Summer may still be a month away, but electric system operators are already feeling the heat.
With above-average temperatures forecast for much of the U.S. in coming months, system operators are facing the prospect of high electricity demand and reduced supply, which will make it difficult to keep the lights on. System operators should have expected this. After all, it is well known that climate change is driving average temperatures up and leading to more frequent heatwaves, which stress the electricity system. But many system operators still aren’t planning for this new normal. If they don’t start soon, the consequences could be devastating.
Electricity consumers in Texas saw a preview of what might be coming last week. On Friday, at the start of a multi-day heatwave, six of the state’s natural gas power plants unexpectedly went offline. As temperatures in some areas approached 100 degrees Fahrenheit, the Texas grid operator Electric Reliability Council of Texas (ERCOT) asked residents to limit their use of air conditioners and other large appliances. Most residents complied and widespread power outages were avoided. But one has to wonder – if this is happening in May, what will July and August look like?
Demand for electricity typically spikes during the warm summer months, with the highest peaks occurring during summer heatwaves, when people rely heavily on their air conditioners to stay cool.
Just as people struggle with the heat, so to do many electricity generating facilities. Natural gas power plants, in particular, operate less efficiently and so produce less output when temperatures are high. Delivering electricity also becomes more difficult as higher temperatures can impair the operation of transmission infrastructure and result in more electricity being lost before it reaches consumers.
The combination of high demand, reduced supply, and transportation challenges increases the potential for summer outages, which can be deadly.
A 2021 study found that an outage during a summer heatwave in Atlanta, Detroit or Phoenix would put at least 68 percent of residents in those cities at heightened risk of heat exhaustion and heat stroke. According to the study, public cooling centers in each city can only accommodate 2 percent of residents, leaving most with no protection against extreme heat.
This risk is not merely theoretical. Last month, the Midcontinent Independent System Operator (MISO) — the entity responsible for operating the power grid in 15 Midwestern and Southern U.S. states — predicted that above average temperatures this summer will lead to a peak in demand that is likely to exceed regularly available supply. Unless MISO can make up the shortfall — e.g., by convincing consumers to use less electricity — outages are inevitable.
Other grid operators, including in Texas and California, are also projecting high demand for electricity this summer. In Texas, ERCOT has expressed confidence that sufficient supply will be available to meet demand, but the events of last weekend are a reminder of how unplanned generation disruptions can quickly cause problems.
California is also bracing for a tough summer. The California Independent System Operator (CAISO), which manages the electricity grid for most of California and parts of Nevada, has warned of potential supply shortages, especially in late summer.
CAISO and other electricity system operators could well be underestimating the risk of summer outages. Most system operators, including CAISO, base their summer electricity demand and supply projections on historic average weather conditions. With climate change driving temperatures up and increasing the likelihood of heatwaves, historic averages are no longer a good indicator of future conditions.
Electricity system planning must account for the new reality of climate change. But that is not yet happening, even at CAISO, which has first-hand experience with the effects of climate change.
In summer of 2020, a heatwave impaired the operation of a number of natural gas power plants in California, leading to a significantly reduction in their output. Hydroelectric generation in the state was also down due to a prolonged drought, while solar generation was impaired by clouds from a storm, and a series of wildfires threatened transmission lines, which further restricted electricity supply. All of this led to two days of rolling blackouts for California residents.
A state inquiry identified “climate-change induced extreme heat” as a key contributor to the blackouts. California regulators subsequently recommended changes to electric system planning to “better account for [h]eat storms and other extreme events resulting from climate change.”
Nevertheless, CAISO based this year’s summer demand forecast on historic weather data that, it admits, “does not fully reflect” the risk of climate change-induced extreme events. For example, as CAISO has noted, the forecast does not account for the possibility of extreme heat, drought and wildfire occurring simultaneously. But precisely that combination of events occurred just two years ago and caused major disruptions to the electricity system.
It is well past time for electric system operators to recognize reality — climate change is here, and they must plan for it. A good start would be for system operators to use forward-looking climate projections to inform their assessment of electricity demand and supply.
Some in the electricity industry have already done that successfully. For example, New York’s Consolidated Edison has used climate projections to evaluate how anticipated changes in temperature and humidity will affect demand in its service territory (among other things). Unfortunately, though, this is not the norm. That is a real problem.
Unless and until things change, and system operators begin planning for the impacts of climate change, we should all brace for more summer outages.
Romany Webb is an associate research scholar at Columbia Law School and senior fellow at the Sabin Center for Climate Change Law.