US Grid Operator PJM Battles Demand Amid Record Heatwave

As the U.S. grapples with escalating power demand due to searing heat, scientists globally warn that July is likely the hottest month ever recorded.

Nicholas Delate


Nicholas Delate


Feb 22, 2024

US Grid Operator PJM Battles Demand Amid Record Heatwave

Unprecedented Heatwaves Surge Electricity Demand and Break Global Records

In the face of escalating summer temperatures, the United States' largest grid operator, PJM Interconnection, has issued a heat alert from 26-28 July. The proactive measure seeks to ready transmission and generation facilities across its region, as the ongoing heatwave threatens to test the limits of the US power grid.

The alert follows the surge in temperatures over 90°F (32.2°C) across PJM's operational territories. PJM Interconnection oversees the electricity transmission grid across 13 states, including Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and the District of Columbia.

The reason? Increased heat and humidity can lead to potential capacity issues on the grid, right as increased usage of electric cooling systems can stress power supplies to the point of outages.

Heat Alert Amid Record-Breaking Demand

PJM anticipates electricity load requirements of around 150,700 megawatts (MW) for the day of the alert and estimates a further rise to 152,800 MW on July 28. These predictions are nearing the summer peak demand for electricity, projected at approximately 156,000 MW.

While PJM's reliability studies suggest the possibility of loads exceeding 163,000 MW, the operator is prepared. With about 186,000 MW of installed generating capacity, PJM ensures the availability of reserve resources to cater to customer needs. By comparison, the peak demand in the previous year was approximately 149,000 MW.

Just two weeks prior to PJM's warning, Texas' Electric Reliability Council (ERCOT) reported record-breaking electricity demand on the grid, reaching 81,406 MW. Their supply and demand dashboard indicates the potential for even higher peaks in the near future.

So far, the grid has outlasted the heat. But the question remains whether U.S. consumers can outlast prices. Spot market prices for next-day power reached their highest level since February at the PJM Western Hub, spanning from northwestern Pennsylvania to Washington, D.C., as forecasted scorching temperatures are anticipated to surge the demand.

Scientists Declare July as Earth's Hottest Month Ever

In response to the impending heatwave, grid operators nationwide issued hot weather alerts this week, advising energy providers to postpone non-essential maintenance to ensure that all generation plants and power lines are prepared for operation.

The heat alert arrives amid one of the hottest summers in US history. An alarming spike in global temperatures has led scientists to project that July will go down as the hottest month ever recorded on Earth, marking a worrying upward trend amid intensifying heatwaves spanning three continents. 

Four consecutive days saw the hottest temperatures ever recorded, with an average global temperature of 63.01 degrees Fahrenheit, according to data from the University of Maine and the National Centers for Environmental Prediction.

The prolonged U.S. heatwave, which has blanketed the southern regions of the U.S. for weeks, has now extended into the Plains, Midwest, Mid-Atlantic and Northeast. Axios reported that as of Thursday, the National Weather Service (NWS) has issued heat alerts affecting more than 227 million people.

The soaring temperatures, particularly noticeable in the U.S., Europe, and China, have led to a surge in heat-related illnesses. This includes the U.S. heatwave which is forecasted to extend into August, as well as a heatwave in Europe dubbed Cerberus that led to power outages in Italy and wildfires in Algeria and that continue to blaze across Greece, resulting in over 40 deaths and displacing thousands from their homes.

Across the U.S., relentless heatwaves have impacted tens of millions of people. Phoenix is expected to be the first major U.S. city to register an average monthly temperature at or above 100°F, having already surpassed its previous record of 18 consecutive days with temperatures reaching or exceeding 110°F.

The intense heat is predicted to linger across a vast portion of the country until Friday, presenting a clear and immediate threat to public health. In the U.S., enduring heat events are the leading cause of annual weather-related fatalities. The risk of heart attacks can 2x during heatwaves, so many heat-related deaths go unreported because they are misclassified.

Grid under strain

These baking summer temperatures across the U.S. are challenging the resiliency of the nation's power grid, as the intense heat fuels record electricity demand and confronts the system with strains like it has never experienced. For instance, the Texas grid set a new all-time peak load record on June 27th, and the city of Houston is expected to break its own energy demand records five times this summer alone.

Previously, the North American Electric Reliability Corp. (NERC) national grid watchdog issued warnings that two-thirds of North America could face power shortages during extreme weather. While NERC predicted no problems under typical weather conditions, they flagged that a prolonged "heat dome" could trigger emergencies in several regions, including the Pacific Northwest, Sun Belt, Southeast, and Texas.

These unprecedented weather extremes are creating an additional strain as the U.S. gird pivots towards cleaner, but intermittent, renewable energy sources. The transition from dispatchable facilities like coal and gas plants to less predictable wind and solar energy is making the management of the grid more intricate.

While the near-term response from many officials and regulators has been to rely on existing fossil fuel infrastructure as a safeguard, some believe the infrastructure itself can be prone to stress during extreme heat and potential supply issues. A report by Regenerate California, a coalition of environmental groups, found that gas plants underperformed during a heatwave last summer, suggesting the need for greater investment in wind and geothermal.

This summer is record-breaking partly because of an El Niño event and a volcano warming parts of the Pacific Ocean. These events may increase in occurrence, so grids will need to get better at anticipating them and being proactive. One such study used AI to predict these types of events and was able to do so better than traditional forecasting events.

To combat this issue, the U.S. government will spend $7 million to develop better weather predictions for extreme heat and other extreme weather events, and add $152M to drinking water infrastructure and climate resilience in California, Colorado, and Washington. The combination of high temperatures, winds, and low humidity were catalyzing critical fire conditions across regions of California, Idaho, Montana, and Nevada, impacting over 1.6 million individuals.

Texas as case study

Texas has been a hotspot for this grid reliability debate. Warnings were issued about potential blackouts if demand outstripped fossil fuel and nuclear plant capacities, but the lights have stayed on largely thanks to renewable energy. Data analyzed by the American Clean Power Association from ERCOT revealed that during the peak 10% of demand hours from June 19-30, renewable resources provided an average of 30% of electricity.

The state's competitive market and previously hands-off approach to regulations have made it a leader for wind and solar generation, which are currently more affordable than other power sources. Renewables represent nearly a quarter of ERCOT's generation capacity, equating to more than 22,000 MW. Experts argue that this volume has proved invaluable during the heatwave, especially given higher than typical outages from traditional coal, gas, and nuclear plants.

Renewables' contribution, however, brings potential risks. While the sun aligns with heatwaves, solar panels don't generate electricity at night. Wind isn't guaranteed to blow during these periods, and affordable and reliable batteries capable of storing and dispatching power are not widely available to play a significant role for grid operators. A system heavily reliant on wind and solar power without proper measures could be risky. 

Even with its notoriously strained system, Texas has thus far withstood the heat. But this week's sweltering weather, coupled with even hotter days expected, could push the grid to its limits Following 11 demand records set last summer, the ERCOT projects usage will peak at 83,402 MW on July 31 and 84,386 MW on August 1. These estimates will mark the sixth and seventh record highs this summer, superseding the current all-time high of 82,592 MW set on July 18.

To put it into perspective, one megawatt can supply power to approximately 1,000 U.S. homes under normal conditions, but this figure dwindles to around 200 homes during a hot Texas summer day. 

The consequences of the heat has already been dire. In Austin, Texas, emergency calls for heat-related illnesses in July have seen a significant uptick, double from the same period last year. In Houston, an increase in heat-related illness calls has been reported, with three deaths due to heat since June.

Even still, Dr. Thomas Overbye, an electrical and computer engineering professor and the director of Texas A&M's Smart Grid Center, expressed optimism about Texas’ ability to withstand the heat amidst the heat advisories and record energy demand. 

Overbye claims the diversity of Texas' energy supply forms the basis of his argument, as the state boasts a wide-ranging energy mix that spans nuclear power, coal, natural gas, wind generation from the Gulf Coast, and solar. 

The most challenging scenario for Texas would be a combination of high energy demand, extreme temperatures, negligible wind, and continued high demand late into the day, as solar generation dwindles. And as Overbye pointed out, the largest blackout in U.S. history (in 2004) happened on a regular run-of-the-mill afternoon.

What’s the Verdict?

As E&E News reported, despite severe storms causing some power outages in Oklahoma and East Texas, there have been no significant U.S. power outages due to heat or heightened demand from air conditioning. One entity, ISO New England Inc. who oversees the grid across six Northeastern states, reported a capacity deficiency due to transmission equipment failure during peak evening hours, but it didn't resort to rolling blackouts.

These scorching summer temperatures might just be a glimpse of what's to come. The World Meteorological Organization announced in May that due to climate change and the El Niño event, global temperatures are set to hit record levels in the next five years.

This heat could put an even greater strain on the electricity grid unless there's more smart grid innovations like higher adoption of energy efficiency tools to lower demand and investments in long-duration energy storage to help the grid avoid outages from weather disruptions.

Grid operators will need to integrate climate science and forecast for more abnormal situations. Furthermore, as summers get hotter, utilities will also have to help their customers adapt — while addressing the potential for outages in the process.

Related Posts