Grace over at AT Los Angeles reviewed an electric lawn mower not that long ago to mixed results (she liked the quiet, emission free performance, but the mower's cutting coverage was small and the battery drained quickly). There are options in the robotic lawn care category, with hands free and even solar operated lawn mowers which combines the utility of a traditional mower with the convenience of a Roomba robot vacuum...
posted originally from: Unplggd
Husqvana now offers a solar amplified Automower which is rated for 0.6 acres, taking advantage of any sunny skies to supplement its power use while mowing. The mower handles an area of 1,100 square metres in about 10 hours during daytime, so the machine isn't exactly the most expedient of lawn mowers. But considering it's robotic and very quiet because of the electric motor, who's complaining? And yes, the units come with theft-protection programming, which kills both the use of the mower while also sounding off an alarm if tampered with.
Check out Husqvana's whole range of robotic mowers here.