Extreme heat and drought is likely to have a range of impacts on U.S. West Coast grids, from increased power prices to widespread blackouts, according to two recent studies.
The studies, led by a North Carolina State University researcher, offer previews of what power producers and customers on the West Coast can expect under two potential future scenarios: one with extreme heat caused by climate change that strains power supplies, and one where the power grid shifts to renewables while the climate follows more historic trends.
"The impacts of climate change and extreme weather events on the grid, mostly in the form of drought and heatwaves, are going to get worse under climate change," Jordan Kern, assistant professor of forestry and environment resources at N.C. State said in a Jan. 5 statement. "Even as the West Coast grid moves away from fossil fuels toward wind and solar, these extreme weather events will still impact system reliability and the price of power."
The studies, which aim to project future power supply and demand under each scenario, were published in December in the journal, "Earth's Future," under the titles "The effects of climate change on interregional electricity market dynamics on the U.S. West Coast" and "Technology pathways could help drive the U.S. West Coast grid's exposure to hydrometeorological uncertainty."
For the first study, researchers used computer models to simulate the effects of climate change on California and the Pacific Northwest, which have historically shared power. Researchers evaluated the price of power and grid reliability under 11 climate scenarios from 2030 to 2060 using models of how the climate may change under a worst-case scenario of fossil-fuel emissions, along with less severe scenarios.
Blackout risk was highest in summer and early fall, researchers determined, largely from extreme heat in California that pushed electricity demand higher. Researchers projected power shortfalls in all but one of the scenarios they modeled. Those power shortfalls would still be relatively rare under the modeled scenarios, and the maximum blackout under the worst-case scenario was about 72 hours of West Coast-wide power supply shortages.
"As it gets hotter and hotter and hotter, and demand for electricity gets higher, we expect the grid to fail," Kern said in a statement. "If, and that's a big 'if,' historic exchanges of electricity continue, and California has a high demand for electricity because of heat, it could cause the Pacific Northwest to run out of electricity, as they won't be able to meet their own demand."
The Pacific Northwest could face its own direct power shortfalls because of limited hydropower supplies, researchers found. Snow serves as stored hydropower, so reductions in snow or changes in the timing of snowmelt could significantly reduce available power in warmer months when the grid is already under stress. Even small decreases in streamflow in September, for example, could cause shortfall events in the area, though researchers projected shortfall events in the Pacific Northwest alone to be rare.
The second study examined how climate change could affect power prices through 2050 with more renewables added to the grid, assuming natural gas plants are still used as backup generation. Under the worst case, where climate change affects power supply and demand in both California and the Pacific Northwest, researchers said they expected more hours in which the wholesale price of electricity reaches the cap of $1,000 MW/hour in California, particularly in the hottest months.
Even with added renewables, researchers found that extreme heat and drought conditions would still increase energy prices, with relatively good years driven by mild temperatures and higher streamflow. Increased wind energy in California led to the state's lowest prices, according to the study. In the Pacific Northwest, the models with the highest levels of both wind and solar had the lowest energy costs. Electricity supply shortfalls were more common under the model that included the greatest demand for electric vehicles.
"Our key finding was that as the grid decarbonizes, you are still going to be left with that vulnerability to water and heat," Kern said. "This is a system that can't run away from that."
