I say power the shipping industry with pelletized biomass; preferrably with red algae blooms as the feedstock.
Think of a pellet stove and all the dunnage and fodder it can burn, a true multi fuel engine!
Now build a multi-cycle biomass pellet fuled turbine engine using Brayton to rankine to sterling to thermocuple to atmosphere. With stacked cycles a net conversion efficiency of biomass directly to electricity could be upwards of 70% efficient!
Additionally the production of biomass pellet fule is magnitudes less intensive than the conversion of the biomass into a liquid fuel, adding to the improved overall cradle to grave cost, environmental impact, and fuel cycle efficiency!
It is Time for the transportation sector to get off the fluid bottle and start eating solid fuels!