It would be useful to know how well it scales down. If you can put one on the back of a HEMTT, say, then you've effectively reduced the logistics train of a group of vehicles by a fair amount, if you're already grouping the vehicles.
Also worth asking if you could add one to VLCCs and container ships - if most of the fuel need of your bulk container carrier is effectively met by the vehicle itself then the carbon footprint of shipping is relatively low.
]]>That would require a solar collection system that's significantly more than 100% efficient. The energy used by the ship is vastly greater than available insolation.
Just quickly, if you look at fuel consumption it's going to be roughly 150 tons/day at an economical speed for a 10kTEU ship. At 40MJ/kg that's ~70MW. If we assume it's always cloudless daytime and the ship is always on the equator we get ~1kW/m2 so 70M is 70,000 square metres of 100% efficient solar panels. For a ship that's about 334x45.6m they only have 15,000m2 of area available, assuming it's also rectangular and nothing pokes above the solar panels. So those panels would need to be ~500% efficient. If we assume ~25% capacity factor from night time and other irritations the efficiency required goes up to 2000% efficient. Real solar panels run about 25% efficient unless you want to pay NASA prices.
https://www.seatrade-maritime.com/asia/hhi-builds-koreas-first-10000teu-containership
]]>But if you include the efficiency of the fossil motor (~50%) and real panels (~20% areal efficiency) as well as batteries so you don't still need a full size fossil motor you still end up trading a lot of cargo capacity for more solar area. If you make a "hybrid" setup that uses solar directly to boost/substitute fossil power I suspect it could work, but you'd want solar panels that you can use as the deck of an aircraft carrier. Coz that's the obvious thing to put them on.
This thing has effectively zero cargo capacity but is entirely solar... and they have built the whole boat around that, from the hull design up.
https://toronto.citynews.ca/2013/07/19/solar-powered-boat-catches-rays-as-part-of-scientific-voyage/
Note that the "useful" solar powered boats have sails for propulsion, and the brutal answer there is that weight for weight solar can't compete with wind, especially if you include batteries for night work: https://www.treehugger.com/awesome-solar-boats-you-must-see-4857671
Where solar powered boats work is the same as any other solar powered transport... you build a stationary solar farm and ship electricity to the moving bits. That can be using wires, mobile batteries, or making chemical fuel that reacts with air that can be more compact because you don't have to ship the oxidiser.
]]>Thanks. Yeah, I see it's a higher-value target than a simple fuel dump.
Don't get me wrong, I do think it's a good idea ... and if it works it could be a great idea. It's just not something that should be near where the actual combat is taking place. It needs to be built somewhere far beyond the range of the other guy's artillery.
In Ukraine's current situation it would serve better if it were built in Lviv rather than in Odessa ...
I think output would shrink in proportion as you scaled down.
But the main problem with shrinking it down so it would fit on a HEMTT is "Where are you going to set up the mirrors?"
And how long are you going to be able to leave it set up? And how much fuel could you produce before you had to move?
Same problem with where to place the mirrors applies to mounting it on ships.
]]>The basic problem with solar power in general is that you get on average around 300 w/m2 (average solar hitting the Earth's surface) times whatever your conversion factor is. Think of it in light bulbs per square meter and you see the problem. Solar ships certainly do exist, but they're like solar cars--optimized for efficiency, not cargo capacity.
There is, however, an enormous solar engine a ship can tap into: winds.
So basically, the best solar-powered ship is a windjammer. And that seems to be where a fair amount of experimentation and innovation is going on in the shipping industry.
The problem with going back to windjammers is that they worked in a world of around a billion people or less. Starting around 1900, our species foolishly hitched the nitrogen part of our required nutrient cycling to nitrogen fixed using fossil fuels, so there are a lot more people now. If we can't move bulk fuel, fertilizer, and grain, we'll be in even more trouble than we are already. Winds are more fickle than engines, and that's more than a bit of a problem for the global supply chains we're now stuck depending on.
]]>If I can chime in, there's a nineteenth century solution to this...
Yeah, I was only pointing out that the https://www.dailykos.com/stories/2022/7/24/2112238/-In-the-field-a-50-kW-solar-tower-reactor-is-fed-only-CO2-and-water-and-produces-jet-fuel under discussion probably wouldn't work scaled down to fit on a ship because there's no room for all the mirrors.
I'm sure there are plenty of ways to move the ships about. This just doesn't seem to be one of them.
]]>Sorry, missed the lead-in. I quite agree.
Others who point out that trapping drone power on stationary solar farms and shipping it from there aren't wrong either.
The odd thing is that, once we got away from muscle power, we explored the most energy-efficient forms of travel (boat, rail) first, then got crazier with energy expenditures as we went along. Actually this isn't entirely odd, because efficiency is how you get around having small, inefficient motors and limited fuel supplies. Still, the point is not to denigrate what looks like older tech when we're looking for efficient systems. Those technologies were explored first for good reasons.
]]>Odd? Those existed as muscle powered transport (canal barges, the first tramways) because they were viable with low power inputs. The efficiency was needed to get round that long before the first motors were substituted for the oxen and horses.
]]>Others who point out that trapping drone power on stationary solar farms and shipping it from there aren't wrong either.
Yeah, my only quibble was the suggestion of putting it right up near the front lines (assuming it's the kind of war that has "front lines") to save on logistics costs won't really work.
Putting it within range of the other guy's artillery just makes it a high priority target that's easy to take out. Put it back beyond the range of the other guy's weapons and truck the fuel up to the front.
]]>Current reports out of Ukraine suggest that 200km behind the lines does not count as 'beyond the range of the other guy."
Reports out of Afghanistan in the last two decades suggest that 2000km isn't a guarantee either, especially if the other side has a staging area.
This looks like a harder problem in the 21st century than in the 20th, and much harder than in the 19th.
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