Power grid meets demand in deep freeze
LOWER PROVIDENCE » As snow fell, temperatures bottomed out and winds roared across much of the eastern United States over the past week, the demand for electricity increased.
Several winter peak demands for electricity were set across the region, landing among the top 10 winter demands for the PJM Interconnection, which manages the high-voltage power grid for 65 million consumers in 13 states and the District of Columbia.
On Friday evening, Jan. 5, PJM recorded its fourth-highest wintertime peak demand for electricity. At 7 p.m. Friday, demand for electricity reached 138,465 megawatts (MW). The other two top 10 winter peak demands were 136,206 MW on the morning of Jan. 5 (eighth highest) and 136,125 MW on Jan. 3 (10th highest).
PJM credits planning and lessons learned from the 2014 Polar Vortex for the resilience of the sys-
tem, according to a press release.
“After the Polar Vortex [of 2014], PJM worked with our members to better prepare to meet the demands of the system in cold weather,” said Mike Bryson, vice president — operations in the release. “We implemented the Capacity Performance construct’s strict standards for resources, strengthened communications with gas pipelines and improved preparation coordination with members. Member companies also made modifications to improve equipment performance. In the end, we saw better availability of resources during the extreme cold.”
According to PJM, generators qualifying as Capacity Performance resources must be ready to deliver electricity in a PJM power supply emergency and must have firm fuel supplies or be able to switch to a secondary fuel or fuel source.
Generators that are required to meet the capacity performance requirements and fail to produce electricity when called upon by PJM in an emergency, are subject to making performance payments, a PJM spokesperson said Tuesday.
Bryson added that PJM worked with members on cold weather preparedness, a fuel inventory survey, resource testing and a drill for emergency procedures. The cold weather exercises allow units to identify and correct start-up, operational and fuel switching issues prior to cold weather operations.
In a Tuesday press release, Exelon Generation stated that the company’s Pennsylvania nuclear plants — Limerick Generating Station, Peach Bottom Atomic Power Station and Three Mile Island Unit 1 — performed reliably throughout the cold weather period.
“Our performance this past week helps demonstrate nuclear power’s reliability and resiliency nationally,” said Chief Nuclear Officer Bryan Hanson. “Millions of people count on the electricity our nuclear facilities provide, in homes, businesses, schools and hospitals, so we prepare for winter all year long to meet our reliability commitments.”
According to the information from Exelon, nuclear facilities are not susceptible to fuel supply challenges, and typically have 18- to 24-months worth of fuel in the reactor.
According to information on the PJM Interconnection’s website, the grid operator issued a Cold Weather Alert for the entire region between Jan. 4 and Jan 7. A Cold Weather Alert prepares employees and facilities for expected extreme cold weather conditions, when actual temperatures are projected to fall near or below 10 degrees Fahrenheit.
Between Dec. 27 and Jan. 7, the average temperature across the PJM region did not reach 20 degrees, and the average low temperature was 2.9 degrees on Jan. 1.
Each year, PJM analyzes the expected demand for electricity, weather predictions and other factors to develop its forecast for the season’s operations. This year, according to PJM, the grid operator looked at the southward shift in the polar vortex that caused unusually cool weather in August. That shift indicated a risk of periods of arctic cold through the winter of 20172018, according to the release.
In response to a question Tuesday, PJM said that it is not unusual to have extremes — like those recently experienced — reach across the entire region served by PJM.