Climate Change Threatens Electric Grid Reliability in the Southeast

The Tennessee Valley Authority's Browns Ferry Nuclear Plant near Athens, Alabama, is seen in March 2008.

The Southeast region of the United States boasts diverse landscapes, from the coasts to the Appalachian Mountains to the Everglades of Florida. The Southeast is already experiencing the effects of climate change, including sea level rise, extreme storms, heat waves, and drought. These impacts pose a great risk to states’ infrastructure, including the electricity grid, and threaten the region’s economy and quality of life.

In August, the Environmental Protection Agency, or EPA, finalized its Clean Power Plan to cut carbon pollution from the nation’s power plants. Some opponents of the rule pushed back, claiming inaccurately that it would threaten electric grid reliability. In reality, the final Clean Power Plan will target a significant threat to grid reliability—climate change and the effects of it—by reducing carbon emissions from the power sector by 32 percent from 2005 levels by 2030.

Recent analysis from the Department of Energy, or DOE, identifies extreme weather as a “leading environmental risk” to the electric grid, noting that transmission, storage, and distribution infrastructure is “vulnerable to many natural phenomena,” such as “hurricanes, earthquakes, drought, wildfires, flooding, and extreme temperatures.” When, as scientists predict, these events become more frequent and intense, our efforts to tackle carbon emissions—the root cause of climate change—must intensify as well.

Extreme storms and sea level rise

Extreme storms can knock down transmission and distribution lines and are one of the greatest threats to grid reliability in the Southeast. Already, grid outages attributable to weather-related events are on the rise, costing the U.S. economy an estimated $20 billion to $55 billion annually. In 2005, for example, Hurricanes Rita and Katrina knocked down more than 85,000 poles and damaged more than 800 substations, as well as thousands of transmission and distribution lines. At the peak of outages, the hurricanes left more than 3.5 million people without power in the Gulf Coast. Hurricane Jeanne, which struck Florida in 2004, damaged power lines and forced power plants to shut down throughout the state. As a result, almost 2.6 million customers across Florida lost power, according to a DOE report.

Extreme storms also threaten upstream components of the energy sector by damaging infrastructure along the supply chain. Hurricanes Katrina and Rita destroyed or damaged more than 150 offshore platforms and 500 pipeline segments on the Gulf Coast. The Gulf’s offshore production of oil and gas was shut down for weeks; nine months later, production of oil and natural gas was still down by 22 percent and 13 percent, respectively.

On the Atlantic and Gulf coasts, energy infrastructure is also increasingly vulnerable to erosion and flooding amplified by sea level rise and land subsidence—the collapsing of land into itself due to groundwater loss, shifting plates, or mineral extraction. Global sea levels have risen roughly eight inches since the late 1880s and are expected to rise another one to four feet by the end of this century. In the coastal Southeast—where precipitation and extreme storm events are increasing in frequency and strength and where land subsidence is prevalent—sea level rise combines with these conditions, increasing damage to coastal communities and infrastructure. According to the DOE, if worst-case predictions about sea level rise come to pass, the number of electricity substations in the Gulf of Mexico exposed to storm surge from Category 1 hurricanes could increase from 255 to 337 by 2030 and to 400 by 2050. Stronger hurricanes would exacerbate these risks.

Heat waves

Extremely high temperatures put pressure on the electricity grid. According to the DOE, the Southeast should expect steep growth in demand for electricity to meet cooling needs in light of increasing heat waves and humidity. The National Climate Assessment—a report on current and future impacts of climate change across the United States that is broken down by region and sector—predicts that many states in the Southeast, particularly Florida, Louisiana, Mississippi, Alabama, and Georgia, will experience significantly more days with temperatures reaching more than 95 degrees.

In addition to straining the grid, higher temperatures make it harder for individual power plants to operate. Nuclear power plants and large, fossil fuel-fired power plants often require water for cooling. When water temperatures rise too much, generating capacity is diminished. For example, a Tennessee Valley Authority nuclear power plant in Athens, Alabama, was forced to reduce production because the Tennessee River water temperature was too high to receive discharged water after it had been used to cool the plant. Continued energy production at normal levels would have put the river at risk of ecological harm, and the Tennessee Valley Authority was forced to reduce the energy production of its reactors for almost two months. No outages occurred, but replacement power cost the utility an estimated $50 million.

As of 2014, power plant generating capacity in the Southeast could pro­duce 32 percent of the United States’ electricity. The region uses about 27 percent of total energy in the United States—a higher proportion than any other region. Demand is only expected to increase as the need for cooling rises with temperatures; the increased demand could stress generating capacity and increase energy costs, disproportionately affecting vulnerable, low-income, elderly, and native communities.

Drought

Drought often goes hand in hand with increased heat. According to the National Climate Assessment, scientists expect reduced water availability across the Southeast as temperatures rise and evaporation increases. Water availability is projected to decline most in the western part of the Southeast region, including Arkansas and northern Louisiana.

The Apalachicola-Chattahoochee-Flint River Basin in Georgia is one such area already under stress from low water levels and competing uses for a limited supply of water. The basin crosses into Alabama and Florida and spreads along the entire length of Georgia. While the basin provides communities with a source of fresh drinking water, it also provides water for hydroelectric power generation and power plant cooling, making it a critical component of energy generation in the area. Future climate change projections anticipate more severe and frequent water shortages, which would further deplete the basin.

Florida is currently in the midst of a drought, though many residents remain unaware. However, in some areas of southern Florida, residents have been asked to conserve water or increase use of reclaimed water. Precipitation levels remain 10 inches to 16 inches below average for this time of year in many parts of southern Florida, and the abnormally dry conditions increase the risk of wildfires, which have already scorched more than 72,000 acres across the state since the beginning of 2015. Like other regions of the country, wildfires can cause immense damage to the electricity transmission and distribution infrastructure, threatening grid reliability.

Conclusion

Through the Clean Power Plan and other measures, the EPA is taking action to reduce carbon pollution—the driving force behind the changing climate. Climate change has already affected the Southeast, evidenced by the damage that extreme storms, heat waves, and drought have wrought on communities and infrastructure. These climate change effects are the real threat to electric grid reliability, and the DOE has made several recommendations on how to improve energy infrastructure in the United States. Congress and state governors should work to implement these recommendations and should support the EPA’s measures to reduce carbon emissions and fortify the country’s electric grid against the effects of climate change.

Myriam Alexander-Kearns is the Research Associate for the Energy Policy team at the Center for American Progress.