of 20,000 MW.

But the cold, and the high demand for heating, led to pipeline constraints and a spike in natural gas prices, forcing the RTO to rely on oil-fired and dual-fuel resources. Oil was providing one-third of ISO-NE’s electricity as of Saturday afternoon, with natural gas at 24%, nuclear 22% and coal at 5%. For all of 2016, by contrast, coal and oil generation together accounted for 3% of total energy production, with capacity factors of 15% for coal and 2% for oil. Gas-fired plants normally account for about half the region’s generation.

“During this extreme cold, some power plants have either tripped offline or had to reduce their output, while other oil-fired and dual-fuel generators are quickly depleting their fuel supply,” Blomberg said Sunday.

One of those plants was Entergy’s Pilgrim Nuclear Power Station in Plymouth, Mass. It went offline Thursday after one of its interconnections failed during the storm, but the outage did not affect reliability, ISO-NE said.

Some oil units were also nearing their emission limits Sunday, Blomberg said.

As a precautionary measure before the storm, the RTO on Wednesday issued a Master/Local Control Center No. 2 alert, which requires generation and transmission owners to stop any routine maintenance, construction or test activities on their equipment.

NYISO

NYISO experienced similar conditions as ISO-NE: increased natural gas prices and a reliance on oil generation. But the ISO also said it did not have any reliability problems, and it did not experience concerns of fuel scarcity or emission limits.

“We’ve had no forced outages of the high-voltage direct current transmission system,” Vice President of Operations Wes Yeomans told reporters during a teleconference Thursday afternoon.

“The transmission system between central and eastern New York is fully loaded, as expected, bringing the less expensive energy from the western parts of the state to the high demand zones in and around New York City,” Yeomans said. In addition, the ISO was reaching out to TOs in the southeastern part of the state, which was bearing the brunt of a blizzard.

NYISO’s marginal cost of energy spiked to $229.62/MWh last Tuesday, up from $15.87 on Dec. 24. The ISO’s real-time LMP zonal map showed power from Hydro-Québec priced at $226.87/MWh, compared with $15.41 a week earlier.

Gov. Andrew Cuomo on Thursday declared a state of emergency for the city, Long Island and Westchester County because of the storm. Meanwhile, Upstate saw lake-effect snow, followed by subzero temperatures. A wind chill advisory warned that temperatures could feel as low as minus 42 F.

PSEG Long Island on Thursday reported that about 3,818 of its approximately 1.1 million customers across Long Island and the Rockaways were without service. By Monday, that figure had dropped to about 100.

NYISO Executive Vice President Rich Dewey said during the press conference that Albany had endured six consecutive days during which the low temperature fell below zero and the average was 10 F. Such weather is not unusual, but extended periods of it are, he said.

Nearly 50% of New York’s generating fleet is able to switch to oil, which helps grid reliability, Dewey said, adding that operational enhancements made after the 2013/14 cold snap include increased surveys of generators to ensure they have adequate fuel supplies. The storms also kept the 100 MW of nameplate wind running strong, he said.

PJM

PJM’s peak demand hit 138,465 MW at 7 p.m. Friday, the fourth-highest peak on record. The RTO said demand was about 2,500 MW above the forecast because temperatures and wind chill factors were lower than expected.

Demand had hit 136,206 MW Friday morning and 136,125 MW on Wednesday, the eighth- and 10th-highest, respectively.

Coal supplied 39% of PJM’s generation between Jan. 1 and 6, with a peak of 44% early Jan. 4. Nuclear provided 29%, with natural gas kicking in 21%, oil 5%, wind 3%, hydro 1% and other renewables 1%.

During all of 2017, nuclear led with 36% of generation, with coal representing 32%, and natural gas and oil at 27% and 0.3%, respectively.

Real-time LMPs were consistently above $250/MWh during the week and briefly exceeded $750/MWh in some zones.

PJM said it had been preparing for cold weather since the fall, when the National Weather Service noted that a dip in the polar vortex, which caused an unseasonably mild August, would likely return during the winter. Chris Pilong, who manages PJM’s dispatch, said the long-range forecast called for a mild winter overall with periods of extreme cold.

The RTO started issuing cold-weather alerts prior to the holiday break to ensure generators and transmission operators were prepared for frigid conditions. Communication is central to PJM’s response, Pilong said.

PJM issued a heavy load voltage schedule warning Thursday as a precautionary measure to help maximize power transfer capability and reactive reserve for the evening peak. Despite the warning, the RTO reported having maintained adequate power supplies and operating reserve margins during the cold weather.

The RTO reported no concerns with fuel availability or reliability issues through the weekend.

ERCOT

ERCOT reported a new winter peak demand of 62.86 GW between 7 and 8 a.m. Wednesday, when freezing temperatures covered much of the state, exceeding last Tuesday’s evening peak of 61.95 GW. Both broke the previous winter mark of 59.65 GW, set a year ago on Jan. 6.

ERCOT had more than 70 GW of capacity available during the morning hours. The ISO in November projected a winter peak of slightly more than 61 GW and said it would have as much as 81 GW of total resource capacity on hand to meet demand.

Wholesale prices peaked at $70.02/MWh during the interval ending at 9:30 a.m. but were as low as $32.40 in the early morning hours. Last Tuesday’s prices peaked at $72.26 during the interval ending at 6 p.m.

ERCOT did not take any extreme measures in meeting the winter demand.

MISO

MISO on Monday said it navigated the extreme weather event without a single reliability issue. The RTO recorded a peak load of 104.7 GW during the week, set on Jan. 2.

“Lessons learned and applied since the polar vortex — including increased electric-gas coordination — improved MISO’s ability to respond to challenging situations,” spokesperson Mark Brown said.

The extended cold snap prompted MISO last Tuesday to issue a conservative operations order until Jan. 5. A cold-weather alert remained in place until Sunday “due to very cold temperatures, high system load and uncertainties in gas pipeline fuel supplies.”

MISO’s all-time winter peak demand was 109.3 GW on Jan. 6, 2014.

The RTO has placed more weight on winter preparations since the 2013/14 winter, issuing winterization guidelines for generators and introducing heightened communication with gas pipeline operators. (See FERC Approves MISO Plan to Share Generator Gas Data.)

Last Tuesday, coal generation made up a 48% share of MISO’s fuel mix, with natural gas supplying 22% and nuclear and wind generation contributing about 14% each. The RTO’s mix is typically 34% coal, 41% gas, 8% nuclear and 14% renewables.

SPP

SPP on Monday reported a new winter peak demand record of 41,014 MW, set the morning of Jan. 2. The previous record was 40,322 MW.

The RTO issued a cold-weather alert for Dec. 29 to Jan. 4. Spokesman Dustin Smith said member companies were experiencing “slower-than-normal” start times and other temperature-related start-up issues at some units.

While the cold temperatures had some impact, SPP has not “encountered anything unmanageable,” Smith said. Some gas units have been unable to procure fuel, resulting in outages and switches to more costly oil.

Michael Kuser, Rory D. Sweeney, Amanda Durish Cook, Tom Kleckner, Rich Heidorn Jr. and Michael Brooks contributed to this report.