Once more with feeling: renewables did not lead to the Texas blackout
This past winter, a historic cold front left millions of Texans without electricity and heat for days. Wayne Christian, commissioner of the Texas Railroad Commission, wrote in the Wall Street Journal that the reason Texas was minutes away from total system collapse was the state’s “energy mix weighted towards unreliable sources of power,”–that is,wind and solar, and that the electricity grid in Texas needs to be “rebalanced with an emphasis on cheap, plentiful and reliable sources such as natural gas, coal, and nuclear.” This is a mischaracterization of the cascading failures that caused a breakdown of the state’s electricity system and a questionable suggestion for improving reliability.
Natural gas is the primary source of electricity in Texas, generating over 50 percent of the state’s power, followed by coal (19 percent). Wind and solar combined make up roughly 18 percent of the state’s electricity. Contrary to Mr. Christian’s claims, Texas’ electricity grid is in fact weighted towards fossil fuels. This is even more true during the winter months, with natural gas expected to provide nearly 70 percent of electricity capacity this past winter.
In a post-event analysis of the blackout, ERCOT, the independent system operator that manages the flow of power in Texas, found that fossil fuel sources made up a majority of forced outages, not renewables. Roughly 30,000 MW of “natural gas, coal, and nuclear generators (about half of what was expected to be online)” were already offline or suffered from a forced outage. Natural gas was severely impacted, with nearly 40 percent of natural gas capacity unavailable. Meanwhile solar and wind output “fluctuated roughly 4,000 MW to 5,000 MW below what was projected of them at a time,” but also regularly surpassed the 6,200 MW that was expected of them. If fossil fuels are compromised, specifically natural gas, the power system in Texas will underperform.
Would the high-renewables grid that Mr. Christian argues against have performed better? Wind and solar were not expected to provide significant power in ERCOT’s winter planning scenarios because they are highly variable and not an appropriate source of base load power. However, just because wind and solar resources on their own are ill-suited to serving large amounts of electricity load, does not mean that we cannot design a reliable and resilient electricity system with renewable energy being a dominant source of power.
The solutions to ensuring a grid dominated by variable generation resources is reliable are well understood, but not currently well integrated into our electricity systems. A net zero grid that relies primarily on renewable energy will need to be supported by firm low-carbon resources. That means Texas should invest in carbon capture, nuclear energy, and geothermal energy, while scaling their wind and solar resources. These renewable resources should also be coupled with storage (battery or pumped hydro) that charge when generation exceeds demand and can be used to smooth variability. Unlike other electricity markets, ERCOT is largely isolated from both the Eastern and Western Interconnections, a decision made to avoid federal regulation of ERCOT’s power markets. Texas could reconsider this stance, and invest in interregional transmission to help balance temporal variability (e.g. wind is often strongest at night and solar in the day) as well as geographic variability from extreme weather (e.g. sharing east or west coast resources in a future midwest storm scenario).
Texas should also take steps to improve the resiliency of its power grid, and that means preparing and insuring against unexpected weather events. Almost every source of power, from renewables to thermal power sources, were made obsolete by the winter storm in Texas. (Hydropower was the only source not to underperform, but provides very little percentage of Texas’ generation). Most of Texas’ energy infrastructure is not built to operate in extremely low temperatures, and the state must take active measures to weatherize its infrastructure. As Jesse Jenkins, professor and energy systems engineer at Princeton suggested in his New York Times op-ed, natural gas pipelines can be buried underground to protect them against colder surface temperatures, wind turbines can be constructed with heaters to melt ice off their blades, and sensors on power plants can be built to operate in freezing temperatures. These, of course, are costly measures to implement, but worthwhile considerations for grid operators and planners as they design electricity systems that need to operate in increasingly unpredictable climates.
The need to decarbonize the energy sector highlights the final component that Mr. Christian did not address in his piece: carbon. Mr. Christian criticizes the incentive differences between renewables and fossil fuels over the past decade, but he failed to note the implicit subsidies coal and natural gas experience in a system that does not price carbon. In a 2020 analysis of energy costs that considers subsidies and emissions, Lazard finds that a carbon price of $20-$40/ton of CO2 would make unsubsidized onshore wind and utility-scale solar competitive with conventional fossil fuel power sources.
Mr. Christian is right, in saying that the grid must have reliable sources for baseload generation. He is wrong, however, in thinking that a grid with high levels of renewable energy generation cannot be relied upon to meet the energy demands of the 21st century. Halting climate change requires shifting the economy away from carbon emitting generation, and doing so requires careful consideration of the technology and system needs that must accompany a low-carbon electricity sector.
Photo by Rabih Shasha on Unsplash