A late-spring heat wave that scorched North Carolina offered a glimpse at how warmer summers and customer demand are expected to test the state’s power grid.
On June 13, the second day of a nearly weeklong stretch when temperatures reached the 90s daily in much of the state, Duke Energy customers in central and western North Carolina and upstate South Carolina taxed the electric grid like never before during hot weather.
Between 5 p.m. and 6 p.m. on that Monday, as temperatures peaked and residents cranked home air conditioners after their commute from work, customers of Duke Energy Carolinas used an all-time high 21,086 megawatt-hours of electricity.
That record, which topped the previous high set nearly six years earlier, lasted for all of two days.
On June 15, the same customers hit 21,265 megawatt hours of electricity use between 4 p.m. and 5 p.m.
People are also reading…
The company also set a separate record June 13 when Duke Energy Carolinas and Duke Energy Progress — which serves the Asheville area, Raleigh and large portions of eastern North Carolina and the Pee Dee region of South Carolina — combined to use 34,079 megawatt-hours of electricity.
Those standards likely won’t last long.
Extreme weather linked to climate change and continued customer growth fueled by North Carolina’s rising population are expected to test the resilience of the power grid and drive energy demand to unprecedented levels.
For Charlotte-based Duke Energy, North Carolina’s largest utility, those challenges already are a reality.
“We have seen storms increase in frequency and intensity in many areas, so we are working to strengthen our system to make it more resistant to outages from severe weather and to enable reliable operations in extreme conditions like high heat or freezing conditions,” said Duke Energy spokesman Jeff Brooks. “We are working to make our grid more climate-resistant, and that work is especially important on days when conditions are extreme and demand for energy is highest.”
Hot and hotter
Over the past half-century, average summer temperatures in the Triad have increased by nearly 3 degrees, according to Climate Central, a non-profit organization that tracks national and local weather trends. For the same period, the average number of summer days with above-normal temperatures jumped by 26.
Those kinds of trends are expected to continue.
The North Carolina Climate Science Report, published in 2020 by the N.C. Institute for Climate Studies, predicted that summers in the state will continue to get warmer, that there will be more days with extreme heat, that record temperatures will get higher, and that hot weather will start earlier and end later.
Overall, the report projected that average annual temperatures will rise 2 to 4 degrees by the middle of this century, depending on the pace and scale of reductions in greenhouse gas emissions.
Trends and forecasts are critical to Duke Energy’s planning process, Brooks said.
“Data is one of our greatest tools to ensure the power grid is ready for current and future weather and climate challenges,” he explained. “We use massive amounts of historical usage data to determine how much energy will need to be generated at any given time to meet customer energy needs.”
The company also is incorporating artificial intelligence to guide improvements and enhance efficiency, he added.
Cranking it up
One quirk of climate change in much of the U.S. is that summer nights are warming more than days. In the Triad, the average summer nighttime temperature has increased 3.7 degrees over the past 50 years, Climate Central reports.
While likely less noticeable than extreme daytime heat, what happens when most of us sleep still has a significant effect on electricity demand, Brooks noted.
“When we have a long stretch of days with very high temperatures and limited cooling at night, it makes air conditioners work harder around the clock and makes our grid work harder,” he said. “So we do often see higher usage trends when the hot stretches also include warm nights with limited cooling.”
Day and night, outside temperatures influence indoor climate control.
“With increasingly hotter summers, we are spending more and more time indoors, cranking our air conditioning,” said Rajesh Kapileshwari, an engineer and clean energy advocate from Winston-Salem who specializes in the design of energy-efficient, sustainable buildings. “Energy consumption is going up, and we are setting new records for power demands.”
About three-quarters of electricity in the U.S. is used by buildings, and about 40% of building electricity is used for heating and cooling, Kapileshwari noted.
“Having worked with building energy systems for three decades, I have come to realize that our buildings are inherently wasteful, and as years go by, increasingly inefficient,” he said.
Higher summer temperatures and building inefficiency multiply energy use, which further taxes the electric grid. If that electricity is generated, all or in part, by burning fossil fuels, that building’s carbon footprint also expands.
“These issues will only worsen unless we take steps to reduce our power usage,” Kapileshwari insisted. “Building more power plants to meet our increasing power demands is not a solution.”
Legislation passed by the N.C. General Assembly and signed by Gov. Roy Cooper in October 2021 called on the N.C. Utilities Commission to “take all reasonable steps” to slash carbon-dioxide emissions in electricity generation by 70% by 2030 and have them be carbon-neutral by 2050.
“While ‘greening’ of our power production to solve the climate crisis is a good first step, we must also focus on the demand side of the equation,” Kapileshwari suggested.
‘What the summer holds’
Duke Energy, whose own plan for meeting the state’s emissions targets is being reviewed by the utilities commission after being criticized by some environmental groups for not shifting fast enough to renewable sources, has made consumption a key element in its plans.
“We have set three different summer peaks so far, and it is only June,” Duke’s Brooks noted. “So it will be interesting to see what the summer holds for usage across the state.”
He offered the following tips to reduce energy use in summer:
- Set the thermostat to the highest comfortable setting. Every 2 degrees you adjust the thermostat closer to the outside temperature can save up to 5% on your cooling costs.
- Make sure air filters are clean and changed regularly. A dirty filter can increase operating costs of your HVAC unit and make it work harder when you need it most.
- Close the blinds on the sunny side of the house on warm days to keep the heat out and cooler air in.
- Use a ceiling fan, set to a counter-clockwise direction, to maintain comfort while using your air conditioning less. A fan can help you feel up to 4 degrees cooler and uses less energy than an HVAC unit. But remember, fans cool people not rooms. So turn it off when you leave the room.
- Consider using the microwave instead of stove or oven to reduce heat in the kitchen and save energy. Or use a grill outside.