[xyzzyz]

> We should be blanketing every inch of desert with solar. And pair it to use excess energy for carbon fuels synthesis.

Is there any EROEI analysis for this approach? Direct air capture of carbon is rather energy intensive, because CO2 concentration in the air is really rather low, whereas making solar panel is very energy expensive. If we can’t get enough useful energy from the panels during their expected lifetime, we shouldn’t be blanketing deserts with those.

Also, blanketing the deserts with panels is difficult due to environmental regulations, read eg. about desert tortoises at Ivanpah, and the cost of their relocation. If we want to use deserts to generate energy, first we need to solve the problem of environmental regulations blocking it.

[Veserv]

The price of a good is almost always higher than the price of the energy invested (usually significantly). Solar panels are used for generating energy. Therefore, if a solar panel is profitable to buy and operate, then it almost certainly generates more energy than it cost to produce.

Solar panels are profitable and are one of the cheapest marginal sources of power in many places. Therefore, solar panels are almost certainly net positive.

Synthetic fuel generation is probably not in the current environment. Storage is not a major problem yet at the current power generation mix. It may become competitive if storage becomes a problem, or if solar drops in price by 66% or more.

[Plasmoid]

Quick napkin math.

Direct air capture is about $300-$600/ton of CO2. The numbers for this are terrible as everyone is posting estimates of what it'll cost by 2030. So let's pick $300/ton of CO2.

If we could convert captured CO2 directly into gasoline, it would have a market price of $170. This is already pretty problematic because I'm ignoring the cost of getting the hydrogen for gasoline, or the fast that 75% of CO2 is useless oxygen.

More realistically, there is $60 worth of gasoline in that ton of CO2. And you still need to pay to get those hydrogen molecules.

[numbsafari]

> solve the problem of environmental regulations blocking it

Or, like, come up with solutions to the environmental externalities posed by blanketing anything with solar panels.

[xyzzyz]

There is no guarantee that this is possible.

For example, if farming didn’t already exist, it would probably be illegal to start it, because of how turning big patches of earth into monoculture completely destroys preexisting ecosystems. There is no known effective way to mitigate this damage, efficient farming at scale requires this, and inefficient methods will require more land and likely cause more damage.

Similarly, blanketing deserts with solar panels will very much significantly damage existing fragile desert ecosystems. You can maybe avoid some of the negative aspects by carefully chosen procedures, but in general, there is no way around it.

The question is whether the specter of environmental destruction will hold us hostage, and allow other, grandfathered environmental destruction to proceed.

[anon84873628]

Permaculture people would probably argue about the higher productivity of permaculture systems (which theoretically have a better shot at maintaining/mimicking natural ecosystems) versus standard monoculture farming. The problem is that permaculture outputs don't fit neatly into the existing industrialized food supply chain.

In theory we could produce more food and fuel while preserving diverse ecosystems, but it would require refactoring our entire conception of what we eat, how it is produced & preserved, distributed, etc...

[xyzzyz]

“Permaculture” is just a meme among hobby farmers with an environmental knack, it’s simply not possible to feed the people this way (whatever permaculture actually is in practice, as it seems to mean something different every time I hear about it), and even then it still destroys the preexisting ecosystems.

> The problem is that permaculture outputs don't fit neatly into the existing industrialized food supply chain.

No, that’s not a problem, “food supply chain” will buy produce from you with not a lot of concern of how you have grown it, as long as it meats the specs. The problem with “permaculture” kind of stuff is that it simply doesn’t produce adequate amounts of food, relative to required investment of labor. That’s the problem with it, not “industrial supply chain”.

> In theory we could produce more food and fuel while preserving diverse ecosystems, but it would require refactoring our entire conception of what we eat, how it is produced & preserved, distributed, etc...

I hear this kind of vague stuff often, but rarely any concrete proposals. Whenever I do, these almost always involve reducing the human population to a fraction of existing population, and have the remaining ones consume only a fraction of what people consume today, with higher labor investment required from each. This is, obviously, a non-starter, which is why actual, concrete proposals are not forthcoming.

[sn9]

https://caseyhandmer.wordpress.com/2023/01/09/terraform-indu...

[JumpCrisscross]

> Direct air capture of carbon is rather energy intensive

How does it compare to letting plants do the capture?

[anonuser123456]

So like… grow switch grass, harvest it and burn it to harvest the flu gas co2?

[JumpCrisscross]

> grow switch grass, harvest it and burn it to harvest the flu gas co2

Idk if you burn it. Digest it, maybe, into a fuel or whatnot. My point is biomass is a more-familiar industrial input than whatever comes out of direct-air capture .

[anonuser123456]

co2 is pretty valuable as feedstock. If you burn it , you can recover the potassium and phosphorus to reseed the next batch.

[anon84873628]

Well once you have the grass you could just ferment it into ethanol... An option that has been available to us this entire time...

[ebiester]

That works for things like E85, but does not for airplane fuel or diesel or natural gas or...

The density of ethanol is the issue, no?

[pfdietz]

Photosynthesis is ruinously inefficient. Beyond that, turning CO2 into reduced carbon uses even more energy than just concentrating CO2 does.