If there's one substance that it seems like a good idea to use as fuel for an automatic lawn mower, it's grass.
So goes the argument by EcoMow Technologies, who say they have a prototype of exactly that idea in the works.
EcoMow say their self-guiding robotic mowing machine uses the cuttings from your lawn to create a sort of "grass biomass", which it can harvest as fuel.
It also claims that the unused fuel pellets can be used for other tasks, including heating or even power generation.
And better yet, it's not years away - apparently a prototype will be ready by April. Unfortunately you won't be able to use it in your garden - the first version will be aimed at hay fields, not garden lawns, and will only be aimed at commercial farmers.
Eventually - by about 2016 - the aim is to have a model which can work in areas less than an acre in size.
EcoMow's CEO, graduate student Jason Force, said that he had the idea about five years ago, but it has taken this long to find the right funding and technology.
Force adds he has bigger ideas too - specifically for how it might work in the developing world:
"An application I’m pursuing is having little micro grids set up in East Africa where the units would go harvest during the night and then come back and plug themselves in to a power unit during the day and supply power to the local region during the day," he told GigaOm.