Aluminum Smelting is actually one of the main industries in Iceland due to cheep electricity costs which are below below US, Europe, and China. At the same time Iceland's renewable energy industry provides over 70% of all the nation's primary energy and 99.9% of Iceland's electricity being generated from renewables. Iceland has explored the feasibility of exporting hydroelectric energy via submarine cable to mainland Europe and also actively seeks to expand its power-intensive industries, including aluminium and ferro-silicon smelting plants. http://en.wikipedia.org/wiki/Economy_of_Iceland
The largest geothermal power plant is in the US and Iceland actually receives most of it's electric power from Hydro Power. They are almost done another 690 MW peak 525 MW av hydro power dam which is being created for the Fjarðaál smelter. http://en.wikipedia.org/wiki/K%C3%A1rahnj%C3%BAkar
They do use geothermal for home heating which has an above normal payout in large part due to the cold preventing normal heat pump's from working at reasonable efficiency and the long winders preventing solar home heating system from working when they are most needed them. Most of the continental US can use solar hot water heating systems with a fairly fast payback for lower cost than Iceland's geothermal systems.
I am just pointing out that "green" tech is already competing with fossil fuels and winning in many areas. It's not a question of turning off coal and other fossil fuels today, but rather limiting their use to the most useful systems such as cars and airplanes.
PS: Many homes in the US would reduce their CO2 emissions more by adding insulation than they would by doubling the fuel economy of their cars.
