How a Gas Compressor Station Works
kimray.com
kimray.com
Sadly, the outages and possible the loss of life connected to it could have been prevented if the gas companies hadn't fought back against stricter weatherization rules[^0].
> they made recommendations to the Railroad Commission to implement weatherization rules on the natural gas supply chain because there had been water coming up from the formations — it's called produced water, it's naturally occurring — and it was freezing at the top of the wellheads and restricting gas flow both at the wellheads and in pipelines.
And yes, the Railroad Commission is not in charge of trains, but oil and gas in Texas.
[^0]: https://www.volts.wtf/p/whats-the-deal-with-the-texas-railro...
> When load is being shed involuntarily, customers designated as “critical load” can be exempted. Critical load is typically demand from entities, such as hospitals, for whom a power interruption could be extremely costly. To be deemed as critical, the customer must first file paperwork. The winter storm revealed that certain parts of the natural gas supply chain – such as natural gas compressor stations – were not designated as critical load. In consequence, their power was cut, thereby reducing flows of natural gas along the state’s pipeline network and contributing to partial and complete derates at multiple natural gas power generation units. The loss of their output in turn necessitated further load shedding, potentially creating an unstable feedback loop. This represented a single point of failure in the energy supply system.
https://www.bakerinstitute.org/sites/default/files/2022-02/i... (pages 13-17)
https://engineering.cmu.edu/news-events/news/2023/04/25-gas-... ("U.S. natural gas pipelines vulnerable to electric outages")
https://www.sciencedirect.com/science/article/pii/S104061902... | https://doi.org/10.1016/j.tej.2023.107251 ("How vulnerable are US natural gas pipelines to electric outages?")
Those should be the first requirements before being able to be deemed critical.
Heck, I’m familiar with some orgs that sell their backup generator capacity to be on-call to the grid in the event of supply shortage. To them it’s a profitable load test that reduces the risk of outage.
Strong agree; however, it would be highly unusual to find that any facility that knows to file critical load paperwork has neglected this, so I'm not sure that it would actually do much other than inconvenience the process.
It would be so great to regulate fixing that instead of getting rid of it entirely.
ie - we should responsibly use all the excess natural gas rather than flaring it?
I suppose gas distribution networks tend to be over-engineered for safety because if something goes wrong, it goes really wrong: https://en.wikipedia.org/wiki/Merrimack_Valley_gas_explosion...
https://en.wikipedia.org/wiki/Hinkley_groundwater_contaminat...
However, the article doesn't say what the "PIG" is (but talks at length about how the "PIG" is "launched" or "received"). Wikipedia says it's basically a passive device that gets inserted into the pipeline and pushed along by the pressure to clean or inspect the inside of the pipe.
https://en.wikipedia.org/wiki/Pigging
> Some early cleaning "pigs" were made from straw bales wrapped in barbed wire[4] while others used leather.[5] Both made a squealing noise while traveling through the pipe, sounding to some like a pig squealing,[6] which gave pigs their name.[7][8]
In the drinking water industry the pig is a large foam block that is shoved in the pipe, and the weight of the fluid behind it drives it along. It is used to physically loosen the accumulated debris on the inside of the pipe. This debris concentrates behind the pig, and when the pig arrives at it's destination you remove the pig and allow the fluid (and debris) to discharge to waste for a period of time until the fluid runs clear.
Some advancements include "ice pigs" which is just crushed ice. The advantage of an ice pig is you can hook up to a fire hydrant and pump the ice in, no need to access the mainline pipe itself. An ice pig will also disintegrate on its own, no need to remove it, just allow it to flow out of a downstream hydrant, any ice left behind isn't a problem.
Nowadays, they also have "smart pigs" that have sensors to detect gouges, dents, pipe wall that is too thin, etc. as the pig moves through the pipe, so that repairs can be made before the pipeline is filled with gas.
I’m guessing those are usually “dumber” ones.
Inside the tank terminals I had to witness and certify the pigging after each parcel loaded, when one chemical was done and the line needed to be cleared and volumes accounted for before filling with a different chemical. Among many other more or less toxic things. Measurement training was not easy in the full-scale industrial environment but you can't really lead as well in the micro-scale activities without it.
We have a natural gas line running through one of our agency properties, and it was recently repaired due to the pig's findings.
Basically the engineers running the pig mark sections of the pipe that need physical inspection. The crews come out, dig it up, and repair or replace a section depending on how bad it is. Or do nothing if the engineers see that it's nowhere near as bad as they thought.
Id imagine there's something similar in Houston, this stuff is legit fascinating.
Practically, that's fairly far from true for today's technology. Gas is so cheap that we're happy to waste a bunch of energy to make the plant cheaper.
Without those it would be just like a very very long garden watering hose that has a trickle of flow compared to a short one.
The differential pressure from one end of a gas pipeline to the other is not 1800 psi - it is more like 20 psi. You don't repeatedly recompress along the pipeline length - you compress once at the start, and decompress once at the end.
The reason to use high pressures is because for a given pipe diameter (and therefore cost), you get far more gas transported at high pressures than you do at low pressures.
> You don't repeatedly recompress along the pipeline length - you compress once at the start, and decompress once at the end.
There are often recompression stations in pipelines precisely because pressure drops across the length, and on land it's cheaper to have those along the length of the pipeline than one really big one like NS1 had.
Yes, you do. That is the primary purpose of transmission compressor stations. You may just lose a few psi per mile or something, but over the course of 100s of miles..
That's only true in a word with incomplete physics. Friction and drag exist, there's no sense pretending a process is imperfect because of them.
A natural gas powered permanent standby generator is amazing for peace of mind but they're a significant investment.
If something goes wrong with a generac, you likely need a service tech to come out. If my portable unit acts up I have a 2nd new one in a box just in case. They're so cheap you can basically afford to keep one fresh for each disaster.
I've had my 26kW generac for almost two years and it's done several multi-day outages without issue. I just have my mechanical contractor come out and do the annual maintenance on schedule, keep track of the weekly self-tests, and otherwise don't worry about it.
When we were shopping for houses out in the sticks, I had that generator budgeted right into the price of the house. If I got a multi-day outage very year, it's a no brainer.
It'll never pencil out in terms of dollars saved on lost food and hotels, but just knowing that the power will be out for a max of 15-20 seconds makes it worth it for us.
A portable inverter AC unit (ideally a dual-hose unit) will pull ~1700w on the high setting. You can cool a solid 1000 sqft even in the Texas heat with something like this while also running your lamps/wifi/starlink/fridge/etc.
Combine with something like an EcoFlow battery, and you can actually shut it off completely while you sleep (and lock it up inside safely). Setting the AC to the low setting will reduce its consumption to ~400w intermittently which will easily run on a 2.5kWh battery all night. The other advantage of the EcoFlow is that you can temporarily run much larger loads than the generator is directly capable of. Really good for induction cooktops and getting your washing machine spin cycle up to speed.
4 LiFEPO4 batteries run our fridge for about 8 hours. two 30lb propane tanks would run it for about a week, and the 30 gallon gas tank just recharging the batteries to just power the fridge could probably go 2.5 weeks.
Of course, once you run out of gasoline or propane, you are once again dependent on the infrastructure.
[1]: https://thehill.com/regulation/court-battles/4896585-texas-g...
The most significant laws Texas enacted after the freeze — HB 3 and 5, SB 1015 and 2627 - mainly establish new funding for gas-fired plant construction, cut funding for renewable construction, and allow energy companies to raise rates on customers more frequently.
Observers will note that gas fired plants had the most unplanned outages, while renewable sources had the fewest. In any case, what matters is that the $9/kWh costs are duly distributed to the customers and tax payers, to the benefit of energy traders.
1) Getting natural gas plumbed to your generator is expensive.
2) If you're running this generator for an extended period of time, things have pretty much by definition gone to shit and aren't working as designed. You have a lot fewer dependencies to go fill a couple of jerrycans with gas at the nearest gas station (that has both gas and power to pump it [0]) than you have to restore piped natural gas service to your property.
[0] And if a gas station loses power, getting it hooked back up restores its utility to everyone, whereas restoring power or natural gas service to a home only restores its utility to the person living there. Prioritizing gas stations over private homes makes a lot of sense.
If your threat model involves civilization deteriorating to the point where natural gas stops working then sure, a generator with fuel storage on site probably makes more sense. I'd argue that gasoline is the worst of available options though. Diesel and propane are much more shelf stable and typically more reliable than small gasoline engines.
Storing fuel is dangerous in general, but I believe that liquefied gas is more dangerous. It is more tricky. For example you need to store it in a ventilated environment, to prevent gas buildup. If you turned wrong nut you'll may be not able to turn if back due to pressure.[1] It can be treated safely, but it much more tricky that with liquid fuel.
Liquid Propane requires surface space to “gasify”, and more space the lower the temp. That’s (one reason) why propane “pigs” are horizontal cylinders.
Unfortunately, there aren’t many small horizontal tanks.
Down the line I figure I'll be building some sort of generator "shed", and perhaps look at using the generator exhaust to warm the tanks. A loop from the heating system would positively solve the problem, but that feels like way too big of a circular dependency.
https://www.sciencedirect.com/science/article/pii/S104061902...
Massive landslides and floods will wipe out your natural gas lines, your propane tanks, your wind and solar generators, your battery backups...
Gasoline is a terrible choice in any case, it goes bad quickly if you don't stabilize it. The only time I ever see gasoline being used it's with little portable generators. Even then, I see a lot of people starting to choose propane instead now.