Another problem with biofuel - petrol or diesel - is the increase in solvency over conventional fuels. Critical assets need to be cautious before converting. Any sludge sittlng at the bottom of the tank will resuspend and foul fuel filters. If tanks are clean - no problem.
I'm sure our navy is aware of this and taking appropriate action.
That is probably pretty cheap compared to what the taxpayer is paying now for fuel that is guarded by USN ships in the Persian Gulf, military assets in Saudi and Kuwait and all the other little scams that are going on to ensure that the oil companies maintain their profit margins.
It might seem ridiculous to pay $26 a gallon but the Navy knows what the other stuff really costs and it won't get any cheaper.