Extreme weather, such as heat waves, can negatively affect the country’s energy supply, and utility officials are taking stock of resources as summer begins.
The Southwest Power Pool is the regional transmission operator that serves 14 states in the central U.S., including parts of Missouri. SPP’s sources forecast a 40-60% chance for higher-than-normal temperatures for the summer as well as below-average rainfall for the region.
“Several days of really high heat could also make things really tight for us,” said Derek Hawkins, SPP’s director of system operations. “If that correlates with really low output in wind generation, those would be the most challenging days for our footprint.”
The SPP is reliant on wind, as that’s how more than a third of the region’s power is generated. Last year, more than 28% of the region’s energy was produced by natural gas and approximately 24% from coal. Less than 1% is from solar power.
Electric air traffic control
Transmission operators serve as a sort of air traffic control for energy generation and transport across a section of the country. While traditional power plants, such as those that run on coal and gas, are less efficient in extreme heat, Hawkins said intermittent resources such as wind and solar — that is, those dependent on weather to produce energy — create a more dynamic system to manage.
“That's why we exist, to keep things reliable and to forecast those things and make sure that we have enough generation in place to meet the variability,” Hawkins said.
The Midcontinent Independent System Operator, or MISO, is the grid operator that serves 15 states where a varying mix of weather can occur — heat waves, tornadoes and hurricanes. MISO covers the northeastern part of Missouri, and officials are also predicting sufficient energy resources are available to meet demand this summer.
Still, MISO spokesperson Brandon Morris said an ongoing effort to replace fossil fuels with renewable sources makes prediction difficult, which is why he said utilities are aiming to get new power plants online “as quickly as possible.”
“We project adequate resources are available to serve the summer demand, but we are dealing with rising risk,” Morris said. “Obviously, with an evolving energy mix, it adds uncertainty during periods of extreme weather.”
MISO’s seasonal energy assessment accounts for weather, amount of energy generated in a region, transmission line capacity and planned outages.
Juggling peak demand and maintenance
On an average spring day in Missouri with temperatures in the low 70s, MISO’s forecast demand for its 15-state service area is approximately 82 gigawatts. Prolonged heat waves mean air conditioners are frequently running, contributing to higher electricity use.
“The hotter it is and the longer that it's really hot, the higher the forecast demand is,” Morris said. “So that's when you're looking at that 123 gigawatt demand on a really hot day.”
MISO’s approximate max power capacity is 138 gigawatts.
Hawkins said for the Southwest Power Pool’s territory, spring peak demand ranges from 25 to 35 gigawatts. That spikes to around 56 gigawatts in the summer. Missouri’s portion of SPP on the western side of the state generally sees demand peak at 8.5 gigawatts, Hawkins said.
“Geographically, the size of Missouri in the SPP footprint is not that large but it is more densely populated,” he said. Missouri’s portion of SPP uses, on average, about 12% of the power available for the region.
Maintenance interrupts capacity
Power plants generally need to be turned off while undergoing maintenance, ultimately reducing the amount of energy available in a certain area. Those scheduled outages often take place in spring to avoid times of high electricity demand throughout the summer. The same situation applies to the transmission grid.
“If lines are out for repair (or) due to structural damage from storms, as an example. Essentially that limits the availability to transfer power across the system,” Hawkins said.
Morris and Hawkins both remind the public that their local utilities are the best source of energy information during extreme weather events.
“There may be some times during the summer where it's really hot outside and you may see us issue alerts and advisories. That's not a cause for panic,” Morris said. “We are issuing those alerts and advisories to our member utilities and then they pass along information directly to the consumer.”
