The problems that the rock face are somewhat more significant than whether you tanker to achieve an arbitrage. Lighting uses around 7 times more energy than all of the global air traffic at present.
A quick look at the international energy outlook, IEO is interesting reading, and would suggest that the effect of tankering is hardly the problem that exists, it is a minor bump in the underlying data, approaching trivia.
https://www.eia.gov/outlooks/ieo/
