Fuel literally burns and it is carried by ship - I believe there is a way to safely ferry them in ships.
For the tar that a container ship burns, it's not going to be very volatile. Coal also burns quite well, but unless it's powdered, good luck trying to ignite some with just a match.
Special ships? That probably depends on the economics. If the Electric Car Industry makes it worth a shippers while - Someone will invest in a special purpose vehicle.
So now we are at the first stages of this - in time - if the industry succeeds - the money will come.