Our steam cars when they are working return around 8-9 miles to the gallon on fuel, we dont use petrol we use petrol diesel mix (aka contam) from the local garage which cost nothing as they have to pay to get rid of it normally. water wise the condensing cars can do a claimed 100miles on a tank of water but you have to have a way of removing the oil from the water as oily water is not good inside a boiler.
Steam cars failing to catch on is a far more complicated than just fuel. Steam cars compared to petrol cars of the same period where a lot faster both in acceleration and top speed and almost silent (a friend of ours has just sold one that did 85mph and was still accelerating when he bottled it) and im sure that Antarmike will comment on them being silent lol. The maintenance cost were higher and they where expensive to produce, Stanley's were almost 10x more expensive than the Model T.
If they were not so expensive to purchase I would driving one now but with prices starting around £15000 and going to around £500000 insurance for a start if you are using it for commuting would rule it out.
A viable alternative for a cheep car/ military vehicle to run would one with a multi fuel engine.
I had heard that some will run on vodka that's bloody cheaper by the litre than fuel in some places. anyone know of a multi fuel engine that would fit into a Series Landrover?
Pete Stevens-with-a-v