APS (Arizona Public Service) is an electric company serving a good part of
Arizona. They have a special plan where you can but electricity that
is generated from renewable resources like wind, geothermal and solar.
It is really inexpensive and is automatically added to your bill. For
most people the cost to go 100% green will be less than $20 a month.
Check it out at
http://www.aps.com/main/green/choice/choice_7.html
