Projected changes in U.S. electricity expenditures by 2080–2099 compared to today, assuming continued increases in carbon dioxide emissions from fossil fuels. For each county, the fill color indicates the median percentage change in projected spending on electricity as a result of rising global temperatures. The outline color indicates the level of certainty of the projections. Black outlines indicate projections with the greatest confidence; no outline indicates a bit less confidence. Projections for counties with thin white outlines have the lowest confidence.
Annual average temperature over the contiguous United States has increased over the last century and scientists are highly confident it will continue increasing into the future. Extreme high temperatures are projected to increase even more than average temperatures. Heat waves are projected to become more intense and cold waves less intense. The number of days above 90°F is projected to rise while the number of days below freezing is projected to decline.
Rising energy costs
In future decades, warmer winters will decrease the need for heating, reducing energy consumption. Conversely, hotter summers will increase demand for cooling, increasing the amount of energy consumed. The energy saved during warmer winters is not expected to offset increases in consumption during hotter summers. Therefore, most regions can expect a net increase in energy consumption. As a result of higher temperatures, economists estimate increases in net energy costs for all but the coldest regions of the contiguous United States.
Changing energy sources
The mix of energy sources used in each region may also change with increased temperatures. Winter heating is powered by a mixture of electricity, fuel oil, and natural gas, whereas summer cooling is powered by electricity. The expected consequence of this situation is reduced demand for fuel oil and natural gas and increased demand for electricity. Using wind and solar to generate electricity to meet this demand may shift consumption of fossil fuels to more renewable sources of energy.
Effects on energy infrastructure
Increased energy consumption may strain energy infrastructure, especially during periods of peak energy demand. For instance, on days when temperature exceeds 95°F, demand for electricity may exceed the capacity of energy-generating facilities and the electrical grid. Disruptions in service—including the potential for widespread blackouts—may result. Increased instances of peak demand for electricity could also affect production and transmission costs, ultimately increasing costs for consumers.
Other factors in energy consumption
Changes in energy consumption also depend on factors other than climate change. Population change, economic growth, and international energy pricing all affect energy consumption patterns. Adaptive responses—such as diversifying supply chains, improving electrical grid reliability, adding more electricity-generating facilities, increasing transmission capacity between regions, energy conservation, and increasing reliance on renewable sources of energy—could reduce the impacts of climate change and extreme weather on the energy system.
The preceding text is excerpted and abridged from Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II Chapter 2: Our Changing Planet and Chapter 4: Energy Supply, Delivery, and Demand, and