Farm use and deliveries in the neighborhood.
Just a question I think people might find interesting, not necessarily something I’m going to do.
I’ve been day dreaming about starting a neighborhood composting service; picking up 5 gallon buckets of scraps and dropping empties. Since compost produces methane, I could collect and fuel my ‘fleet’ with it.
How hard of a job would it be, could an average joe do it? Would it even be worth it to try?
What qualities would you look for in a conversion donor? I was thinking truck, but a van or something totally different might be a better fit.
It's not worth it.
CNG/LNG is not a good car fuel. It has poor energy density, and it's expensive to produce. Vehicle efficiency is poor.
The vehicles, which are expensive, already exist. Look up the Chevrolet Impala Bi-Fuel .
Honda had a Civic but stopped making it because it never took off.
You'd need A LOT of compost to produce enough methane to fuel a car full-time. Municipal landfills produce usable quantities of gas, but they haven't really figured out how to efficiently collect it, not that I've seen, at least. You will have the same problem with compost. You also would need to filter out unwanted gases certain composts produce, like hydrogen sulfide, carbon dioxide, water vapor...
As @mmj said, gasoline and methane are very different fuels. In order to be volume efficient in a vehicle, methane needs to be compressed and liquefied. That takes a completely different storage tank design from gasoline. You'd need something like a propane tank for a grill. You would also need a compressor and chiller to store and maintain the collected gas as liquid.
I think it is a better idea if you get an old reliable diesel and run it on kitchen oil. Of course some modifications will be needed.
https://www.youtube.com/watch?v=kXyuWe4Jhng
