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Southern Heat Strains Power Generation

The heat this summer has been extraordinarily intense in many Central and Southern states, and triple-digit temperatures continue to roast parts of Texas, Oklahoma, and Arkansas. For example, Dallas, Texas is closing in on its record for the longest streak of 100°F days, and similar milestones have already been reached in other parts of the Lone Star state. At 88.9°F, the average temperature in Oklahoma during the month of July set a new record for the all-time warmest calendar month for any state in the US during any month. 

Perhaps not surprisingly, this unrelenting warmth is putting a strain on power generation in several areas. During warm weather like this, the demand for electricity peaks with the highest temperatures, as people rely more on air conditioning to keep cool. In order to meet the extra demand during hot weather, power companies typically have to boost their electricity output.

The cruel twist is that, by affecting power plant cooling systems, the persistent heat can also hamstring electricity generation, and this has played out during the past few weeks in parts of the South.

Last week, the Tennessee Valley Authority was forced to cut power generation in half at their Browns Ferry nuclear power plant near Athens, Alabama.

A few months back, I wrote about the threat heat waves pose for nuclear power plants, and Browns Ferry in particular. Nuclear plants draw in water from nearby rivers or lakes for cooling purposes, but they face environmental restrictions on how warm the water can be that they discharge back into the river (coal and natural gas-powered plants also draw water for cooling, but not as much heat gets transferred to the water, so there typically isn’t as much risk for these operations during heat waves).

Last week, when the Tennessee River temperature rose above 90 degrees, the TVA could no longer release the amount of water needed to run the plant at full capacity.

After facing a similar problem during an August heat wave last summer, the TVA began constructing an additional cooling tower at Browns Ferry. The extra cooling tower will help reduce their reliance on river water for cooling, so during heat waves they won’t have to cut power so much. However, storms earlier this spring have slowed construction on the cooling tower, reports the Chattanooga Times Free Press.

In Texas, the severe heat has also put pressure on the electrical grid. After cities like Houston, Dallas, and Austin all kicked off August with five consecutive days of triple-digit heat, residents faced threats of rolling blackouts. According to Trip Doggett of the Electricity Reliability Council of Texas, the Texas grid has been further strained by power plant outages. As Doggett told the Dallas Morning News, at least one power plant has had to reduce its output after the water it uses for cooling became too warm, possibly because Texas' record drought had lowered water levels.

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