The heatwave culminating on July 9 pushed electricity demand in the Eugene Water & Electric Board’s service territory to the second-highest level ever during the summer, the Oregon public power utility reported on July 15.
On Tuesday, July 9, temperatures hit 105 degrees and electricity demand peaked at 418 megawatts at 6 p.m. -- the second highest summer day for electricity demand ever for EWEB.
Monday, July 8, when temperatures maxed out at 104 degrees, nearly matched that demand with a peak of 416 megawatts at 6 p.m.
Demand during this heatwave was about 3% higher than similar heat waves in 2023 and 2021, when temperatures also rose above 100 degrees for multiple days.
The only summer day that had higher electricity demand was in 2006, when there was an additional large industrial consumer in Eugene that consumed large amounts of electricity -- Hynix microchip manufacturing plant.
That year, on Monday, July 24, temperatures hit 100 degrees and electricity demand topped out at 423 megawatts.
The Hynix plant opened in 1998 and closed 10 years later due to a downturn in the market for microchips. The closure of the plant, and concurrent economic recession, prompted a steep drop in electricity demand in Eugene. Since then, overall demand has stayed relatively flat while peak demand on the hottest days of the year appears to be creeping up.
“As summers get hotter, air conditioning use will only rise in our community,” said EWEB Chief Energy Resources Officer Brian Booth. “We’ve made it through the last couple decades by using energy efficiency to cut energy usage at the same rate that it’s rising. But demand is starting to outpace our ability to implement conservation programs, and we will soon need new sources of on-demand, dispatchable electricity to keep up.”
EWEB noted that in Eugene, days with temperatures above 100 degrees used to be rare. According to records from the National Oceanic and Atmospheric Administration, 2015 was the year with the most 100-degree days, with seven of them. Already in 2024, there have been five days above 100 degrees.
In general, meeting winter demand is much more challenging, with peaks reaching at least 25% higher than in the summer. Winter peaks reach as high as 500 or even 550 megawatts, and averages hover near 300 to 350 megawatts, it said.
“But summer peaks strain the distribution system more as wires sag from heat and transformers struggle to dissipate heat,” EWEB said.
“Meeting electricity demand on mild or even warm days is relatively simple. If demand for electricity were always at average levels, our task of delivering reliable, affordable and environmentally responsible power would be easy,” Booth said. “It’s the peaks that are challenging, and they are what we plan our system around. That’s why we need energy resources – like hydropower – that can generate on demand.”
EWEB noted that in Eugene, days with temperatures above 100 degrees used to be rare. According to records from the National Oceanic and Atmospheric Administration, 2015 was the year with the most 100-degree days, with seven of them. Already in 2024, there have been five days above 100 degrees.
Before the 2020s, heatwaves with 100-plus degree temperatures happened once every 10 to 20 years. But those kinds of heatwaves have struck Oregon in three of the last four summers.
Hydropower
To keep costs down during the heatwave, EWEB relied on its flexible hydropower resources -- especially its Carmen-Smith Hydroelectric Project on the McKenzie River and the flexible portion its allotment of Columbia River hydropower sold by the Bonneville Power Administration.
During the heatwave, EWEB bought energy on the wholesale market when it was cheap during the cooler hours of the day, then ramped up production at its hydropower facilities during the hot evening hours, avoiding higher market purchases, it noted.
During the coolest, lowest demand hours of the day on Monday and Tuesday -- from about midnight to 7 a.m.-- real-time wholesale energy prices were just over $20 per megawatt-hour. But at peak moments, prices reached nearly $250 per megawatt-hour.
“Wholesale electricity prices are always changing, but they become especially volatile during extreme weather events like this past heatwave,” said Chad Hadley, an EWEB power trader. “EWEB takes cues from these volatile price signals to guide when we dispatch our on-demand hydropower resources. We’re fortunate to have these resources because they allow us to minimize our exposure to the market and ultimately keep costs low for customers,” he said.
EWEB Examining Demand Response Programs
Last summer, during the August heat wave that saw temperatures crest 100 degrees for four days straight, EWEB called on customers to voluntarily trim their energy usage in the late afternoon and evening hours to avoid straining the grid.
Customers responded by raising the setting on their thermostats a couple degrees and delaying usage of major appliances until overnight, ultimately shaving energy usage by 10 to 15 megawatts during certain hours.
Since then, EWEB has been studying instituting formalized demand response programs that would reward customers for cutting energy usage at peak times.
Specifically, EWEB is analyzing what types of programs will yield the most energy savings for the investment and which will have the highest potential adoption rates.
