How to keep AC from knocking out power becomes focus as Colorado heat waves intensify
Heavier reliance on air conditioning to keep cool threatens to knock out electricity more often as heat waves intensify, and Colorado officials this week are seeking utility “readiness” assurances after temps topped 100 degrees.
A combination of earlier-than-expected extreme heat, extended drought and wildfires that can destroy transmission lines has raised outage risks, especially in the West. Shrinking water means hydro-power turbines atop the Grand Canyon may no longer turn.
While electricity grids in Colorado have proved relatively resilient, “this is a larger issue than it has been in the past,” Colorado Energy Office director Will Toor said in an interview Tuesday.
“It’s important for utilities to really be ramping up their demand-response programs to help manage peak needs. We’re going to need a real focus on resource adequacy as we move into this world of longer heat waves, more intense heat waves, and loss of hydropower,” Toor said.
Colorado residents traditionally have treated air conditioning as an optional amenity. That’s changing. “As summers get hotter, we are, increasingly, going to see cooling as a real need,” Toor said. “We are entering into a world where AC is going to be more and more important for health and safety through these long heat waves.”
The president of Colorado’s largest electricity supplier — Minneapolis-based Xcel Energy – acknowledged strains but told the Denver Post planning has paid off.
This week’s heat wave across the West “does present challenges for us. But we are prepared for those challenges,” Xcel-Colorado president Robert Kenney said, pledging full cooperation with state regulators.
“We know the higher temperatures, and sustained higher temperatures, are climate-driven. We are prepared. We have our own meteorological studies. We pay attention to the National Oceanic and Atmospheric Administration. We make sure we have adequate resources on line,” Kenney said.
This spring, Xcel teams handled scheduled maintenance at power plants early to boost readiness for anticipated summer demands, Kenney said. And extra electricity generated for meeting peak demands has been increased.
Heat waves typically bring the greatest challenges for utilities, often in late afternoon as residents return to homes and dial up AC.
Colorado’s expanding population means additional strains. Xcel now serves 1.5 million households and businesses here (3.8 million in eight states overall), up from around 1.2 million a decade ago.
State regulatory officials on Tuesday couldn’t say how many times a year electricity plants failed to meet demands, but they cited an industry standard measure of reliability — outage minutes a year per customer — that in 2021 ranged from 57.6 minutes to 236.4 minutes around Colorado. That was below a national average of 280 minutes.
Around the West, rising demands for electricity have overwhelmed power grids in California, leading to rolling blackouts. In Texas, more than 200 people died when extreme winter storms in February 2021 led to blackouts.
Colorado officials anticipate more summer days with temperatures exceeding 90 degrees and 100 degrees. Since the start of the 20th Century, Colorado’s average temperatures have increased by 2.5 degrees, and the numbers of very hot days increased over the past two decades, according to a 2022 National Oceanic and Atmospheric Administration summary. “Historically unprecedented warming is projected during this century.”
On Friday, Colorado’s Public Utilities Commission is scheduled to explore utility readiness to meet increased electricity demands this summer and next.
PUC officials want to know about “plant outages, tight regional electricity markets, and unanticipated risks surrounding the near-term completion of certain solar projects,” an agency spokesman said. Xcel officials are expected to address “resource adequacy in the coming years” and the broader situation around the West.
Colorado officials in recent years have pressed utilities to shift off coal-fired power plants and install cleaner solar and wind systems for generating electricity. Xcel officials recently agreed to close their massive coal-fired Comanche power plant east of Pueblo by 2031, faster than their long-planned 2035 closure.
At present, utilities in the state burn coal to generate 36.7% of the electricity residents use (above the national average 21.6%). They rely on renewable sources (mostly wind) to generate 35.7% of electricity and methane for a 25.9% share, according to federal energy records.
Colorado’s electricity use per person has been lower than in two thirds of states, federal records show, but more residents are switching from gas-powered to electric vehicles. This has led to more drivers tapping an estimated 3,500 public vehicle fast-charging ports installed around the state.
The North American Electric Reliability Corporation warned, in its latest summer assessment, that energy emergencies are possible due to climate warming and utilities shifting off coal generators toward wind and solar power. The NERC assessment cited climate warming impacts on hydropower, wildfire threats to transmission lines, and challenges of relying on intermittent wind and solar sources of electricity.
President Joe Biden has called for “de-carbonization” of the U.S. power grid before 2035 – an effort to contain the emissions of heat-trapping gases that accelerate climate warming.
One way power plants can increase grid resilience may be storing energy in batteries as backup to deal with sudden heavy demands. Xcel officials have proposed installation of up to 400 megawatts of energy in batteries under a plan that PUC officials are reviewing.
When electricity demands surge, other utilities sometimes seek help from Xcel sharing supplies. Utility officials on Tuesday couldn’t say how often that’s happened this year. Xcel president Kenney cited looming loss of hydro-power in the West as “a constraint we’re definitely monitoring.”
Shifting to clean energy complicates grid resilience “but Xcel’s commitment to bringing more renewables is unwavering,” Kenney said. “The fact that we’re seeing higher heat sustained for longer periods” shows the “the need to continue to deploy renewable” electricity systems, he said.
“We’re going to see the weather evolve — driven by climate change. No question about it. We see the evolution in the form of stronger winds, higher temperatures, more persistent drought. This makes it more urgent to deploy more renewable energy resources — to de-carbonize. We have been planning for this, and there are technologies that don’t even exist yet that will help us combat climate change.”
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