Climate Change Threatens Electric Grid Reliability in the Midwest and Great Plains

Floodwaters from the Missouri River surround the Fort Calhoun nuclear station in Nebraska, June 2011.

The Midwest and Great Plains regions of the United States contain diverse states with very different economies. Sources of power generation in these regions are just as varied, ranging from large fossil fuel plants to renewable sources and nuclear power. The Mississippi and Missouri Rivers, which run through and next to many states in these regions, provide large quantities of hydroelectric power. Meanwhile, the Midwest and Great Plains are already seeing the impacts of climate change, which threaten these power generation sources, as well as the regions’ transmission and distribution infrastructure.

The Environmental Protection Agency, or EPA, released the final Clean Power Plan on August 3, 2015. The final rule will reduce carbon emissions from the power sector 32 percent from 2005 levels by 2030; however, opponents of the plan have attempted to inaccurately paint it as a threat to grid reliability. The day after the EPA released the final rule, Kansas Gov. Sam Brownback (R) released a statement arguing that the final rule would have detrimental effects on electricity rates for consumers and bring grid reliability into question. Gov. Mike Pence (R) of Indiana was also quite vocal in his opposition to the final rule, referring to Indiana’s current use of coal-fired plants as the way to “low-cost, reliable energy.” In a similar vein, Sen. John Barrasso (R) of Wyoming warned in a press release that the rule will “undermine electric reliability.”

Critics of the final Clean Power Plan fail to recognize that the rule targets carbon emissions—a leading cause of climate change and the true threat to electric grid reliability. The Department of Energy, or DOE, acknowledges extreme weather as a “leading environmental risk” to multiple parts of the electric grid, including transmission, storage, and distribution systems. DOE notes that this infrastructure is “vulnerable to many natural phenomena,” such as “hurricanes, earthquakes, drought, wildfires, flooding, and extreme temperatures.” Scientists expect these events to become more frequent and intense as the climate continues to warm.

The Midwest and Great Plains states are already facing many of these impacts of climate change. In 2011, 11 of the 14 weather-related disasters in the United States that caused at least $1 billion in damage affected the Midwest. If left unchecked, climate change could stress the electricity grid in the Midwest and Great Plains by increasing the frequency and severity of extreme precipitation in some parts of the region and exacerbating drought in others.

Extreme precipitation and flooding

According to the National Climate Assessment, or NCA, heavy precipitation events will increase in intensity across the Midwest as global temperatures continue to rise. Precipitation in the Northern Great Plains is also expected to increase, and this pattern has already been observed in the area. In 2011, Montana and Wyoming experienced their wettest springs on record, with Nebraska and the Dakotas experiencing similarly high levels of rainfall.

Recent history shows that extreme precipitation can damage coal-fired, nuclear, and hydroelectric power plants and cause power outages for businesses and residents. Flooding in the Duluth, Minnesota, region in June 2012 fully submerged the Thomson Hydroelectric Station, shutting down all six of its generators. It took 28 months and an estimated $90 million in refurbishing costs to bring just one generator back online.

Large nuclear and fossil-fueled power plants need access to water for cooling; as a result, they are almost always located on or near waterways, making them particularly vulnerable to flooding. In 2011, heavy rains caused the Missouri River to rise, flooding the Fort Calhoun nuclear power station in Nebraska. Similarly, June 2008 floods in Iowa severely damaged the Sixth Street coal-fired plant in Cedar Rapids. Although the operating company, Alliant Energy, initially committed to repairing the plant, the company later decided to close and demolish it. The flood also shut down Alliant’s Prairie Creek coal-fired plant for more than six months, and it cost an estimated $152 million to bring the first boiler back online. It was another 13 months before the plant generated as much power as it did before the flood. A third coal-fired plant, the Sutherland Generating Station, was offline for two weeks due to damage to its coal unloading and handling system and the inundation of its coal yard.

In addition to flooding, strong storms can topple key infrastructure. Storms with heavy wind and rain knocked down electricity infrastructure in Kansas in early July 2015, disrupting power for residents. The storms dismantled 23 poles in Sunflower Electric Power Corp’s system. Victory Electric Cooperative in Dodge City, Kansas, lost transformers, power meters, and 42 distribution poles, and the storms brought down miles of wire.

Droughts

According to the NCA, climate change will intensify short-term droughts in most U.S. regions and contribute to longer-term droughts in several locations, including the southern Great Plains. Oklahoma, for example, can expect longer dry spells by the middle of this century. In fact, the state already faced severe drought conditions over the past few years, with some relief coming from higher-than-usual rainfall this summer.

Droughts stress the electric grid in several ways. During times of drought, low reservoir levels mean that less water is available for power generation in hydroelectric plants. Thermoelectric and nuclear power plants also may struggle to obtain the volumes of water needed for cooling.

In 2007 and 2008, coal-fired Laramie River Station in Wheatland, Wyoming, which uses water for cooling, had to draw on water from irrigation sources to avoid halting operations when water levels dropped too low. In 2012, operators of the Duane Arnold Energy Center, a nuclear power plant, had to dredge the Cedar River in Iowa to maintain access to enough water for operations.

Heat waves

As the climate continues to warm, Americans also will experience more frequent and intense heat waves, which will exacerbate droughts but also cause problems of their own. Heat waves increase demand for air conditioning during peak hours, which can strain the grid. In the Midwest, the ratio of electricity demand for heating to cooling is expected to shift as summers grow longer, heat waves become more frequent, and humidity rises. According to the NCA, by the middle of this century, demand for cooling in the Midwest is expected to increase more than 10 gigawatts—the equivalent of the output of five large power plants. This increase in demand will require at least $6 billion in energy infrastructure investments. The number of days hotter than 100°F is projected to double in the northern part of the Great Plains and quadruple in the southern part of the region by mid-century. In 2011, many locations in Oklahoma endured more than 100 days at temperatures of 100°F or higher.

Similar to drought, heat waves can also threaten power generation. Extreme heat makes electricity transmission infrastructure less efficient and increases the temperature of the water needed to cool power plants. According to the NCA, approximately 95 percent of the electricity generation infrastructure in the Midwest is vulnerable to efficiency loss under high-temperature conditions. The combination of drought and extreme heat can be especially detrimental to the power generation. In 2006, drought conditions and a heat wave warmed the Mississippi River, heating up intake water for nuclear plants in Minnesota and Illinois and affecting plant operations.

Conclusion

Climate change is the real threat to grid reliability, not the measures the EPA has taken to fight it by reducing carbon pollution from the power sector. As the climate continues to warm, the Midwest and Great Plains states will face more drought, heat waves, storm events, and flooding—all of which directly threaten the electric grid. In its Quadrennial Energy Review, the DOE made several recommendations for how to improve the resilience of the country’s energy infrastructure. Rather than fighting the Clean Power Plan and other climate action, members of Congress and state governors should review and implement these recommendations to ensure that America’s electricity grid remains reliable in the face of the impacts of climate change.

Myriam Alexander-Kearns is the Research Associate for the Energy Policy team at the Center for American Progress. Alison Cassady is the Center’s Director of Domestic Energy Policy.