Can our power grid weather the heat?

Triple-digit temperatures are blanketing many parts of the United States. What started in the South and Southwest is now spreading into the Midwest and the East. Though high temperatures are common during the summer months across much of the nation, what has made this unusual is the extended time for such temperatures.

Phoenix, which often has days over 100 degrees during the summer (111 days on average per year, in fact), recently experienced 24 consecutive days over 110 degrees, with July 22 reaching 118 — a daily record. 

In another temperature twist, Las Vegas went over 290 days without reaching 100 degrees, which ended one month ago. It is now experiencing triple-digit temperatures like much of the Southwest, reaching 115 degrees on July 22, eclipsing an 86-year-old record.

Even northern cities like Minneapolis will be flirting with triple-digit temperatures this week, though the record of 108 degrees set back in 1936 is in no danger of being broken.

With much of this heat comes high dew points, which makes the heat feel more uncomfortable. This has pushed the heat index in many areas persistently into triple digits.

We are not alone, of course. Triple-digits temperatures are ubiquitous across the Middle East, with the heat index in some areas topping 140 degrees.   

What most of us do when the heat index soars is turn up the air conditioning. This works well when staying indoors. However, people who must be outdoors for extended periods, like construction workers, must bear the brunt of the heat and intense sun throughout the day. Shifting shifts from 10PM to 6AM is one solution, if artificial light can be used to complete jobs. 

For most, running air conditioners nonstop is the solution. Yet air conditioners run on electricity. July and August have historically been the highest electricity consumption months in the United States. This year will be no exception.

When air conditioners are used at record levels, demand on the electricity power grid is strained.

The power grid for most is “out of sight, out of mind,” provided it delivers the electricity to fill our needs. Yet how reliable is the power grid? To answer this question, knowing how electricity is generated would be informative.

We would like to believe that wind, solar and hydro are the dominant sources, given that they are renewable and widely promoted. However, just over 21 percent of all electricity generated is from renewable sources (as reported in 2022). Around 18 percent are generated by nuclear power plants, around 20 percent are generated from coal burning plants, with the rest (around 40 percent) generated from burning natural gas.

When demand for electricity surges, where does the extra electricity come from? It depends on where excess capacity exists.

The largest electric generation capacity are natural gas plants, followed by non-hydro renewable and coal.  Ths suggests that when extra capacity is needed, much of the extra capacity is generated using fossil fuels.

This should not be surprising, given that passive production from wind and solar are subject to nature and can be less predictable than burning natural gas or coal.  

There is also the issue of what happens when demand is pushed closer to (or exceeds) capacity. Will the system remain reliable and functioning? Much like how we use our air conditioners, if its use is pushed to capacity over extended time periods, will it continue to function reliably and effectively?

The power grid has remained remarkably stout, in spite of its many problems, including its fragmented infrastructure. Some view it as being fragile, in that extreme events can put it at risk for failure. The growth of electric cars has added additional demand on the power grid, adding to its strain.

It is rare that blackouts or brown-outs occur in the United States, even under the most extreme conditions. Yet excessive heat and cold represents extreme conditions that place pressure on such systems. Recall the February 2021 cold weather that crashed the power grid in Texas, leaving millions of people without power and heat.

Extreme weather events are a call to strengthen the nation’s power grid. Reliable electricity is an important driver of economic growth and population wellbeing. Though crises provide the motivation to plan for the future, planning for the future will unfortunately not help during the current heat wave. A future, with a strengthened power grid, is imperative; let’s put today’s triple-digit temperatures to good use.

Sheldon H. Jacobson, Ph.D., is a professor in Computer Science at the University of Illinois Urbana-Champaign. A data scientist, he applies his expertise in data-driven risk-based decision-making to evaluate and inform public policy.