The up to seven hour run time with the optional front or rear mounted gas tank means the tractor is best suited to operations where it returns to base, it only takes five minutes to top back up.
The big attraction is the cost of fuel, around 30p/litre versus 60p/litre for diesel. But the system does require a specialist filling station which can cost in the region of £30,000-60,000 and if you are producing methane from AD plant it will need a scrubber to bring it up to a usable grade.
The 6.75 litre block is pretty much the same as the diesel powered tractor but the head and piston design is more akin to a petrol engine. Both methane models have the Electro Command transmission.