The North American Reliability Corporation (NERC) recently released its 2024 summer reliability assessment. The report studied several regions of the country that are at risk for insufficient power in “above-normal conditions,” or when temperatures are particularly high. The good news from this report is that no grid regions were reported to be at “high [risk],” which would be the case if any area was at risk of being unable to meet demand under normal peak demand conditions. 

Nonetheless, a healthy grid should be able to absorb the added strain of a heat wave. This assessment is yet another reminder that large portions of the nation’s electrical grid remain vulnerable to temperature fluctuations.  

The report placed parts of the Midwest, Texas, California, the Southwest, and New England at elevated risk this summer. 

A few of these situations are especially notable:

The Midcontinent Independent System Operator, which covers much of the Midwest, is one of the grids at elevated risk. Reliability in above-normal conditions for this region will hinge in part on whether wind and solar production is as high as it’s projected to be. In particular, NERC asserts, “Wind generator performance during periods of high demand is a key factor in determining whether there is sufficient electricity supply on the system or if external (non-firm) supply assistance is required to maintain reliability.”  

New England is coming into the summer with less capacity than usual thanks to the retirement of two natural gas generating units at Mystic Generating Station at the end of this month, taking a combined 1400 MW capacity off the grid. According to the NERC reliability report, this closure “makes it more likely that ISO New England will need to resort to operating procedures for obtaining resources or non-firm supplies from neighboring areas during periods of above-normal peak demand or low-resource conditions.” In other words, this closure makes New England more reliant on its neighbors for power in times of grid stress. 

According to the report, the Texas grid is at elevated risk. It explains one major reason for this: “As a result of continued vigorous growth in both loads and solar and wind resources, there is a risk of emergency conditions in the summer evening hours when solar generation begins to ramp down.” One of the major challenges for the state this summer will be supplying enough electricity during the time of day when demand rises, around sunset when people get home from work, and solar resources go offline (the so-called “duck curve”).

Grid reliability (or unreliability) is the result of many factors. One of the largest changes in recent years has been subsidizing and mandating unreliable sources while reliable sources, especially natural gas and nuclear, are pushed off the grid. 

The confluence of these factors results in less reliable and more vulnerable electricity supplies and imperils a resource that modern life heavily relies on.