If you live in many parts of Texas, this week was not a good week to need electricity. Rolling power blackouts were ordered across Texas on Monday as a winter storm and frigid temperatures gripped the state and knocked out service to almost 4 million customers.
Natural gas, coal and wind turbines were frozen in the unusual cold snap and snow that hit all the major cities in the state. One of their four nuclear reactors also went offline because of a cold-caused false reading in a pump line from frozen water, not related to the nuclear side of the plant, just to be safe. It represented only 4% of the 30,000 MW capacity lost during this crisis and has comeback online.
The major loss is from natural gas. Wind performed poorly, but that was mostly expected in winter and bad weather.
Houston Mayor Sylvester Turner was upfront with the people of his city, “If you are without power right now, it is very conceivable that you could be without power throughout the rest of today and possibly even going into tomorrow.”
Some households have only had power for three hours over the last three days. With outside temperatures falling to single digits, many have taken to spending all day in their cars with a parallel increase in cases of carbon monoxide poisonings.
Warming Centers have opened across the state.
The blackouts were caused because Texas generates most of its electricity from natural gas and wind. Texas’ electricity mix is now 52% natural gas, 23% renewables (almost all wind), 17% coal and 8% nuclear. In this cold snap, gas used for heating increased dramatically, removing much of it from generating electricity, some pipelines froze up and couldn’t deliver, and there just isn’t enough pipeline capacity.
Wind turbine blades iced up and coal stacks froze. In addition, southern generating plants are not hardened against extreme cold.
As to the wind turbines, freezing cold and high humidity cause icing on the blades much the same as on aircraft. As Jeff Dagle, a Pacific Northwest National Laboratory researcher and expert in the areas of transmission reliability and control system security, puts it, “Like aircraft, the turbine blades work as an airfoil. But they don’t have de-icing abilities, so they won’t work if iced up.”
The rotating blackouts could continue until the state’s weather emergency ends, according to the Electric Reliability Council of Texas (ERCOT), the major grid operator that controls about 90% of the state’s electric load.
But it’s not just Texas. Southwest Power Pool, which manages electrical grid operations in North Texas and 16 other states, announced rolling blackouts as well.
“In our history as a grid operator, this is an unprecedented event and marks the first time SPP has ever had to call for controlled interruptions of service,” said Lanny Nickell, SPP’s executive vice president and CEO, in a news release.
Among the contiguous 48 states, Texas is the only state with a stand-alone electricity grid. Small pieces of three other grids serve the edges, but the state’s main electricity grid is operated by ERCOT which is largely isolated from the rest of the United States. This isolation means the ERCOT grid is not subject to federal oversight and is, for the most part, dependent on its own resources to meet the state’s electricity needs.
Texas’ electricity demand has increased substantially since 2010, but increased supply has only come from installing new natural gas and wind, bringing them up to 75% of the total generation.
Besides electricity, more than half of the gas goes to residential use like heating and cooling. The supply of gas is limited mostly by the pipelines, and as weather gets bad, either hot or cold, residential use gets priority. So electricity production gets short-shrifted, which is unfortunate for those three-in-five households in Texas that use electricity for home heating.
But these blackouts will re-occur whenever there is a severe cold snap, which seems to get more frequent as the weather extremes grow. Whether it’s Polar Vortices, Bomb Cyclones or just straight cold and snow, the energy sources most affected are gas, coal, wind and solar. Nuclear is generally not much affected, although one reactor was this week.
Coal stacks are frozen or diesel generators simply can’t function in such low temperatures. Gas chokes up – its pipelines can’t keep up with demand, wind turbines freeze up and there usually isn’t a lot of sun.
And prices skyrocket. Future wholesale power prices in Texas for early this week soared to $9,000 per megawatt hour from a seasonal average of $25.
Interestingly, nuclear prices usually do not go up – the reactors are generally unaffected and just keep running. In fact, they work better the colder it is. They don’t have to worry about fuel supply – they have enough on hand for years – and they don’t have to do anything special to deal with the extreme weather.
The only issues that can occur are in the non-nuclear parts of the plants. In fact, this week such an occurrence happened at Unit 1 at the South Texas Project nuclear power plant where an automatic reactor trip occurred as a result of a cold weather-related failure of a pressure sensing line to the feedwater pumps, causing a false signal, which in turn, caused the feedwater pump to trip.
This event occurred in the secondary side of the plant, the non-nuclear part of the unit. The primary side of the plant (nuclear side) was safe and secured. The other reactor was not affected and Unit 1 is back online.
Rotating or rolling blackouts occur when power companies cut off electricity to residential neighborhoods and small businesses, typically for 10 to 45 minutes before being rotated to another location, ERCOT said. Traffic lights and infrastructure may also lose power during these blackouts.
Oncor, an energy company serving parts of north Texas including Dallas, tweeted Monday that “our expected outage length of 15 to 45 minutes has been significantly extended. Outages due to this electric emergency could last for hours & we ask you to be prepared.”
This is why a diversity of energy sources is important. Just having mostly one or two sources, like gas and wind, leaves you vulnerable to unexpected changes, like this week.
Texas and the rest of the country needs to up their nuclear game, and achieve a diverse energy mix, or we won’t achieve any degree of decarbonization with any degree of reliability.