Eco-Thinker

It takes little sense to see just how non green the traditional combustion engine fossil fuel driven lawn mowers are. So those are obviously the lamest of all lawn care tools. And, the eco-friendlier reel mowers are too labor intensive for most large yards, try your hand at a solar charged electric lawn mower. This was an engineering project put together with step by assembly instructions including pictures.

Sources:
Appropedia
House Hacker