Cold, hard lessons from Texas-sized storms
“Yes, extreme weather events will always challenge the system, but no we cannot just accept that as a foregone conclusion. We have to plan for these risks.” – TVA PRESIDENT JEFF LYASH
America’s biggest public provider of electricity plans to study last week’s power outages in Texas to see what lessons should be learned and applied to avoid the power outages and rolling blackouts that left about 4 million Texans in the dark, most without heat, during a winter storm.
But the Tennessee Valley Authority says it has already implemented many of the cold weather and backup power protections that were missing in the competitive Texas electricity market where rolling power blackouts froze water pipes and natural gas plants, cut off power and led to at least 40 deaths and millions of dollars of damages.
Aaron Paul Melda, senior vice president of transmission and power supply at TVA, said the federal utility boosted its winter reserve margins after frigid winter temperatures in previous years boosted power demand. Unlike Texas, TVA also has built its gas-fired generators with more cold-weather protections to ensure they continue to operate in subfreezing temperatures.
“Our natural gas plants are designed to withstand temperatures down to zero degrees
[Fahrenheit] and if we see below-zero temperatures in our area, which would be quite an anomaly, we have additional measures and equipment at our plants to put in critical areas to keep our plants operating in even colder weather,” Melda said. “We also work to ensure high reliability with a diverse fleet so that we have the ability to shift power sources as weather and demand dictates.”
In Texas, most of the gas lines and power plants are not insulated and are more exposed to cold weather, which can limit or even freeze their operations as happened at some plants last week.
According to the U.S. Department of Energy, Texas gets about 52% of its electricity from burning natural gas. But gas generation was reduced just when the state needed it most during the winter freeze last week because some pipelines froze and couldn’t deliver.
Wind turbines, which help supply about 23% of the electricity in Texas, also froze up when some blades iced up and couldn’t operate.
Jennifer Granholm, the former Michigan governor who was confirmed Thursday as U.S. Energy Secretary, said the U.S. electric grid needs to be strengthened, especially in states most vulnerable to changing weather patterns.
“Whether it’s wildfires in California or snowstorms in Texas, we need to upgrade our grid infrastructure ASAP,” she said in a tweet.
A federal report after widespread outages in 2011 urged hardening electric generators against extreme cold, but neither state regulators nor the Electric Reliability Council of Texas required plant owners to do more than file the weatherization plans. There are no standards for what must be in those plans.
Texas Gov. Greg Abbott said he now wants to force power plants to winterize after last week’s subfreezing temperatures knocked offline nearly half of the state’s generation capacity, at least temporarily.
“What we saw … was some very significant reliability issues related to the way the system was planned and the way the system was operated,” TVA President Jeff Lyash said. “The country is going to have to learn lessons from that. At TVA, we will evaluate what went on there very carefully and look for opportunities to strengthen TVA’s approaches to these kinds of challenges for our customers.”
TVA and its local power companies such as EPB insist the power grid in the Tennessee Valley is more reliable than what the Electric Reliability Council of Texas (ERCOT) provided to consumers during last week’s winter storm. The margin of total generating capacity above what utilities forecast each year for the peak demand during the coldest or hottest days of the year is nearly three times greater at TVA than the 9% margin used in Texas, Lyash said.
The biggest single source of TVA electricity is nuclear power, which is more resilient than most other types of power generation during weather extremes, and TVA also maintains a healthy mix of generation from natural gas, coal, hydro, solar and wind. More than 10% of TVA’s electricity comes from its 29 hydroelectric dams and its pumped storage plant atop Raccoon Mountain near Chattanooga, which can be activated as needed to meet demand peaks.
TVA also maintains more interconnections and is part of both the North American Electric Reliability Council and the new Southeast Energy Exchange Market to transmit power among utilities to help supply among different utilities.
Texas operates as its own electricity exchange area and its prices in most areas are deregulated to allow consumers to shop around for both the generating source of their power and the way it is transmitted.
Such competition, combined with abundant wind, oil and natural gas in Texas, kept energy prices in the Lone Star state 18.4% below the U.S. average and about 10% cheaper than in Tennessee during 2019, according to data compiled by the U.S. Energy Information Administration.
But the deregulated, more isolated market in Texas proved more vulnerable when a winter storm put the freeze on much of the state last week. Electricity prices peaked last week at more than 10 times their normal price, and many Texans are now facing both higher utility bills and extra expenses for lost production or broken water lines from being without power.
Melda likens Texas’ disaggregated approach to pricing in the energy market to pricing each part of your vehicle.
“If you are having trouble with your emergency brake, but you are only interested in the engine of the car, you might not want to spend any money on your brakes or your tires or other parts of the vehicle and that can incent some bad behavior,” he said. “At TVA we try to look at the vehicle as a whole and do what it takes to keep it running as safely and reliably as possible.”
Officials with ERCOT have claimed that the scale of the forced blackouts last week — the largest in Texas history — were necessary to avert a more catastrophic failure that would have wiped out power to most of the state’s 30 million residents for months.
Lyash said TVA’s integrated model where TVA both supplies and distributes power and works and regulates local power companies is different from the energy market in Texas.
“The value of the public power model goes beyond just dollars and cents,” Lyash said. “It is certainly focused on lowcost power, but we also want very high reliability and low carbon emissions. TVA has never rotated blackouts to maintain its reliability in its entire history and we’re going to work hard to make sure we never do. Yes, extreme weather events will always challenge the system, but no we cannot just accept that as a foregone conclusion. We have to plan for these risks.”