On further thinking about kites pulling ships, why is it always just an “assist” rather than “the kite pulling the ship”? I mean, if a kite can exert a pulling force on the ship sufficient to save a certain percentage of fuel, why is the kite not simply made large enough to exert ALL of the force necessary to pull the ship? They never seem to explain that one. If one kite can save 20% of the fuel , then why not use a stack of five (5) kites and save ALL of the fuel? Could it be that the only “safe” position for these ship-pulling-kite companies is a slight decrease in fuel use, because if the effect is slight enough, they can just exaggerate the effect and get some sort of carbon credits or something when maybe the kite is doing next-to-nothing except this “virtue-signalling” we hear about so often? I think the whole thing is getting pretty fishy, if you’ll excuse the very weak pun. We still don’t see any yachts being pulled by kites except that same old symbolic catamaran covered with solar panels, which likely has a nice diesel backup for when nobody’s watching.
Not sure why kites can pull surfers along so well, and not boats, but at this point, it’s getting to be an old idea, with some pretty well-funded companies executing some impressive-sized demo projects, but to me, as with kite-reeling, there must be some reason why it never gets past the “prototype” or “demo” stage. It almost seems that with the number and power capacity of units produced and deployed so far, and the subsequent lack of follow-through, the technologies are in the process of disproving themselves(?)
Similar to hydrogen cars, which any third-grader could do the math on and see what a waste of energy hydrogen-as-fuel is. I just read that Shell has removed hydrogen fueling systems for cars in the UK, due to lack of use, and lack of interest. It is weird how otherwise sensible people and companies fall for the hydrogen story - 1/5 as efficient at 10x the cost - what’s the point?