Looking back at the great Texas power outage of 2021
At a glance
One of the most powerful lessons learned from the Texas power outage of February 2021 was that the State's grid needs to stand up to more extreme weather events. But how "extreme" is that? How do power generators determine reasonable reliability measures versus over-engineering ones?
The Texas Power Grid is unique in that it is managed by the Electric Reliability Council of Texas (ERCOT) and is a free market. This incentivizes some individual power generators and utility owners to focus on maintaining a positive balance sheet for their investors instead of adding non-mandatory resiliency measures to prepare for weather events that have a very low probability of happening in a given year. (For example, a "100 Year Event" has a 1% chance of happening in a given year).
For this to change, stakeholders in Texas need to push for consistency across the State's power generators regarding reliability measures. Enforced by regulators such as the Public Utilities Commission of Texas, these measures can help maintain the free market and keep reliability high.
What factors caused the power outage?
To understand why increased reliability matters, we need to understand some of the unique aspects of Texas's power generation. The State's power demand has grown by about 20% in the past decade due to Texas's explosive population and industrial growth; however, ERCOT has managed to keep up with this rise in demand.
So why did demand exceed supply in the February 2021 storm? Part of the reason might stem from the fact that power demand is highest in Texas in the summer. So, it's reasonable for power generators to do their routine maintenance and upgrades during their off-season - winter. We may find that having equipment down for scheduled maintenance was one factor reducing power availability during the freeze event.
Another Texas-specific reason comes from so much of its electrical power being generated at gas-fired power plants. Looking back at a similar storm in 2011, one of the leading causes of power outages was that many wellheads for the natural gas supply froze. This may be an influential factor in 2021 too.
The cold weather also interrupted the gas supply because it often contains moisture, which froze in the pipes and wellheads, causing constrictions and blockages. Below-freezing temperatures also impacted the water pipes carrying boiler water for electrical power generation.
These impacts on the gas supply may have been even more severe in 2021 than in 2011. One reason is that in the decade since 2011, many of the coal-fired plants in Texas have shut down. This means that even with the increase in solar and wind power over the past decade, Texas' natural gas footprint, as a percentage of generation, is bigger now than it was 10 years ago. As a result, the State depends even more on gas-fired power plants.
Would better power-sharing agreements have helped?
The technology that allows power-sharing is the obstacle here. Each of the three grids in North America – Eastern, Western and Texas – operates on frequencies that may not match the other two. There are connections between the grids, but the amount of power that can pass between them is limited by the need to pass the energy through equipment that essentially changes it to match the timing of the grid it's going to. Adding new or upgrading this type of equipment is very expensive and it will still have a limited amount of power that can be passed through.
The Southwest Power Pool (SPP) is the grid operator (manager of the grid and wholesale market) for a large portion of the middle part of the U.S. and is ERCOT's neighbor to the north. ERCOT and the SPP can share power through two of the special interconnections that deal with frequency. So would upgrading this equipment or adding more interconnections have solved the problem?
Probably not. The winter storm impacting Texas didn't just hit Texas. It also hit the states to the north, where the SPP supplies power. The SPP had its own problems with supply during that storm, and so they directed their member utilities to implement controlled temporary interruptions of service, or rolling blackouts. The SPP was not in a position to give much help to Texas.
What steps can be taken to boost the reliability of the Texas power supply?
With the competitive market in Texas, regulators play an important role: providing a level playing field. There aren't many incentives for independent generators to spend large amounts on improving reliability, increasing their costs if their competitors aren't spending that money.
This means that regulations will need to be prescriptive – setting out steps that all power generators have to take to be treated equally.
For example, during the 2011 storm, there were high winds – and wind tends to speed up the thermal loss so that water pipes and gas wellheads freeze faster. But if there are requirements to building shelters around installations vulnerable to freezing, those assets are protected, and their reliability improves.
Regulatory authorities can also play a part in improving requirements around hiring and training.
Power utilities will need qualified Reliability professionals to institute procedures and enforce them. If all power generators are required to take the same steps, none is at a financial disadvantage, and the result is higher reliability in the electrical supply. This would reflect in the rates paid by consumers. But if the expense is spread out among various suppliers, that would likely provide low and consistent cost increases spread out among all consumers.
These are some potential changes to regulations for all forms of power generation, including renewables, that could improve the reliability of the gas supply in Texas and help avoid a repeat of the hardships, economic cost and loss of life caused by the Great Texas Storm of February 2021.
The result is greater power supply reliability, helping keep Texas a great place to live and work.