"What ERCOT planners got colossally wrong was the availability of their fossil fleet: gas and coal plants failed.
Even a nuclear reactor tripped offline.
Our last report focused on the uniqueness of the Texas wholesale electricity market, ERCOT, and how it was specifically designed to evade federal utility regulation.
... One of the hardest parts of every planning agency’s job is correctly estimating future demand.
... we were surprised at how good their planning estimate was for this winter’s electrical load of about 67,000 megawatts.
... estimates published by ERCOT suggested about 72,000 megawatts of peak demand.
In total, ERCOT has the ability to supply electrical capacity of about 80,000 megawatts.
This amount of available electric power generation should have been adequate to meet demand this week.
Not by a wide margin but adequate.
... ERCOT runs “light” in terms of electric system reserve capacity with reserves typically about 8%.
This compares with other US grids where targeted reserve margins are about 15%.
Lower reserve margins are cheaper but mean less back up for emergencies.
Our first tentative conclusion is that Texas would have withstood this recent snowstorm and polar vortex event in pretty good shape from a grid perspective IF thermal plants were available to meet skyrocketing demand.
... There are about 20,000 megawatts of electric wind turbine capacity in state.
... it is not particularly windy in Texas in mid-February so the planners estimated that only about 6,000 megawatts of wind would be available.
This is approximately one third of the installed wind capacity and less than 10% of the projected ERCOT daily electrical system capacity.
This tells us that the ERCOT planners correctly viewed wind power as just not that big a deal in Texas in winter.
Of the 6,000 expected megawatts from wind, 4,000 megawatts were actually available this week to reap insanely high wholesale prices.
(One facilities operator noted that prices this week repaid a large portion of the entire capital costs of their entire wind farm project. )
... did wind under perform the expectations of planners?
Yes by about 2,000 megawatts.
... the total power system shortfall approximated over 30,000 megawatts.
Wind was only responsible for 2,000 megawatts of that deficit.
What ERCOT planners got colossally wrong was the availability of their fossil fleet.
They assumed almost all of it would be available this week.
... Texas is predominantly a natural gas and coal fired state with a few nuclear plants.
All those thermal units together comprise about 75% of the state’s electrical generation.
... ERCOT, at the height of their weather emergency, could only cobble together about 40,000 megawatts vs approximately 70,000+ megawatts of system demand.
... The gas and coal plants failed and even one unit at the South Texas Nuclear Project Unit tripped offline due to a cold weather-related instrumentation malfunction.
... there are two types of power plant outages: planned outages for thorough out of season maintenance and unplanned outages typically due to equipment malfunction.
In a summer peaking electricity system like Texas, it would be normal to have power plant operators engage in routine, extensive maintenance primarily in the winter when demands on the system are typically decreased.
(Unfortunately for ERCOT managers, the last week was anything but typical.)
A portion of their gas fleet was unavailable for this reason.
That’s the way it’s supposed to be in a summer peaking system.
... Texas’s second line of electricity defense, coal fired plants, also failed to perform as expected.
Coal piles, several months worth of stored coal on site at the power plants, froze into unmanageable carbon boulders and rendered much of the coal fleet inoperable.
... Are there places where natural gas, coal and nuclear plants operate quite well in colder climates.
The answer is of course, yes—all around the globe in fact.
We assume that whatever engineering and maintenance expertise that permits successful cold weather power plant operation can be brought to Texas.
...Texas is highly dependent on natural gas and the related infrastructure for two vital things—residential home heating and wholesale electricity production.
In extreme situations, residential heating gets precedence over power generation which sounds nice.
But as our readers know, a gas furnace doesn’t work without electricity.
... the gas distribution network—which also failed— uses electricity to distribute gas through its system of pumps and motors.
When the electric system goes dark there’s no power for gas distribution either.
Not to mention water pressure.
Pressures drop and systems fail.
This is not a resilient energy system.
... for many politicians it is much easier to prevaricate and blame the wind turbines.
... There is no reason for optimism if difficult, but science-based (energy) decisions are required in highly ideological environments."