Rolling blackouts in California and Texas: grid resiliency going forward
Rolling blackouts in California and Texas: grid resiliency going forward
Introduction California suffered significant power outages during periods of extreme heat at least three times between October 2019 and October 2020. Winter storms blew through Texas in February 2021, resulting in widespread power outages across the state, leaving over 4.5 million homes without power.1 The crises in California and Texas are different, both in scale and severity; one faced fire, the other an ice storm. But the power outages show that neither state is prepared to provide continuous power in extreme weather conditions.2
What caused these events, and how might they have been prevented? Was the nation’s transition to renewable energy responsible for these outages? Renewables did play a part in each event; in California, solar panels couldn’t meet demand after the sun set or when smoke from wildfires prevented sunlight from reaching the panels, while in Texas some wind turbines shut down due to the extreme cold. However, each case involved a variety of problems beyond solar and wind power, including poor planning failures, inadequate design and maintenance, structural constraints and trouble with gas-fired power plants.3 These events could have been mitigated, if not completely avoided, with better planning. Increased reliance on renewable energy played a part in both events, but this contribution ultimately was minimal relative to other factors.
California power outages 2019 and 2020 California’s October 2019 power outages were public safety power shutoff (PSPS) events, involving massive preemptive power shutoffs that initiated in some 30 counties in October and November 2019. Pacific Gas and Electric Company (PG&E), Southern California Edison (SCE), and San Diego Gas & Electric (SDG&E) combined to shut off power to prevent wildfires from being started by electrical equipment (primarily transmission & distribution lines and substations) during strong, dry winds. The shutoffs initially affected around 800,000 customers, or about 2.5 million people4 .
The rolling blackouts of August 14-15, 2020 were different, caused by a myriad of factors not involving load-shedding to prevent forest fires5 . The western United States saw record-breaking temperatures across the West during periods of high demand, perhaps exacerbated by COVID-19 restrictions confining many people to their homes. Couple that with the loss of a 475 MW gas-fired power plant, and an out-of-service 750-megawatt unit not being available, and CAISO (California’s grid controller/operator) was forced to shed load. There were some typical fluctuations in available renewable power, but nothing unexpected. With a key baseload plant down, ultimately there wasn’t enough power generation to meet the increased load. Part of the shortage was due to the fact that some baseload power had been retired and replacement capacity was not yet available – a result of poor planning, and California didn’t line up the right power sources to keep the lights on after sundown. Fewer than half a million homes and businesses lost power for between 15 minutes and 2½ hours on August 14, with another 321,000 customers without power the following evening for up to 90 minutes.6
An autumn heatwave, along with hot, dry “Diablo” wind gusts up to 55 mph, led PG&E to shutoff power to over 50,000 customers in Northern California as a preventive measure to prevent forest fires. This was the third time in less than two months that PG&E cut power, aiming to prevent power lines from sparking wildfires if they were fouled or blown down by the winds. PG&E equipment had previously been found at fault in two of the deadliest wildfires in California’s recent history, including the 2018 blaze that destroyed much of the town of Paradise and killed 85 people.7
In summary, the October 2020 and October 2021 rolling blackouts were undertaken to mitigate the risk of forest fires. The August 2021 outage was caused by inadequate generation availability; certainly, the transition to renewables plays a part in all of these outages, but it would be a stretch to consider this transition to be the cause of these events. Better grid maintenance, the provision of more on-demand power, transitioning from overhead to expensive underground lines and moving towards distributed generation and microgrids (see Jamie Markos’ article elsewhere in this Review) would all help lessen the impact of future events.
These events should not have surprised anyone - PG&E announced in October of 2019 that shutoffs would continue for 10 years before they can start to reduce significantly.8
Texas freeze – February 2021 In February 2021, a polar vortex brought intense cold to a majority of the American heartland, freezing much of Texas’ natural gas supplies. What gas supplies were available were sent to homes rather than to power suppliers, leaving no gas to fuel the power plants. Consequently, Texas sustained massive blackouts as much of its generating capacity was knocked offline. Massive outages impacted more than four million residents, including Houston, Austin and elsewhere in the state9 .
While unusual, this event was not unprecedented; ten years earlier in February 2011, ERCOT, the manager of the state’s power grid, was forced to implement rolling blackouts during a similar freak round of cold weather and there were also similar issues in 1989. In the 2011 and 2021 events, some wind turbines in West Texas were unable to operate, and key natural gas pipelines froze. After freeze events in 1989 and 2011, measures were recommended to winterize pipelines and wind turbines to better cope with cold temperatures in the future; however, this guidance was largely ignored. When wells froze10, power outages made it impossible to pump the gas; technologies exist to winterize equipment to withstand extreme cold, and such measures are implemented in northern states and Canada. However, such measures are expensive and not undertaken in the deregulated Texas electricity market.
Additionally, as most of the state operates its grid separately from the rest of the western region (largely to avoid federal regulations), Texas wasn’t able to easily import power from neighboring states.11 Texas should learn from El Paso, which maintains interstate grid ties not with ERCOT but with the Western interconnect. El Paso was spared 2020 power outages; the rest of Texas should similarly tie into regional grids. In 2014, another polar vortex interrupted natural gas supplies to the East Coast, causing power plants to stop operating. As a result of that event, ISO-New England and PJM implemented stringent capacity/reliability markets, including performance incentives and penalties and giving enforcement power to the grid operators; consequently, additional reliability has since been built into the grid.
Many believe that until the electric market in Texas is similarly changed to pay for reliability and capacity, with performance incentives and penalties and giving enforcement power to grid operators, widescale power outages will likely occur again.
Conclusion An analysis12 of Department of Energy data published in September 2020 found weather-related power outages are up by 67% since 2000. Until these states do more to prepare their grids for extreme weather events and provide adequate standby power generation on demand, we will see more events like these in coming years.
In California, increased use of battery storage, strategically burying some power lines and installing microgrids are measures that can provide some help. This will result in the provision of on-demand power when needed, reducing the threat of wildfire so sections of the grid need not be shutdown. Another measure would be supplying localized power so that the threat of wildfires elsewhere will not impact local power supply.In Texas, winterization measures and contingent power suppliers would help. According to ERCOT, reserve capacity estimates are currently 15.5%, which ERCOT intends to increase to 25% by 2025. A much larger reserve margin and/or significantly improved generating reliability is needed13. Giving enforcement power to the grid operator to implement a capacity marketplace with performance incentives and penalties to assure reliability and adequate spare generation would be a great help.
All of this requires significant investment to assure the grid resiliency we expect. Hopefully, such measures will find their way into President Biden’s clean energy plan.
