If you've got the ability to build fusion generators, you've got the ability to create carbon-neutral analogues of existing fuels.
You've also got that ability without nuclear inputs, from conventional renewables (solar, wind, geothermal).
Those fuels can be far cleaner than bunker fuel, and a diesel or kerosene analogue burning in a well-tuned ICE or turbine would have limited negative effects. The marine-propulsion pollutants of most significant concern, aside from (fossil) CO2 are particulate, NOx, and SOx emissions.
All are far more prevalent with heavier fuels, and are concentrated largely along shipping lanes far out to sea, other than at ports. These tend to settle out / mitigate reasonably quickly, and I believe their long-term ecological impacts are fairly minimal.
The problems with nuclear marine propulsion are many, not the least of which are the 100--200 shipwrecks logged every decade or so, though you can add to that risks of piracy or terrorism involving nuclear propulsion. Keep in mind that present commercial fleets are on the order of eight thousand vessels. We've had experience with only about four hundred nuclear-powered vessels, virtually all military ships, of which about 170 are presently operational. The exceptions are three demonstration commercial vessels, the Otto Hahn, Savannah, and Mutsu, all of which failed to prove feasible, and a handful of Soviet-era icebreakers, now operated by Russia.
Fusion itself remains both technically and economically infeasable for any foreseeable future.
Gah! The present commercial shipping fleet is eighty thousand vessels, not eight. Lost a 'y' there.
About 1/3 of that is devoted to liquid fuel transport (oil tankers), a percentage which is down from the 1970s when it was roughly half the global shipping fleet. The absolute number of tankers has increased AFAIU, but other carriers, particularly container ships, have increased in fleet size faster.
There are also bulk solid (coal) and gas / LPG (natural gas) fuel carriers, though both are smaller than the oil fleet AFAIK.
And though I focus on shipping, synthetic hydrocarbon analogue fuels would also be useful to aviation. Probably the only way that large-scale long-range commercial flight will remain viable, if it does at all.
Tankers have also gotten smaller, at least at the top end.
The big 500k+ Ton (and that’s not a typo, we’re talking about 8 times heavier than the largest battleships ever built) ULCCs like Knock Nevis and Seawise Giant went to the scrapers a decade+ ago.
There is this misconception that fusion is far in the future. But these startups are aiming at commercial fusion before 2030. For instance, Helion plans for net electricity by 2024, in two years. Maybe the employees and the investors of these companies are fooling themselves and this will never happen. But they could succeed...
I am just providing pointers so people could have a look and juge by themselves. I was pretty convinced by Helion and ZAP, less by TAE.
Because we are on HN, I can mention that Sam Altman invested $375M of his own money in Helion, so he is indeed a true believer.
I think the expectation is that fusion is still a very risky bet. The upside is large (or at least perceived to be large) so a lot of funding has gone into it, but the actual chance of a breakthrough large enough is still small
For some of the pulsed fusion concepts like helion and zap, they're either very close to technical viability or to finding an unknown (at least by outsiders) deal breaker.
I'm much more sceptical on the economic viability. If it's past the edge of possibility with known materials now, there's no reason to think your reactor would suddenly last decades because you made a series kf incremental improvements from needing 10x the energy in as out to sorta do it once to 0.95x
You've also got that ability without nuclear inputs, from conventional renewables (solar, wind, geothermal).
Those fuels can be far cleaner than bunker fuel, and a diesel or kerosene analogue burning in a well-tuned ICE or turbine would have limited negative effects. The marine-propulsion pollutants of most significant concern, aside from (fossil) CO2 are particulate, NOx, and SOx emissions.
All are far more prevalent with heavier fuels, and are concentrated largely along shipping lanes far out to sea, other than at ports. These tend to settle out / mitigate reasonably quickly, and I believe their long-term ecological impacts are fairly minimal.
The problems with nuclear marine propulsion are many, not the least of which are the 100--200 shipwrecks logged every decade or so, though you can add to that risks of piracy or terrorism involving nuclear propulsion. Keep in mind that present commercial fleets are on the order of eight thousand vessels. We've had experience with only about four hundred nuclear-powered vessels, virtually all military ships, of which about 170 are presently operational. The exceptions are three demonstration commercial vessels, the Otto Hahn, Savannah, and Mutsu, all of which failed to prove feasible, and a handful of Soviet-era icebreakers, now operated by Russia.
Fusion itself remains both technically and economically infeasable for any foreseeable future.
<https://old.reddit.com/r/dredmorbius/comments/3c52ll/shippin...>