Bear in mind that solar capacity and actually fulfilling electricity demand from that capacity are two very different things. The capacity factor of solar is between 20-30% as compared to >50% for fossil fuels and >90% for nuclear [1].
Hydrogen powered aircraft are hypothesized, but require lightweight hydrogen vessels. Maritime vessels can only be feasibly powered by nuclear power. The energy density of batteries is orders of magnitude less than fossil fuels, and sail boats cannot feasibly fulfill demand for shipping. There's a very strong aversion to nuclear energy, so we'll probably be burning fossil fuels in ships for a long time.
Thank you for mentioning nuclear ships, they are a very important and totally ignored piece of the puzzle.
We already have a large nuclear fleet of ships, but they are mostly warships and ice breakers. But as soon as you mention that giant containerships should be nuclear people go ballistic!
They also miss the fact that a nuclear container ship would be 2-3 times faster as fuel economy is a non-issue. That means it would go a long way in replacing air freight and land freight, where you don't need shipment in a day but can't wait a month.
By the looks of it's due to public fear, we will end up using synthetic fuel.
You might have a point on offsetting normal fuel by sequestation, but in terms of policing and managing abuse, synthetic fuel might be easier.
Ships can probably be run off hydrogen, and if that is impossible for some reason you can always make synthetic fuels. Airplanes could also run off synthetic fuels, but since airplane emissions are actually a lot worse than just their CO2 output, that is not a good solution.
Hydrogen has good energy per kilogram, but bad energy per square meter even in its liquid form [1]. Liquid hydrogen is less than 10 times as dense as water.
Synthetic fuels either require considerably greater arable land and water consumption to grow biofuel, or the use of things like algae cultivation and accelerated decomposition. It's probably more effective on a $ / CO2 mass basis to just sequester carbon and keep using refined fossil fuels. Airplanes account for a single digit fraction of the CO2 emissions from transportation, though, as their mass and drag are both tiny as compared to cargo ships.
Reply to your post below, HN is not letting me respond:
Those synthetic fuels are effectively the same as biofuels. You're using energy to sequester carbon out of the atmosphere (or a body of water, in the case of algae based biofuels) and using that carbon to power a machine.
You can either do this by using electricity generated from another artificial power source, as in your example. Or you can do this by harnessing natural energy, like setting up transparent pipes to collect solar energy into algae or by farming biomass on land. Since most energy decarbonization plans assume modest energy consumption growth, and sometimes even an overall energy consumption reduction the former plan is less feasible than harnessing naturally occurring energy.
Hydrogen powered aircraft are hypothesized, but require lightweight hydrogen vessels. Maritime vessels can only be feasibly powered by nuclear power. The energy density of batteries is orders of magnitude less than fossil fuels, and sail boats cannot feasibly fulfill demand for shipping. There's a very strong aversion to nuclear energy, so we'll probably be burning fossil fuels in ships for a long time.
1. https://en.wikipedia.org/wiki/Capacity_factor#Capacity_facto...