Great promises to recycle unused CO2. Will the world run short of CO2 to be recycled into liquid fuels? Could every liquid fuel burner capture the CO2 produced and return it to be recycled?

At 10000 gallons/acre/year, USA could produce most of the liquid fuel required on 36,000,000 acres of sunny desert lands and xxxx million tonnes of CO2. Are those essential elements available? If not, how much could be made available?

Costs I have seen put just the costs of the bioreactors as making the process uneconomic, let alone cleaning them and so on.
I will believe this one when I see it working at scale.

Industrial waste CO2 - coal and gas smokestacks.

The real result of going this route would be to extend the number of years during which we continue to burn fossil fuels.

"Whoa! We can't shut down that coal plant! That would put the Sunflow plant out of business."

"Damn the climate change. Full fossil fuel speed ahead."

(EVs run on "$1/gallon gas".)

Ethanol fermentation plants produce CO2.

As a true skeptic I'm going with TT on this, I will hold back the cheers until I've seen independent confirmation. However, assuming it is true I have other questions.

What are the costs collecting the waste CO2 and transporting it to a solar fuels plant? This process still needs acres of cheap land and land near a CO2 producing industrial site is likely already been put to use (in other words - not cheap).

What is the well-to-wheel efficiency of this process? If you have arces of cheap land why not go with solar/wind to electricity?

Coal, propane. Global climate change.

The reason this site exists is to present information about "Green" cars. Not "black" cars.

More efficient fossil fuel cars while we develop truly clean cars, fine. But fossil fuels should not be the end game.

We may need liquid fuel for flight. Fine. Let's see where we can affordably create non-fossil fuel liquids without screwing food production.

Algae and some perennial grasses such as switchgrass show promise.

A new variety of switchgrass has been engineered that produces far more sugar than its parent. Switchgrass will grow on poor quality land which isn't usable for food/fiber production. Switchgrass is a native American plant that used to cover much of our plains, so it will do well without a lot of supplemental water and fertilizer. It has a massive root system which sequesters carbon and improves the quality of the soil.

Now that, to me, is a liquid fuel worth pursuing.

Setting up a plant to suck up coal smoke and use a lot of valuable solar electricity - not so.

Miscanthus, switchgrass and other plants that can grow where we don't grow food are promising. Which we grow where would largely depend on temperature/moisture/soil type needs.

About half our oil use goes to personal transportation and about 10% of that oil goes to plane fuel. Growing 5% of our oil input seems possible.

Move half of our moderate distance public travel to electrified high speed rail and we only need to grow 2.5%.

That might be true of all the hardy perennial grasses. They must put down a boatload of roots in order to harvest the sparse nutrients and water characteristic to the areas in which they have evolved.

Some of the early studies with switchgrass were done on farmed out cotton fields in the deep South. A few years of growing perennial grasses on that otherwise unusable land really increased the quality of the soil.

I can see planting ribbons of some of these grasses in our grain areas as a way to trap water and fertilizer runoff. Keep some of the fertilizer out of our streams and slow the movement of water on the surface. Reduce erosion and allow more absorption into the aquifers.

Every few years the grass ribbon could be moved to improve a different parts of the field. Grain producers would be compensated by having a crop to sell for fuel and by improved soil.