"The problem, he adds, is one of incentives. Ship owners, who would normally borrow for such upgrades, do not benefit from lower fuel bills. It is the firms chartering the vessels that enjoy the savings. But their contracts are not long enough to make it worthwhile to invest in green upgrades. The average retrofit has a payback time of three years, whereas 80% of ship charters are for two years or less."

"Hence the interest in new green-lending structures. ... The idea is to share the fuel savings between the shipowner and the charterer over a longer contract, giving both an incentive to make the upgrades. Such schemes used to be thwarted by the difficulty of measuring exact fuel consumption on ships. New technologies allow more accurate readings."

This is the exact same problem that arises in landlord/tenant relationships when it comes to things like insulating a property. Insulation might be relatively cheap and pay itself back in a few years. But the landlord doesn't have an incentive to insulate because the benefit goes to the tenant. The current tenant also won't insulate because they'll probably leave before they can realise all the benefit of their investment.

In theory, landlords or shipowners should have an incentive to invest, since it should improve their property and therefore allow them to increase their rents or charter fees, but for some reason this doesn't happen. Possibly consumers can't accurately assess the value of improvements so they are reluctant to pay more.

The measurement devices mentioned should allow both parties to have a more accurate way to share in the benefits.

It's a complicated dance of incentives and information...

https://en.wikipedia.org/wiki/Externality https://en.wikipedia.org/wiki/Information_asymmetry