... A 'green power' program regularly invites customers to pay $4 to $10 extra per month to switch to clean energy.
VOA: standard.2010.03.23
In addition, the U.S. Environmental Protection Agency (EPA) in April announced the top collegiate purchasers of renewable energy through its "Green Power Partnership, " voluntary program that encourages governments, businesses and schools to buy renewable energy.
The recently released guidance for Qualified Energy Conservation Bonds (QECBs) explains what constitutes a "green community program, " and provides guidance on how to measure and certify the 20 percent energy savings provision for publicly-owned buildings.
The figures come from The Global Trends in Renewable Energy Investment 2012 report, a UN Environment Program backed study that has tracked the finance flowing into greenenergy across the world since 2004.