[I'm half serious about this. I'm somewhat doubtful that it would work, but I like the idea. At the very least I think it would make a fantastic plot for a solar punk novel. If you want to rip it off for a story, go right ahead.]

I went to an ACX meetup yesterday and mentioned an idea that I’ve had off and on for a few years- terraforming the West Texas desert. They suggested I write something about it, so here is that something.

Land

West Texas has a huge amount of cheap land. I just went looking again and the first page of results were all between about $800 and $1700 per acre. Sorting by cheapest price per acre, I found several lots of 50 acres or so for 27-30k, which works out to about $550 an acre- and there are cheaper prices for larger chunks of land- there are multiple listings for 1000+ acre lots. The reason I mention this is to make it clear that the land out there is cheap and plentiful. The reason why it’s cheap and plentiful is because it’s damn near worthless- it’s desert. The water underneath the land is often brackish. The heat is unrelenting. The sun never stops shining.

Sunlight

West Texas is hot, dry and bright almost year around. Go to this website and select El Paso from the drop down- that region gets 5.87-7.42 peak sun hours every day, where “peak sun hours” is sunlight at maximum, unobstructed intensity- ~1000 watts of power per square meter. This is prime solar-panel land, but you can’t get that power to anywhere that people actually want to live. At a minimum, it would require hundreds of miles of power lines and infrastructure. If you wanted to use your electrical power locally, however, you have a near-endless supply. The only problem is storing it.

Storage

Conveniently, one of the other things that West Texas has in large quantities is brackish water, which coincides neatly with the cheapest land prices. You could store your electricity by pumping this water up into large reservoirs and retrieve it by allowing the water to flow back down to the aquifer through turbines. This is called pumped-storage hydroelectricity and it’s about 70-87% efficient- you lose 20-30% of your power, but once the water is pumped to the reservoir, there’s no loss of power over time- it can sit in a covered reservoir forever. Cool- but now what? You have endless electrical power and a method of storing it until you need it, but what’s the point?

Water

The point is this mid-sized industrial desalination plant. With endless electricity and gravity-fed brackish water, you could divert some of that brackish water from generating electricity to a desalination plant. I haven’t been able to find any detailed discussion of the power requirements for one of these machines. As for capability- the manual states that it can handle up to 2000 ppm total dissolved solids (TDS), which maps to the “slightly saline” regions in this report (page 5). There may be other, larger desalination plants for sale that could handle more-brackish water (3k-30k ppm TDS) which would give you more options, land-wise.

These desalination systems can produce 10-50k gallons of water per day. Which is a lot, but I'm not sure how much you would need- I imagine you could just have more than one desalination plant hooked up in parallel if one wasn't enough.

Waste

The waste from the desalination plant is all the crap that was in a large volume of brackish water, now concentrated into a much smaller amount of water. It seems like there are two possible ways to handle this waste. You could either dump it back into the aquifer that you pumped it out of or extract the minerals from the wastewater and sell them. Saline water contains salt, magnesium, calcium, potassium and a lot of other useful minerals. If it were dumped back into the aquifer, over a long enough period of time it would (I assume) make the aquifer more brackish than it was originally, which isn’t great. Extraction is probably ideal. This paper discusses different ways to extract minerals from brackish water- the most low-tech way to do it would probably be with evaporation pools.

The down side is that evaporation pools require a lot of cleared land and a very hot environment- but you would have both. The up side is that you could probably collect evaporated water from the pools to augment the desalination plant’s clean water output. If the evaporation method produced water quickly enough and in large enough quantities, it may even be possible to replace the more fragile and failure-prone desalination plant entirely. You would need to run the numbers on that, though.

Additionally, some of the minerals extracted from the water could be used in the manufacture of solar panels- I haven’t investigated this closely, but I know that lithium and magnesium (often found in high saline water) are used in battery manufacturing. Depending on the aquifer and the composition of the water, it’s possible that the solar panels could eventually produce an equivalent amount of minerals to replace those used in their manufacture.

It would be neat if so.

Why?

So now you have an unlimited supply of electricity, a storage solution that wastes 20% of your electricity but can store the remainder forever (not that big a deal given your plentiful electrical source), and an essentially bottomless supply of fresh water. All in the middle of a desert, probably hundreds of miles from the nearest large city where no sane person would want to live. So what, exactly, is the point of all this?

The point is to terraform West Texas.

West Texas is a desert wasteland studded with a few major cities, but otherwise populated entirely by crazy people who want to own land no matter how shitty that land is. Large parts of the state are absolutely worthless for either living or farming. What I've just described is (assuming it works) a method to sustainably produce clean water in large enough quantities to keep crops, trees, grass and animals alive and growing. Once a region is green and thriving with little to no water/electrical support from the outside world- you sell it to someone who will farm it and move on to the next project.

Cost

The cost of creating one of these farms would depend on how much water you would need to keep the land arable. Working backwards, you would find a desalination plant that could produce that amount of water, and then estimate the electrical requirements for both the plant and the distribution system (sprinklers, drip watering etc.) plus excess that would be necessary for the people who would live on the farm. The bulk of your expense would probably be solar panels.

Thing Cost
Desalination plant $13000 - $55000k
Land $5000 - $40000
Well drilling $4000 - $20000
Reservoir build ???
Solar panels ???

So a bare minimum of about $100k, probably double or triple that after everything is done.

Conclusion

The goal isn’t to make a real profit- the goal is to make enough of a profit to continue building more solar/desalination farms. A third of Texas is over brackish water. Something like half of New Mexico has brackish water. If large parts of that land were converted to sustainable farmland, the amount of food they could produce would be enormous, greatly reducing the cost of eating for anyone within easy shipping distance and reducing reliance on imported food from outside the US.

The same strategy could be used anywhere in the world where you have uninhabitable land that either borders on an ocean or has brackish aquifers underneath. This seems like a clear win for the future survival of humanity- If we can produce more food in regions that generally have to import, we could protect a lot of people from disrupted supply lines during global disasters and military conflicts.

EDIT: Someone on discord pointed out that dust makes it difficult to maintain solar panels in deserts. This is a problem that would need to be solved, but it looks like there may be systems in the near future that could automatically clean dust from the panels without damaging them.

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33 comments, sorted by Click to highlight new comments since: Today at 7:54 AM

This idea will not work, but it is delightful to imagine and I had fun thinking about it.

  • Farming is only really profitable in the USA when done on good farmland at large scale, on the order of several square miles. A square mile is 640 acres. The average price of an acre of good farmland is about $4,200, so buying a 5 square mile farm might cost about $13 million.
  • Irrigating an acre requires 5,000-8,000 gallons of water per day, so one desalination plant could handle at most 10 acres. To irrigate a farm of 5 square miles would require at least 320 of these desalination plants. Assuming each costs $13,000 to build, that's a cost of about $4 million for the desalination plants alone. The land would cost another $2 million or so. My guess is that the total costs of terraforming 5 square miles of land add up to around $10-$20 million and probably require extensive permitting, since you're extracting water from the common aquifer. I'm uncertain if your listed price for the desalination plant includes the cost of labor to build/install it. Either way, though, my guess is that your costs in terraforming this farmland will exceed your revenues, and that the buyer will perceive the land as inferior to better farmland with more established farming infrastructure that they could buy elsewhere.
  • Selling the minerals extracted from desalinated water might make some money, but in addition to evaporating off the water, you'd also need to separate the minerals and transport them to a buyer. The more minerals per gallon, the less viable the irrigation, and vice versa.

Yeah, and I think aquifer depletion would be a pretty big problem this would run into. Irrigating farmland requires ~twice the annual rainfall you get in texas. So terraforming projects might have to import water from the ocean.

I'm also concerned that there might be little-no topsoil.

I considered that. I wonder if you could plant some hardy, dry-climate crop the first few years and till it under to improve the soil composition.

Based on that Fermi estimate, the plan actually sounds surprisingly viable. It's already on the same order of magnitude as traditional farmland even without optimizing very hard, which means just a bit of added cleverness should put it in the realm of tractability.

That's a fair point. Let's look at some other sources and include fixed costs, and do some sanity checks on water requirements.

An inch of rainfall is about 27,000 gallons per acre, so to supply a 5 square mile farm with an inch of rainfall equivalent is about 87 million gallons of water. High yield corn needs 22-30 inches of rainfall per year. Peak season for corn is about May-September, so let's assume we therefore need about 22 inches of rainfall equivalent (1.9 billion gallons) spread out over 5 months or about 150 days. That averages to about 13 million gallons of water per day. That tracks very well with the original estimate of 5,000 gallons/acre/day, which would come out to 16 million gallons per day for this farm.

This company says a 27 MGD plant cost $87 million. If cost scales ~linearly with capacity, that suggests a $50 million price tag for the desalination capacity - now perhaps 4 times the normal cost of a farm of equivalent size. That puts the cost of desal much higher than the lower bound I used from the OP.

They also claim a unit cost (including capital cost, debt service, and operating cost) of at least $1.25 per 1,000 gallons of desalinated brackish water, which would therefore cost about $20,000 per day for this farm and create an added $3 million cost per year.

I don't have a great source here, but it looks like groundwater use for farm irrigation is typically free. Corn and soy yield optimistic profits of $100-$200/acre, or perhaps $320,000 for a 5 square mile farm. A $3 million cost per year is again an order of magnitude higher than those expected profits.

That's more like the sort of picture I was expecting.

I would distinguish terraforming from irrigation. It sounds like you are talking about setting up a self-contained system to irrigate the land every year, whereas I would restrict terraforming to a permanent climate change, so that it rains and desalination is no longer necessary. This is what people mean when they talk about terraforming the Sahara. The desert was green five thousand years ago when the pyramids were built, so it probably has multiple equilibrium climates and a sufficient intervention could get it to jump to the other. I don't know how plausible this is for other deserts. The idea is to irrigate a bounded number of times to grow appropriate trees to trap water.

A permanent change could be much cheaper per acre because the solar panels and desalination plant can be reused for new parcels. The downside is that this probably has large gains from scale: air flows freely between neighboring parcels and thus humidity is an externality. Whereas the whole point of a self-contained system is that you can start small.

We should go all the way and do NAWPA.  NAWPA was a 1950s proposal to send massive amounts of fresh water from rivers in Alaska and Canada south, some of it going all the way to Mexico.  The water normally goes mostly unused into the ocean.  Yes, there would be massive environmental disruptions in part because the project uses atomic weapons to do some of the engineering, but the project might reduce the expected number of future people who will starve by millions. 

the project uses atomic weapons to do some of the engineering

Automatic non-starter.

Even if by some thermodynamic-tier miracle the Government permitted nuclear weapons for civilian use, I'd much rather they be used for Project Orion.

The Soviets actually did try mining with nuclear explosives. They decided that it was too polluting. Since they had a pretty high pollution tolerance, I'm inclined to believe them.

I think we'll be sooner able to produce automated factories to produce automated self-repairing digging machines. There's a lot of interesting geo-engineering we can do with automated digging machines.

Aren't there limits to how much water you can pump out of an aquafer before destroying it?

[-]Ro2y83

An aquifer isn't an endless water sources. If you extract a lot of water and then evaporate it, it will lose water over time and go dry. So the whole project is doomed from the start of more than a few people try to live there.

How brackish is the brackish water there? because there are plenty of species of plants that tolerate brackish water, including some species of letuce, beets, barley etc.

You can also breed algae and fish in brackish water, like maybe crucian carp, silver carp or amur carp? Then use their crap to fertilise land?

The first hit on google says 1-4 parts per thousand, or about 1/10 as salty as seawater. If 0.5‰ is considered fresh, then that's probably plenty low to support some plants.

Afaik, the practicability of pump storage is extremely location dependent. Building it on plain land would require moving enormous amounts of soil to create the artificial mountain for it. Also, there is the issue of evaporation.

Another alternative storage method for your scenario to consider would be molten salt storage. Heat up salt with excess energy, and use the hot salt to power a steam turbine when you need the energy back. https://en.wikipedia.org/wiki/Thermal_energy_storage

Unless I'm misunderstanding, it seems like pumping the water up from an aquifer to the surface would be enough height to act as a battery- you wouldn't drain it to ground level, you would drain it back down into the aquifer.

Average water table depth in West Texas is 4.2 meters, and water weighs about 9810 N per cubic meter. If you dig a pit 1 meter deep to store the water at ground level, that reduces your height above aquifer to about 3 meters. You then can store about 30,000 J per square meter of pit area.

For perspective, that is about enough energy to keep a lightbulb on for 10 minutes. It is about .008 kWh. Average household energy consumption is about 30 kWh/day. You’d therefore need a pit that takes up about an acre to store enough energy to power your house for a day. This may interfere with your farming plans somewhat.

Many parts of west Texas are also suitable for wind power which could potentially be interspersed within a large solar array. Increasing the power density of the land might make it cost effective to develop high energy industries in the area or justify the cost of additional infrastructure.

This sounds to me a lot like a solution in need of a problem. Does the USA lack arable land? How much does arable land cost per acre in the USA?

I need a lot more convincing that this is worth doing...

If you convince people to live there, then there's more places for people to live and the population growth rate goes up. Many folks care about this goal, though idk whether it's interesting to you specifically.

The US isn't short on places to live, it's short on places to live that are short drives from the people and businesses you most want to interact with. If you want to found a new city, there are cheaper and more desireable places to do it; the difficulty comes from the fact that very few people want to go somewhere that doesn't already have a large critical mass of people, business and infrastructure already in place.

I would imagine that indoor farming would be far more desirable for the region - much better water efficiency, for one.

What would be more advantageous about the region, I imagine, is the regulatory environment, being in the middle of nowhere, Texas.  With an abundance of power and minerals, who knows what you could think up?

What is the goal? Is it to consume a particular resource? Is it to produce a particular product?

Yes, West Texas has abundant light and should have solar panels. Then you can ask what to do with the energy. You could just sell it to the grid. The advent of solar power will mean large daily swings in the price of energy. If you have a use of energy that can run in the mornings, that will benefit from this. Desalination is one such application. Colocating it with the solar plant has some advantage of reducing the negotiation with the grid, but that isn't theoretically necessary. This doesn't seem to me like a good enough reason to do things in West Texas. 

It hadn't occurred to me that brackish water is a resource. If brackish water has 1/10 as much salt as seawater, then it takes 1/10 as much energy (I think that is true both in theory and in practice, where practice is 10% efficient for both). So if you must desalinate water, it is a resource. I'm skeptical of desalination for agriculture. It's quite expensive, even at 1/10 the price. Whereas humans consume very little water and desalination for residential use is cheap, comparable to the cost of distributing the water. Let people in Los Angeles water their yards as much as they like. If people want to live in West Texas, they can water their yards, too. But this isn't a reason to live there.

If the goal is to produce food, is this the optimal use of energy? Maybe better to make fertilizer and export it to places that have their own water.

If the goal is to promote decentralization, then maybe you don't want to export fertilizer. But you probably want to think more about what you mean by decentralization (eg, self-sufficiency to survive trade decline vs escape from political oppression).

[-][anonymous]2y21

The actual showstopper is way simpler than you considered.

Solar panels and desalination equipment costs money and human labor to deploy and maintain.

If the cost is greater than the economic value of the gain, where gain = (cheapest already arable land) - (price of a West Texas acre), it isn't worth doing.

If I had some numbers on the cost we could check this numerically.  

 

How could you make this plan work?  Cheaper equipment that mostly deploys and maintains itself.


How could you get equipment that is cheap enough?  Make SoTa in AI just a little bit better, and deploy it to robotics that autonomously do industrial tasks with minimal human supervision.  Tasks like manufacturing and mining.  Including the manufacturing of themselves.

[-]jmh2y20

Perhaps I'm missing something here. Doesn't distilling the water (given the local solar power that should be near 0 cost) kill two birds with one stone? Producing good water for farming, and other human uses, and leaving all the minerals behind for use? 

I would think one might even be able to do some type of multi-stage type desalination with the available power that includes centrifuges that would at least produce some level of mineral separation that would be a value added step.

Last, seems that vertical farming tech has come a good ways and would also be a great fit into the effort. Moreover, that would also produce additional expertise/experience that may well prove helpful for exporting farming to both space and other planets/the moon.

Desalination plants tend to leave behind brine rather than pure minerals.

The existing vertical farming companies depend in their marketing on producing locally and being pesticide free. It's also easier for them to hire the necessary expertise near cities than in the middle of nowhere. 

According to https://www.energybot.com/electricity-rates/texas/ :

The average Texas commercial electricity rate is 9.38 ¢/kWh (22% lower than the national average).

I don't think that's enough of a cost incentive to counteract the increased difficulty in accessing skilled labor. 

I also don't see a good idea to expect an idea like "just build solar panels" to be a great cost improvement over the existing infrastructure. Building things in remote places without roads is more expensive and factors like the dust likely do matter.

[-]Ben2y20

Its a nice idea, and I suspect that in the far future more sophisticated versions of roughly this kind of thing will happen.

But it won't happen soon. This is the high fruit on the geography tree. It might be possible to develop a desert, but it would be much more cost effective to develop places that already have fresh water/soil etc. There are still lots of forests, jungles and grassy plains out there to be developed first. 

For energy storage, you might consider the Ambri liquid metal batteries. They're being designed for this exact purpose: coupling intermittent renewable generating capacity to steady loads.

Also, they're cheap, rugged, and don't seem to lose capacity over multiple charge/discharge cycles.

I don't want to live in West Texas, I want to live in Kauai but have it be located in the Bay area. If I had post-scarcity powers, I'd build an enormous floating greenhouse with a lush tropical island and coral reef inside. I'd park it off the peninsula, or in the Bay if I was allowed, and commute via drone-copter. Many delightful things are possible once we get this alignment thing sorted out.