Wasn't the main issue with this that fuel is paid for by cargo ship customers (the container owners), not the shipping company? So the shipping company doesn't want to spend a ton of capital to get a 10% discount to all their customers, and there was no way for thousands of random customers to exert pressure on the shipping company to do so. Basically the economics didn't make sense.
The economies of this make sense if there's more than one shipping company (they'll be cheaper and get more business) or if they just change how they charge, neither seems that hard.
