Power Plant Converts Fruit and Veggie Waste Into Natural Gas For Cars

Zothecula writes "Some readers might remember the Mr. Fusion unit in Back to the Future that Doc Brown fills with household garbage, including a banana peel and some beer, to power the iconic time-traveling DeLorean. While we're still some way from such direct means of running our cars on table scraps, researchers at Fraunhofer have developed a pilot plant that ferments the waste from wholesale fruit and veg markets, cafeterias and canteens to make methane, which can be used to power vehicles."

Comments

Re:Expand it to cover more fuel sources.

[bigmo]

Actually high cellulose content products don't work much at all. You need a high nitrogen content material (poop is the preferred material, ideally bird stuff because it contains the urine as well). There is a particular ratio of carbon to nitrogen that works best and by using various combinations of poop and different vegetable matter you get a mixture that gives the most methane and the least CO2. Vegetable leaf matter by itself will work, slowly, but produces a much higher CO2 to methane ratio so is not very useful for combustion. I assume that actual fruit and vegatables have higher nitrogen content than the leaves.

I built a few methane digesters in the 70's and I can tell you that it's not as easy as it sounds to actually produce useful amounts of methane. There is a lot of continuous mixing that has to happen or thick viscous mats form and keep things from working right. This consumes energy. You also can't really compress methane much without using more energy to compress it than you get out of it.

Of course if it's armageddon and you have lots of pig poop & crazy midgets to run things, this could actually work.