General

Peak load trend likely to continue

For the second year in a row, OPPD last year set peak load usage records for both the summer and winter seasons, a trend that is likely to continue in the years ahead.

What is peak load?

Simply put, peak load is the highest amount of electricity being used at one time. Peak load records have typically occurred in the summer, on the hottest days of the year. Winter peak loads also happen, and that has increased over the years as more customers are using heat pumps, driving electric cars and using more electricity in general.

But high temperatures aren’t the only factor behind peak load records, said Ryan Headley, manager of Energy Marketing & Trading at OPPD.

“You also have to consider other factors, like how humid it was, and what was the weather like in the days leading up to it?” Headley said. “If you’ve had a string of really hot and humid days, the system will be under more pressure and people will be using more energy. So you can have drastically different load on two 98 degree days – it all depends on those other conditions.”

Peak load records

The record peak load day for OPPD was August 2, 2022, at 2,545.8 megawatts (MW). That day also tied the record for the hottest day of the year at 101 degrees and was the third of an eight-day stretch of hot days, according to data from the National Weather Service. Temperatures twice reached 100 degrees or higher during that stretch, and the coolest day was 92 degrees.

The previous summer peak load record was on July 29, 2021, on a 96 degree day during another stretch of hot days, this time seven days of 90 degrees or higher. The day before that record was set, it was 99 degrees.

The load on July 29 was 2,499.9 MW, which broke the previous record, set on August 1, 2011. The winter load record was set on Dec. 22, 2022, with 2,091.3 MW, besting the previous record of 1,823.9 MW set on Feb. 14, 2021. Before that, Jan. 15, 2018, had been the record day at 1,773.9 MW.

OPPD will continue to grow in the coming years, with more customers coming online each year.

Energy conservation helps

“We anticipate peak loads to continue to happen every year,” said Mark Trumble, director of Energy Marketing & Trading at OPPD. “It is our responsibility to play defense against peak load. By doing that, we are keeping costs down for our customers. We have programs for our customers to conserve energy on those days, which helps keep rates lower.”

OPPD has programs designed to curtail load on the highest usage days for both large businesses and residential customers.

Trumble cited programs like OPPD’s Cool Smart and Smart Thermostat programs for residential customers and the Advanced Rooftop Unit Controller (ARC) Rebate Program and others on the commercial and industrial side.

These types of programs allow customers to help conserve energy on the days it is most needed.

Winter load is growing

While it’s not surprising that hot, muggy summer days would increase demand for electricity, winter load has grown over the years, too. While our region prepares each year for the bone-chilling months of January and February, in recent years, other states were not ready for the brutal cold, which is rare in the South.

In February 2021, a polar vortex impacted much of the central U.S., reaching as far down as Texas. Some utilities – and homes – down south weren’t ready for that arctic blast, and it wreaked havoc on systems and caused widespread outages in Texas.

The changes made after that event included increasing the generation capacity requirement for electric providers.

OPPD is part of the Southwest Power Pool (SPP) which is a regional transmission organization (RTO).

As an SPP member, OPPD must plan its generating resources to uphold certain generation requirements, such as ensuring the utility can meet its peak load, plus have a certain amount of energy – currently 15% – in reserve capacity above that peak load demand that can be called upon if needed.  That amount, which was previously 12%, is known as the planning reserve requirement.

Managing the grid

An RTO can be compared to an air traffic controller, but for the electric grid.

SPP manages the power grid in its territory around the clock. The organization facilitates grid interconnection and collaboration among electric utilities to optimize grid assets during normal and adverse events.

SPP is the balancing authority for its members, one of the requirements it carries out under the Federal Energy Regulatory Commission, said Chris Haley, supervisor of Resource Adequacy Policy with SPP.

“Reliability is the main reason for the (reserve) increase. The goal is to ensure the balancing authority has enough generation available in real time to keep the lights on,” Haley said. “The stakeholder driven Supply Adequacy working group (a group on which OPPD has a sitting member) was charged with working on these changes centered around reliability. The resource mix of the grid it is rapidly changing. It is a grid in transition for sure.”

And OPPD wasn’t alone in setting peak load records. SPP also set both summer and winter load records in 2022, a sign of regional growth and ever-increasing electrification.