Engineers develop a process to make formate fuel from CO2

Also, it could be wherever nuclear wouldn’t be permissible otherwise (e.g floating in the middle of the Pacific Ocean extracting CO2 from the atmosphere, away from populations that don’t want it nearby)

Yup, said another way, this would only really make sense if we are producing more energy than we can reasonably use and need to sink it somewhere.

However, there are so many sinks for energy that I just doubt CO2 will be a priority any time soon. Desalination, for example, will almost certainly end up being a huge energy sink as the world gets hotter.

Biomass is practically free (minus harvesting costs).

Free energy is not necessarily a fantasy. In Australia, the wholesale electricity price regularly goes into negative, usually many hours in an average day, reaching as low as -70c/kWh occasionally (more commonly -5c/kWh). There is just no enough energy sink to absorb all the power we generate from solar in the day time. If we can store some of this energy in a stable form, that would be a good win.

We have so much plastic, I almost wonder if it would be easy enough to burn it, capture the CO2, and convert that into new plastic.

Scalable CCU at source in cement production would be great at getting the 8% or so of global emissions related to cement production down somewhat. Other ways of tackling cement production related emissions are less CO2 producing alternatives to clinker, and even reusing old concrete panels in new construction. There are many rational, viable paths to address this, and other CO2 emission sources - but as long as CO2 emissions don’t have a cost associated, incentives to research, scale and push alternatives forward are lower than to keep doing what we’re doing

That would violate the conservation of energy. Put simply: The energy that is released from those CH3 complexes has to be put back into them to make them be CH3 complexes again. Otherwise you could, for example, heat your house by burning the same bit of fuel over and over again (using some of the energy released by the combustion to recapture the carbon and rebind it to the hydrogen molecules and leaving the rest as heat to enjoy all through the winter). Alternately, you could generate a tremendous amount of electricity by the same method.

Sadly, thermodynamics says, "No."

Waterborne shipping is even more efficient, we need to repeat the Jones Act in the US.

You won't be able to ship 300+ people across Atlantic any time soon on a EV glider. So, a realistic take is using biofuels instead of kerosene for aicraft engines.

>FF aviation should be abandoned because of the climate change implications.

(I'm talking specifically about overseas travel here, where electric trains are impossible)

FF aviation currently doesn't have an alternative - we could theoretically use hydrogen or synthfuel, but 1) synthfuel is not remotely viable right now and 2) hydrogen would require major plane redesigns (and new infrastructure), so even if it turns out to be viable it'll take decades. Also, I'm not sure if it'll be viable.

In terms of climate change implications, abandoning FF aviation only makes sense if we abandon all climate emissions ASAP, because FF aviation is one of the hardest forms of emissions to actually replace. Aerospace is hard, and FF aviation is already as efficient as is possible with current technology, given the sheer amount of savings an extra percent of efficiency gives the airline company.

>It's extremely inefficient. Large EV gliders are workable.

Aviation in general is extremely inefficient; it comes with the territory of being heavier than air but insisting on staying in it while traveling cross-continent.

Large EV gliders can only cross seas by being extremely lightweight - those things don't even have pressurized cabins, let alone hundreds of passengers (hundreds of passengers means the plane is hundreds of times more profitable than a 1-person). And I'm willing to bet they travel a tad slower, to boot. If you don't care about speed, then airships are the obvious best option - they were functional back in the 1910s, and were abandoned largely because 1) aeroplanes outperformed them and were then produced in large numbers for WW2 before being subsequently sold off once the war was over, and 2) they were seen as unsafe - not unreasonably given that the 1930s aviation industry put far less emphasis on safety compared to today, but also because the Hindenburg was designed to use helium but was forced to deploy using hydrogen for geopolitical reasons*.

Airships are still more expensive than aeroplanes - if only because they tend to fly much slower, and the subsequent flight duration requires paying out far more hours to flight staff - and the flight speed is a serious qualitative problem (one-week business trips aren't viable and ditto for week-long vacations), but they're technically doable. Although at that point, why bother? Why not take a cruise/cargo ship?". This is why there's no airship industry, by the way. They're too slow to compete with planes and too expensive to compete with ships/trains.

*namely the US not wanting to support the mid-1930s Zeppelin company due to it being funded largely by the Nazi party and airships being associated with military usage at the time, and it probably didn't help that Zeppelins were being used for Nazi propaganda purposes at the time.

>Shipping by full EV maritime shipping is on the horizon. Hybrid cargo ships are already a thing. (Aasfjell)

Hybrid cargo ships don't mean much - they're just supplementing their power. Also, that thing is 5 metres wide and uses batteries; batteries are a dead end for cross-ocean shipping. Full EV maritime shipping is indeed possible and, depending on the cost of hydrogen fuel, quite viable. Although hydrogen has its own problems and isn't particularly good as a fuel (it's specific energy is great but it's energy-density is literally the worst, and it's hard and expensive to store due to needing special tanks and liquefaction or compression, and it slowly leaks away at a rate of ~1% per day so it's harder to stockpile, and it's incompatible with existing fuel infrastructure and engines, and with current tech it's expensive AF to produce renewably so we're essentially gambling that those particular technologies will improve rapidly if we invest in them).

Although given how hard it is to get the shipping industry off bunker fuel, I'm not sure how we'd convince anyone to invest in a stinker like present-day hydrogen. Like, look at the above paragraph and how long that bracketed section is.

>Rail shipping is extremely energy efficient. This is how most cargo should be transported. A global rail transport network should be seriously considered.

Ideally we'd transport cargo by synthfuel cargo ships whenever the trip is near the coast; rail shipping in Indonesia is absurd, for example, and all imports/exports in Australia are obviously by ship. But more broadly, cargo ships are more efficient than trains, they're just not as clean because they're not electric.

That said, yes rail shipping is extremely efficient and a global rail transport network should be seriously considered, and rail is how most (overland) cargo should be transported.

> Shipping by full EV maritime shipping is on the horizon.

We' ve been building nuckear powered ships for like 60 years, they eork great, thry are nuch faster thsn normsl ones since they dont worry about energy efficiency and daving power.

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