There was a local company doing this in my area a few years ago. They even stole one of my clients away from us. My client wanted to "go green" and so they dumped us for this guy who was using all electric battery-operated everything. After a while, the yard started looking pretty crappy. My old client emailed me for a clean-up to get his yard back in shape. I asked him, "What happened to that 'green' company who you hired a few years ago? They aren't doing your lawn anymore? He sort of sheepishly told me that the company went out of business. Too many problems with their equipment not lasting the entire day, batteries going bad, etc. The theory was good, but in practice, it didn't work out. So they went out of business.
Guess who's taking care of his landscape again now? Hehe.
I think it's an interesting concept and here in Portland there are definitely a lot of environmentally conscious people who would probably even pay a little more for this kind of service. The problem, apparently, is that the technology just isn't there yet. And you're never going to be as efficient with battery-operated equipment and solar panels as our crews are with gas powered equipment.
I think 20 years from now this could be very viable and may even be mainstream. But the technology just isn't really there yet.