More extreme heat means more risk for our power grid, experts say

Extreme heat like the temperatures that engulfed the Chicago area this week can stress the power grid by spiking demand for electricity. With our climate trending toward longer and warmer summers, researchers and utilities are searching for ways to prepare the grid for a hotter future.

As air conditioning units kick into high gear to keep homes and businesses cool, the same severe temperatures can directly create problems at the power stations, experts warn.

“Most grid equipment is sensitive to temperature. Even on an average day, transformers and conductors get hot during the day, when households and businesses are using more power, and then cool down at night,” Ryan Burg, a principal business analyst with ComEd, said in an email. “On the hottest days, this cycle gets worse.”

With increased air conditioning loads making transformers and conductors work harder and get hotter, the environment around the equipment warms and it can’t cool down as quickly.

“When grid assets overheat, they start to burn up the insulation that allows them to operate safely and reliably, increasing the risk of failure,” Burg said. “ComEd has found in its work with Argonne National Lab that climate change is likely to make these conditions worse in the future.”

Argonne, a federal Department of Energy laboratory based in Du­Page County, published a joint study with ComEd that focuses on how changes in northern Illinois’ climate might affect the grid.

The study states the utility’s service territory already experiences extreme weather events that pose challenges to building, managing and operating the electrical distribution grid - but those events only will increase in frequency and intensity over time.

“ComEd will face hotter and longer summers with more consistent and extreme high temperatures, and warmer winters. Similarly, changes in humidity will equate to higher midcentury heat indexes, which can have physiological effects on individuals’ capacity to cope with extreme heat, increasing the potential for public health and safety issues,” the study states. “Given that higher temperatures also decrease the capacity of transmission and distribution lines, planning for infrastructure and operations investments to cope with increasing demand and decreasing relative capacity is paramount.”

One of the ways to prepare the grid is by updating equipment using standards designed for hotter weather.

“This heat wave that we’re experiencing here, not to be glib, it’s kind of a normal day in parts of Arizona,” said Tom Wall, the director for Argonne’s Center for Climate Resilience and Decision Science. “Clearly, we can design the grid for these conditions. It just hasn’t been designed that way in parts of the country where we haven’t expected this type of heat historically.”

Another way to make the grid system more reliable would be to have battery storage that could hold large amounts of energy on stand-by for when there’s a surge in demand. Currently, storage technology doesn’t exist at such a scale.

“There’s this well-choreographed, coordinated effort to ensure that suppliers are meeting what they expect demand to be,” Wall said. “The grid has no storage; there’s absolutely nowhere in the grid - except for a few rare instances - where you store electricity.”

While the coordination between supply and demand has worked in the past, storage is going to become more important as demand for electricity increases through electric vehicles and as more renewables like wind and solar come online.

While nuclear, gas and coal plants can be turned on instantly when demand needs to be met, the same can’t be said for renewables.

“Being able to store energy somehow so that we can still consume electricity when the wind’s not blowing - but we just consume it from a battery as opposed to directly from the turbine - that’s the purpose of research,” Wall said. “There’s this deep desire to move toward renewable energy, so there’s a lot of work going into finding ways to integrate batteries and storage technology into the power grid.”

• Jenny Whidden is a climate change and environment writer working with the Daily Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see dailyherald.com/rfa.