I want to find out about companies leading the fight against global warming. I've found a few overseas companies (like Norway's REC); but I want stocks of domestic companies. I've tried a couple screeners but it doesn't seem like the "category" is even recognized yet. Any help will be appreciated.

I am really interested in investing in Green technology, specifically solar, wind, or hydrogen energy. If you could just give a few names of stocks/companies that would succeed i would greatly appreciate it thanks.

The oil companies take the money they make and buy back there own stocks so the value of the stocks go higher.. Shouldn't they reinvest the money in renewable energy