North Texas saw a severe winter storm yesterday that has left much of the state in darkness. The storm has left more than 3 million customers without power, while the freak weather conditions forced the closure of oil wells, refineries, meat plants, and numerous stores. The fierce storm also has left 25 people dead in Texas and other states.
The outages are likely to continue because of problems that the operator, CenterPoint Energy Inc. has had in restoring service. Outages have extended into North Dakota, Arkansas, Louisiana, Mississippi and northern Mexico.
In Texas, because of its location in the southern U.S., snowfall is rare. The last time Houston saw a snowfall of more than 4 inches was in 1960. Due to the infrequency and weakness of snowfall in Texas, the Texas electric system infrastructure is not designed to operate in extreme weather such as that which occurred on Tuesday.
With this extreme weather, the use of electric power to turn on heaters peaked in demand, while supply was unable to deliver the power as its infrastructure froze causing a blackout in the state.
All electrical energy sources failed in Texas
In recent years, Texas increased its reliance on wind turbine power generation, currently having 31-gigawatt hours (Gwh) of installed capacity, about 25% of the state’s electricity supply. With the snowfall, the wind turbines froze, leaving the state with less than 6 Gwh available from wind sources. However, wind sources should not be blamed as the state of Texas only relies on them for 10% of total winter generation.
Although the system has batteries to store the electrical energy produced by wind generation, due to the low temperatures, they lost up to 60% of the stored energy.
Nuclear energy was also unable to respond to the shortage. In Texas, there are only 4 nuclear reactors near Houston and Dallas. In Houston, one of the reactors had to be shut down because the safety sensor froze, depriving Texas of 1.2 Gwh of electric power in the middle of the blackout.
Still, the central problem came because the pipelines carrying natural gas froze. Up to 66% of Texas’ electricity generation relies on natural gas during the winter seasons. With the freezing temperatures, up to half of the state’s natural gas production stopped, leaving the state without its main winter power source.
With the unexpected snowfall, Texas’ reliance on both wind and natural gas power was called into question, as neither source was able to respond to the cold temperatures. In the face of such atypical weather, the Electric Reliability Council of Texas (ERCOT) stated that the decision to shut down the system and leave it without power had to be made because there was a risk that the system load would go out of balance.
“If the system load did not stay in balance, the state was at catastrophic risk of cascading blackouts. Those are far more serious than even what we’ve seen, because they put critical operations, such as hospitals, police, and emergency response, at risk. Those would not be outages that could be restored, but they could have lasted for weeks,” said Bill Magness, president of Ercot.
According to Magness, the return of power will depend in the first instance on “how quickly gas plant operators can get back up and running.” Secondly, it will depend on how fast the temperature rises, because as the temperature rises, it will allow other generation resources such as wind turbines to become available. This will facilitate the transport of resources for power generation such as fuel for thermal and gas plants.