Extreme Cold and Power Availability: The Texas
Blackouts are Mainly Due to Lack of Winterization of Natural Gas Systems: The
Problem with Electrifying Everything
I live in a secluded rural place with fully electric heat
and power. A power outage means everything is out. Many people, especially in
cities and towns have a similar situation. I have a small propane/LP gas heater
for emergencies which I was about to turn on this morning when the power
luckily came back on after being out for about 8 hours or so from the ice and
snow storms. However, there is another possibly bigger round of ice and snow
and single digit temps on the way in a day or two. I have been having weather
anxiety. That’s me. Others in the central US have endured much colder
temperatures and those further south in Texas and Louisiana have endured unusual
snow to which they are not accustomed. Power operators in Texas and Oklahoma
have instituted rolling blackouts due to unusually high power demand and to a
large amount of power generators going offline. Generators of all kinds, fossil
and renewable have gone offline, 34 gigawatts according to Texas regulator
ERCOT. By Tuesday, a whopping 45 gigawatts of power tripped offline. This
includes wind turbines freezing up, natural gas pipelines freezing up, and
power plants tripping offline. Wind turbine freeze up is predictable and
counted into power availability. According to power operators wind offline wind
due to turbine freeze-up was actually less than predicted and on Monday added
up to 4 GW compared to 26 GW of natural gas generation off-line. Another issue
is that those generators in the south are not designed and maintained for cold
weather since it is rarely necessary. The reason gas pipelines are freezing has
to do with water vapor and hydrates in the lines freezing. Another issue has
been frozen instrumentation at gas wells and processing plants and freezing
cooling water at thermal power plants: natural gas, nuclear, and coal.
This simply shows that the infrastructure in Texas was not
built for cold, to northern standards. Newer wind turbines can be outfitted with
a thin layer of carbon fiber that can be heated. But it is expensive and can
reduce turbine efficiency. Thus, ice on wind turbines can be minimized as it is
in colder environments, but it costs and to be realistic that is not likely to
be a recurring problem in Texas. Since wind is only a small part of winter
supply in Texas the real problem is their natural gas delivery system.
Jim Robb, President and CEO of the North American Electric
Reliability Corporation put it like this:
“It may not be an event that you plan for, but it has got
to be an event that you are prepared for.”
Natural Gas Freeze-Off was the Main Issue in Texas
Texas has an isolated and deregulated power grid operated by
the Electric Reliability Council of Texas (ERCOT). They have abundant resources
including solar, wind, natural gas, nuclear, and coal. Due to that isolation they
can’t simply import power via transmission lines from neighboring grid systems
like California and other places do. During peak demand in Texas it is natural
gas that is relied on and demand for it shot up to very high levels. One issue
is that ERCOT under-predicted peak demand of natural gas in a worst-case winter
scenario. They predicted top natural gas demand at 67 gigawatts but in reality
it was up to 69 gigawatts. According to their forecasts only 7% of winter
demand was projected to come from wind. Another issue is not enough natural gas
storage and pipeline capacity near power plants despite more than adequate gas
supply. Texas does not have much gas storage. It is more of an on-demand system
from wells. It works fine except under extreme cold. Wells, gathering lines,
and distribution lines in Texas were nor designed for cold weather. Some gathering lines from wells are not even buried but above ground. Many Texas wells
require electricity to lift gas through oil and that electricity was off-line.
Another issue is that several natural gas power plants were offline due to
maintenance which is routinely done in winter months since the high-demand
season in Texas is fueled by summer heat not winter cold. Another vulnerability
in extreme cold is that the homes and businesses that do have natural gas piped
in for heat can rocket up demand quickly and overwhelm supply. The blackouts this
summer in California were caused by resource inadequacy. The blackouts in Texas
were caused by winterization inadequacy which led to resource inadequacy. In
both cases peak demand was not adequately forecasted. Gas supply went down due
to lack of winterization while gas demand skyrocketed. Gas from many Texas
fields comes from wells that mostly or partly produce oil and heavier, wetter natural
gas liquids. Water is mixed in as well and that water is what freezes. Water
mixes with hydrocarbons to form hydrates. Higher BTU gas is more likely to form
hydrates and freeze. The hydrates can freeze above the freezing point of water.
This ice in the lines can damage instrumentation. The fluids are separated out
at gas processing plants so much of the freeze-off occurs between wells and
those processing plants. Glycol absorption systems can take water vapor out of the
lines before they freeze. This is part of the gas dehydration system. In well
tubing, gathering systems, and pipelines in colder areas methanol is injected
into the system through pump or drip. It acts as an anti-freeze which lowers
the freezing point of the water in the system. Heat can also be applied where
pressure drops and where orifice sizes drop. Instrument filters can be used to keep
instrumentation dry and less freezable. Equipment freeze-up at gas processing plants
has also been a problem. Texas also makes more power from natural gas than it
did previously which compounds the issue. Yet another issue is freezing water at
facilities at natural gas, coal, and nuclear power plants. Freezing in
pipelines is exacerbated when pressure drops in gas lines or where flow is
restricted. Freezing due to pressure drop is called pressure differential. Once
in a high-pressure gas well during drilling on a hot summer day I saw an 8-inch
flow line become covered in ice as a high-pressure gas shot to the low-pressure
surface.
A paper by Texas author Tom Fay titled Freeze Protection
for Natural Gas Pipeline Systems and Measurement Instrumentation makes the following
conclusions:
“Freezing is a major issue in any natural gas system.
Being aware of the problem it can present and taking steps to prevent it are
critical for the integrity of the system and operations. Proper planning,
regular maintenance, and anticipating potential problems should be a priority.
Attention to those preventative details will ensure a smooth operation. Failure
to do so can lead to costly problems and affect a company’s bottom line.”
And I might add – it can affect the integrity of the pipeline
system to such an extent that reliability of supply is endangered.
Detractors argue that designing a system at considerable
added expense to withstand weather that only occurs in a handful of days in 20
years is impractical but millions of freezing people think otherwise. Texas
governor Greg Abbott is holding ERCOT responsible.
Electrifying Everything is Fine but We Need Back-up
Power and Better Reliability Too
Heat pumps are quite efficient, work great, and offer a good
means to decarbonize. They are fantastic for A/C here in Ohio in both effect and
cost. However, they are limited in extremely cold weather. Below about 14 deg F
many systems lose efficiency and provide less heat. Electric space heaters or a
properly vented propane/LP gas heater and fuel might be needed in those
situations. People with wood heat or unvented propane or natural gas heaters (that
combust very efficiently and don’t require venting) always have heat in a power
outage. Home battery systems are also a possibility but at a high expense for
something that may rarely be used. All-electric households are out of luck. Power
outages are most often caused by weather: snowstorms, ice storms, and storms
with strong winds that cause trees to break power lines and poles. Adequate preparation,
winterization, and maintenance helps but is not foolproof. In winter the power
is more likely to go out when you need it most for heat so that can create
anxiety if you don’t have adequate back-up. I predict as more things become
electrified that in the future the back-up systems too will become electrified
as battery systems continue to get cheaper and better in performance. There are
lithium battery systems now that can do much of it but something like a Tesla
Powerwall is not cheap. Yeti has a very flexible portable system the size of a
car battery for couple grand but it maxes out at 660 Watts which could
potentially accommodate an electric space heater (of some types) on its lowest
setting for a short time, maybe an hour or two, but that might be pushing it. Home
battery systems will have to get better and cheaper before they can provide
back-up heat but it seems likely that at some point they will.
Once again, Robert Bryce beat me to the punch in a pertinent Forbes article pointing out the perils of “electrifying everything.” He makes the interesting observation that concentrating all of our energy production onto our electric grid instead of keeping other power grids like the natural gas distribution piped into homes for heating would make things less reliable not more reliable. However, he doesn’t note that the excess demand on the natural gas heating side coupled with the excess demand on the electric side to favor the heating side. He notes rightly that we can store vast amounts of fuels like natural gas but only comparatively miniscule amounts of electricity for weather-related demand surges. He also suggests that some people, those that want to ban new natural gas hook-ups in states like New York, California, and Massachusetts are misguided. An all-of-the-above strategy is usually useful in demand surges. Diversification of energy supply is one way we help to ensure energy security. With talk about ecological anxiety or climate anxiety we tend to forget that weather anxiety related to immediate power availability is far greater, more warranted, and more immediately real than anxiety about some vaguely possible future problems.
References:
How Extreme Cold Turned Into a U.S. Energy Crisis – by
Lynn Doan, in Bloomberg, Feb. 15, 2021.
Millions in Texas, Oklahoma without power as grid
operators call for conservation – by Robert Walton, in Utility Dive, Feb. 16,
2021.
Severe weather, blackouts show the grid’s biggest
problem is infrastructure, not renewables – by Jonathan Shieber, in Tech
Crunch, Feb. 15, 2021.
Sweden Shows Texas How to Keep Turbines Spinning in
Icy Weather – by Jesper Starn and Krystal Chia, in Bloomberg, Feb. 16, 2021.
Texas largely relies on natural gas for power. It wasn’t
ready for the extreme cold – by Erin Douglas, in The Texas Tribune, Feb. 16,
2021.
Texas’ natural gas production just froze under
pressure – by Justina Calma, in The Verge, Feb. 17, 2021.
Texas produces more power than any other state. Here’s
why it went dark anyway – by Matt Egan, in CNN, Feb. 16, 2021.
Freeze protection for Natural Gas Pipeline Systems and
Measurement Instrumentation – by Tim Fay, in asgmt.com
Goal Zero Yeti 1500X Portable Power Station –
goalzero.com
Texas made few power reforms despite warnings. ‘An
incredibly dangerous situation.’ – by Mark Dent, in Star-Telegram, Feb. 17,
2021.
This Blizzard Exposes the Perils of Attempting to Electrify Everything – by Robert Bryce, in Forbes, Feb. 15, 2021.
