Tornadoes and More: What Spring Can Bring to the Power Grid
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The storm and tornado outbreak that recently barreled through the US Midwest, South and Mid-Atlantic was a devastating reminder of how much danger spring can deliver, despite it being the “milder” season compared to summer and winter.
Danger season is approaching, and the country is starting to see the impacts.
The event killed at least 32 people across seven states. The National Weather Service is still tallying up the number of confirmed tornadoes, which has already passed 100. Communities coping with tragedy are assessing the damage, which so far includes at least 72 destroyed homes in one Tennessee county alone, and dozens more homes elsewhere.
On Saturday, April 1–the day after the storm struck–there were 1.1 million US utility customers without power. On Monday morning, April 3, there were still more than 80,000 customers in the dark, according to PowerOutage.us. The storm system brought disruptions to both distribution grids–those networks of local power lines you generally see running overhead to buildings–as well as the larger transmission grid in the Midwest, which is far less common than distribution-level issues.
While we don’t yet have a lot of granular details about this latest storm’s grid impacts, it’s worth going through what else the country might be in for this spring, as well as in future springs. Moreover, there are steps policymakers can take to prepare for these spring weather phenomena and bolster the reliability and resilience of the US power system.
Heightened flood risk
The National Oceanic Atmospheric Administration (NOAA) said in a recent outlook that about 44 percent of the United States is at risk of floods this spring, equating to about 146 million people. This includes most of the eastern half of the country, the federal agency said.
The agency also sees “major” flood risk potential in some parts of the Upper Mississippi River Basin, and relatively higher risk in the Sierra Nevada region, due in part to a historic snowpack in California.
Multiple components of the power system can be affected by spring floods.
Power lines –Floods can saturate soil and make trees more likely to uproot and fall onto power lines. This has been contributing to power outages during California’s recent heavy storms–called atmospheric rivers–that started over the winter. In other regions, soil moisture has even been used as a predictor of where power outages will occur due to hurricanes, so that utility companies are better prepared to send line repair crews to the right areas. Hurricanes are primarily a summer and fall phenomenon, so for now, during spring, they are less of a concern.
Fuel transport – Spring floods can hinder the transportation of fuels like coal. While it is a heavily polluting fossil fuel that is set to continue declining as a fuel source for US electricity generation over the next decade, coal still accounted for roughly 20 percent of the country’s generation in 2022.
About 70 percent of US coal is transported at least part of the way by trains. The rail infrastructure to transport coal from the Powder River Basin in Montana and Wyoming–the country’s primary coal source–was proven to be vulnerable to extreme floods in the spring of 2011, and even more extreme floods in the spring of 2019. The 2019 floods’ disruptions of coal shipments to power plants via rail persisted for months and into the summertime, also affecting river shipments of coal by barge. In June 2019, hundreds of barges were stalled in the Mississippi River, through which millions of tons of the fossil fuel are normally transported.
Power plants –Power plants themselves can also be at risk of flooding, since most of them are sited near a source of water that is used to create steam to spin the plants’ turbines. Most US fossil fuel generating capacity from sources like methane gas and coal utilizes steam to generate electricity.
However, much of the attention paid to the flood risk of power plant sites has centered on nuclear plants, which also require a water source for the creation of steam, as well as for keeping the plant cool in an emergency. To name a notable flood example here in the United States–both visually and substantively–in 2011, the Fort Calhoun nuclear plant in Nebraska was completely surrounded by water due to late-spring flooding along the Missouri River. This sparked a lot of concerns because it was just a few months after the March 2011 meltdown of the Fukushima Daiichi nuclear plant in Japan. The public was thankfully not harmed by the Nebraska incident, but this was unfortunately not an isolated incident in terms of flood risks posed to the US nuclear power fleet.
Spring in a warming world means a broadened focus
The link between climate change and tornado activity is an active area of research. There is evidence of a shift in terms of where tornadoes occur, with a decrease in tornado occurrences in the central and southern Great Plains and an increase in parts of the Midwest and Southeast since 1979. Recent research also suggests that the risk of US tornados could increase in a warming world, with a higher risk in late winter and early spring, and a decrease in late summer and early fall.
The link to climate change is clearer, however, with floods. As my colleague Shana Udvardy explained in a blog post last month on NOAA’s spring outlook, a warming world due to human-caused climate change brings more water vapor and moisture into the air due to higher evaporation rates and an increase in the amount of water that the atmosphere can hold. This effect has been increasing the frequency and intensity of rainfall in some parts of the country, and scientists expect this trend to continue.
Since 1958, the amount of rain pouring down during the heaviest events has risen in every region of the lower 48 US states. The largest changes have been a 55 percent increase in the Northeast and a 42 percent increase in the Midwest.
So, what does this mean for the power system?
The focus of grid planning has traditionally been on meeting summer energy needs, and increasingly winter needs as well. This is ultimately for good reason because those two seasons trigger the highest energy demand. But that focus may need to be broadened.
Take, for example, the Northeast and the Midwest—the two regions that have experienced the highest increases in rainfall. These also happen to be two regions of the country that have been concerned in recent years about potential power shortfalls, primarily in the winter for the Northeast and summer for the Midwest.
As climate change brings more extreme weather events during more parts of the year, policymakers should take measures to prevent or mitigate the damage to the power system—and the resulting harm to communities—that can be brought by weather phenomena of all seasons, including spring.
Let’s make the grid more resilient in spring months
Thankfully, many such measures to make power grids more resilient each spring exist already.
Harden the power system – “Hardening” is a fairly wide umbrella term that can include everything from adequately trimming trees around power lines, to installing barriers around critical buildings at power plants so that they are better protected from floods, which helped reduce the safety risks at the Fort Calhoun plant in 2011. While there isn’t a power line design that is completely immune to being knocked out by high winds during storms, much less tornadoes, targeted hardening of the country’s aging grid can still greatly improve overall grid resilience and reduce the frequency and duration of outages, so that utility customers aren’t left in the dark for days or even weeks.
Reduce reliance on water- and fuel-dependent energy sources – However, hardening won’t be enough of a solution by itself. Diversifying the country’s power system away from large, thermal power plants that require fuel and water to operate–like coal- and gas-fired plants–can also make the grid more resilient to spring impacts like floods and other extreme weather. Clean energy sources like wind power and solar photovoltaic power are fueled at no cost by the wind and the sun, and don’t need to be sited near water sources. When combined with energy storage and increased transmission grid capacity, these two renewable energy sources could reliably meet 60 to 80% of the country’s electricity needs by 2035, while also delivering benefits that far exceed the costs of transitioning the power system, according to modeling by the National Renewable Energy Lab (NREL). Increasing the adoption of other solutions like microgrids and flexible demand can also boost grid resilience while integrating higher amounts of renewables at the same time.
Address climate change by reducing greenhouse gas emissions – Luckily, this has a great amount of overlap with the above strategy. Reducing reliance on thermal power plants–specifically fossil-fueled ones like coal and gas plants–helps to address climate change by reducing the greenhouse gas emissions of the power sector, which is second only to the transportation sector in terms of US emissions. The country can stave off the worst impacts of climate change and limit the increase in extreme weather events by drastically cutting the use of fossil fuels to meet electricity needs. This will deliver not only climate-related benefits, but also loads of other public health benefits like those related to air quality, as NREL discussed in its grid study and I discussed in my blog last month.
The country can be more prepared for the dangers of spring. Doing so will allow us to better enjoy the sunnier and longer days of this season. I’m definitely biased as an energy analyst, but I think the grid is a great place to start for better preparing for those dangers.