Cargo generally isnt a target in the same way
Even putting aside exceptional situations like with the Houthis, we tend to get one or two highly public ship accidents per year. It would not be nice to have an incident like that involving a nuke ship every few years.
I feel like the solution for decarbonizing shipping would be carbon capture. Have the ships store the combustion products rather than exhaust them out, then reprocess them back into fuel on land using some other energy source (say, nuclear).
if it worked out, it would at least be relatively easy since pretty much all our infrastructure is designed around hydrocarbons.
Now ask yourself this: do I want vessels flagged in the countries with the least regulations and the most corruption to be run by a for profit maritime shipping company that skimps on maintenance budgets and crew costs to be running nuclear reactors with highly enriched uranium (weapons grade) anywhere they want around the world, even through pirate territory?
Fuck No I don’t. I barely trust the nukes running them in the USN!
Would you like some ketchup or ranch sauce?
I read somewhere that running on bunker fuel was the equivalent pollution of 50m cars.
https://sustainability.stackexchange.com/questions/10757/doe...
I think it was russia? that had nuclear powered ice breakers. Made sense as the constant power demands must be phenomenal.
For SO2 and NO2 pollution, not CO2. They are the most efficient way of transportation in terms of CO2 emissions. Ironically reducing their sulfur dioxide emissions is likely what caused the uptick in global temperatures the last two years. https://www.nature.com/articles/s43247-024-01442-3
Some shipping companies are experimenting with other ways to use wind. You can deploy kites to pull the ship, but that brings some operational challenges. The more promising idea are probably flettner rotors [1]. Those look like big spinning columns and work on the Magnus effect (how wind puts a 90 degree force on spinning objects). Their limited footprint makes them easy to integrate into existing designs, and since all they do is spin they are easy to use with the small crews of todays ships.
All of those modern ideas are mostly for reducing fuel consumption though, not replacing the engine entirely.
Huge kilometer square kites would be pretty cheap compared to the fuel budget of a ship, and clever routing and control systems can probably mean they reduce fuel consumption 80% for the same travel speed.
Not KM but 822m seems pretty close. I think you’re grossly overestimating the benefit from the kite. Seating’s current website says:
> A 1000m² sail surface to harness the power of the wind and tow ships. Based on modelling and preliminary land-based tests, Airseas estimates that the Seawing system can reduce fuel consumption and greenhouse gas emissions by an average of 20%.
I don’t think better routing will increase that to 80% even if you combine it with next gen tech that knows wave patterns and when a slot will be available to minimize speed and energy loss.
We need a path to remove fossil fuels from ships (& planes). There’s also industrial applications that need high heat that solar can’t really accomplish. Finally, solar & wind need insane battery capacity which when included pushes the economics strongly back in favor of fission and fusion.
We won't see discussions on that until we're serious about cutting fossil fuels.
Biofuels is also severely limited in supply and will in the future most likely be reserved for aviation, which is a lot more constrained than shipping etc. when it comes to which fuel options can be retrofitted on existing systems.
Realistic fuels that are being used now: 1. Methanol. 2. Liquid methane.
One could get (much) higher efficiency by using the heat from a nuclear power plant directly (never producing electricity) but I guess that would have to be a completely custom design.
If you have spare electricity (from any source), it's easy. Just capture some CO2 and react it with hydrogen with specific catalysts and at a high pressure. You can get methanol directly this way.
It's more expensive than fossil fuels at the current prices, so nobody cares.
Liquid methane is essentially the same as LNG, which is rapidly becoming the most popular fuel for newbuild ships today. But it's about as environmentally friendly as building natural gas powerplant to replace coal - a temporary solution at best.
Future solutions need a carbon-free fuel, period.
Methanol is slightly preferred because methane can leak, and it's a more potent greenhouse gas than CO2. However, even most of the CH4 leaks happen near the drilling wells, and in pipelines. It's unlikely that synthetic CH4 will have to be transported over long distances.
https://gcaptain.com/aet-orders-worlds-first-ammonia-dual-fu...
Ammonia fueling infrastructure does not exist, and its failure scenarios are just not going to be acceptable. Meanwhile, LNG fueling infrastructure is rapidly getting built out.
What's worse, ammonia is also produced from natural gas, it's used for process heat and as a hydrogen source. There's pretty much no "green ammonia". So instead of round-tripping through ammonia production, it's easier to just burn the LNG directly.
In future, we can switch to green ammonia, but then we also can use power-to-gas or power-to-methanol instead. Both are more efficient than ammonia synthesis.
Methanol production, in particular, can potentially scale down to very small facilities. In theory, large utility-scale solar or wind farms can have a methanol synthesizer unit, that will produce it when there's more electricity when needed. It can then be transported by regular tanker trucks.
Proliferation will always be a risk with nuclear reactors. We will never have nuclear powered civilian ships, as long as there exist pirates out there. Sure, Russia operates nuclear powered ice-breakers, but there are no pirates in the Arctic Ocean, plus, for Russia the distinction between civilian and military is not all that clear.
As for hydrogen, I think ships are the killer app. High pressure tanks or cryogenic tanks benefit from the square-cube law. If you want them to be economical, they need to be really large. They will never make sense for cars, or even trucks, but they can make sense for trains, and certainly for ships.
Wasn't one of the promises of thorium reactors a much lower risk of non-proliferation? (Here's a fun question, can one make a pebble bed reactor design with pebbles designed such that if a ship sank, could a special magnetic sphere of a 'correct' size pull in the pebbles but keep a safe distance? IDK but trying to think outside the box here...)
I think it's worth remembering that for the sake of many ships, we do not need the power-density of an SXX or even an AXX per-se.
> As for hydrogen, I think ships are the killer app. High pressure tanks or cryogenic tanks benefit from the square-cube law. If you want them to be economical, they need to be really large. They will never make sense for cars, or even trucks, but they can make sense for trains, and certainly for ships.
The bigger the tank, the more rigorous the inspection has to be to avoid risks due to hydrogen embrittlement.
I'll admit, I'm -less- worried about that property on a train than a ship, but on a ship I think we'd first need to see good evidence we can maintain things of such size on ground safely.
We might actually get more "nuclear powered" civilian ships, in a way. The reactors will be on land, where they can be properly guarded. And the heat and power will be used to manufacture carbon-neutral liquid fuel.
We gotta remember what a lot of the Marine world really looks like, under the covers.
That is, lots of them will use HFO aka Residual Fuel oil or 'bunker fuel'.
Switching to Biodiesel? Probably the 'cheapest' of the options, not sure what if any implications exist from the switch (lots of ships will stop burning HFO in ports and switch to more common diesel/etc, however not sure if there is a difference in some engines with doing so long term)
Hydrogen Fuel cells are likely as much of a 'refit' from a labor standpoint as switching over to a nuclear reactor; Also the general issues of hydrogen embrittelment and the like have not yet been solved AFAIK especially for the volumes needed for large ships, also not sure if there have been a lot of studies as to whether the hydrogen embrittlement problem could lead to larger structural integrity issues on such a vessel.
Nuclear, OTOH, has had at least a few 'non-military' ships (mostly nuclear icebreakers) with good success.
The current 'whitewashing' strategy of cruise lines is LNG, for whatever -that- is worth...
Edit: finger slipped and hit post too early, so a bit was added, apologies!
It certainly does. The higher the pressure, the worse it gets. And it absolutely applies to storage.
There are companies that sell various technologies for hydrogen-resistant coatings for pipes, for example.
If we would like to stop polluting the air, the future of maritime shipping is nuclear (fusion or fission). China understands that, and invests in R&D necessary to make it happen.
Plus, on ships, there's no competition with solar or wind. And nuclear will actually be quite cheaper than bunker oil, if executed correctly.