Surviving the Polar Vortex: A Look at How the Electricity System Fared

Last week, parts of the Midwest and Northeast reached
nostril-freezing
temperatures, with wind chill colder than 60
below in some areas.

Amid the dangerously frigid temperatures, the Trump
administration’s recent policy efforts to boost coal and nuclear
power meant there was extra attention paid to how different sources
of electricity handled the cold. As residents across the Midwest
and Northeast dug out of the deep freeze, power producers,
regulators and experts debriefed the results.

Reports suggest that nuclear, gas, coal, wind and solar all
faced some challenges in the numbing cold, but generally fared
well.

“On the whole, each asset class pretty much ran exactly as
designed/expected,” said Brett Blankenship, research director at
energy research and consulting firm Wood Mackenzie, who analyzed
data on the impacts across the impacted regions.  

But even as the industry commends the smooth functioning of the
system, a shifting resource mix supplying electricity is creating
fresh challenges. The U.S. Energy Information Administration
forecasts
that renewables as the fastest growing sources of electricity for
at least the next two years. At the same time, coal faces
extreme headwinds as more and more plants retire.  

Managing the Grid

Grid operators in the Midwest and Northeast, PJM Interconnection
and the Midcontinent ISO (MISO), both prepped for the cold with
weather advisories.

Despite putting all generators on deck with the declaration of a
“maximum generation event,” MISO’s system, which services at
least parts of 15 states and Manitoba, didn’t reach an all-time
peak. The operator reported that the record stayed in 2014, when
the peak hit 109.3 gigawatts, compared to the January 30 peak of
100.9 gigawatts. 

A spokesperson with Xcel Energy said the utility coordinated
closely with MISO during the period of rock-bottom temperatures.
Parts of Xcel’s service territory in Minnesota saw the lowest
temperatures in two decades. 

“Being part of a larger system like MISO helps ensure that we
can meet demand in our service area during extreme conditions,”
said the utility in a statement. “MISO called for maximum output
during the cold snap, which we provided, as it operated under alert
conditions.” 

PJM did not call a maximum generation event, and according to
senior director of system operations Paul McGlynn, the operator was
actually at times exporting power to MISO. 

“We had ample resources throughout the event, plenty of
reserves,” said McGlynn. Though PJM is still finalizing its data,
McGlynn expects last week’s weather to rank fourth among all-time
winter peak loads. 

In a
note
summarizing operations during the cold, PJM — which
manages electricity in 13 states
and D.C. — reported that forced capacity outages were also lower
in 2019 than in previous extreme weather scenarios. In the winter
peak of 2018, for instance, PJM had 12.1 percent forced outages.
The 2014 polar vortex was even higher, at 22 percent forced
outages.

In comparison, forced outages on January 30 and 31 reached just
8.6 percent and 10.6 percent of capacity, respectively. McGlynn
said the data is “certainly trending in the right
direction.”

“The system is performing better,” he added.

FIGURE: PJM Forced Outages

 

Source: PJM Interconnection

This year’s mechanical outages were dominated by coal and
natural gas (PJM’s generation varies by time of year, but on the
day this story was published the majority was divided between coal,
gas and nuclear), with some gas supply outages as well on January
30 and 31. While PJM said forced outages “were slightly greater
than normal,” it noted that’s the norm in extreme cold
events. 

The resilience and resource debate

Though potential federal plans to offer financial
support to coal and nuclear plants
seem to have been shunted to
the back-burner, last week’s challenging weather once again
brought those debates to the fore.

In most natural disasters, like wildfires and hurricanes, damage
to transmission and distribution causes the majority of electricity
disruptions — something renewables advocates say can be managed
with a distributed grid. But very cold or hot weather complicates
those arguments, because the power generation source may be most
impacted, either because of fuel shortages or mechanical issues
caused by extreme temperatures. 

While previous winters have brought reports of
frozen
coal piles and limited gas
supplies
, those were less of an issue last week than mechanical
malfunctioning.

As noted in PJM’s report, both coal and natural gas plants
were taken offline due to mechanical issues.

In Xcel territory, the utility experienced low pressure on its
natural gas pipeline system in Princeton, a small town north of
Minneapolis. The utility said it provided lodging and space heaters
to customers until service could be restored. A spokesperson said
Xcel is now working to identify possible solutions, including
possibly adding infrastructure in the area.

Aside from the problems in Princeton, Xcel said it experienced
no supply or usage issues with its coal or natural gas generation.
The utility did, however, asks consumers to moderate gas usage
until temperatures rose. Consumers Energy, in Michigan, asked the
same. A spokesperson with Consumers said the utility’s generation
fleet “performed very well” during the cold and the utility
specifically noted that no coal generation was lost due to the
weather.  

A spokesperson with Commonwealth Edison, the largest utility in
Illinois, also said all generation sources “performed as
expected.” However, the utility did face some outages tied to
transmission and distribution issues. 

Mixed results for clean energy resources

For clean energy sources, results were similarly mixed. 

In New Jersey, ice disrupted service at a nuclear reactor that
PSEG has
filed
for subsidies to support. Aside from that hiccup, Wade
Schauer, research director of WoodMac’s Power & Renewables
division, said “nuclear did amazingly well.” 

Exelon, which partially owns the plant in New Jersey, said its
plants in Pennsylvania, Illinois and New York operated at full
capacity through the low temperatures.

Schauer said wind was the most volatile resource.

“We expect wind to be volatile,” Schauer said. “But during
extreme events, volatile or intermittent generation makes managing
the grid more challenging.”

In PJM’s analysis, renewables fit in the “other”
category for forced outages (in the figure above), with 1,845
megawatts going offline on January 30, and 3,311 megawatts going
offline on January 31. Forced outages on Jan 31 also include the
roughly 1.1-gigawatt nuclear reactor in New Jersey.

While McGlynn said PJM definitely experienced wind-related
issues, he expects there were solar outages, too. The grid operator
is still working on analyzing that data. 

In extreme temperatures solar panels can be less efficient.
Batteries are also able to store less power. And wind turbines
often can’t function in extreme cold, which can ice over blades,
or in high winds. 

“This does not mean renewable energy is not good, but it just
means different types of generation have different features,”
said Zhaoyu Wang, a professor of electrical and engineering at
Iowa State University. 

Xcel noted that its wind farms in North Dakota and Minnesota
reached the low temperature threshold at which they automatically
stop operating on the night of January 29. They remained offline
until noon the next day.

Overall, grid operators and utilities felt the system handled
the bracing cold well. But that system is changing, with more
renewables and gas and less coal. Operatores note past cold winters
have been instructive, but strategies to keep electricity and heat
available will have to change as the grid does.

Source: FS – GreenTech Media
Surviving the Polar Vortex: A Look at How the Electricity System Fared