Cooler Planet looked at the solar photovoltaic (PV) installation data from the California Energy Commission and made it visual to show just how it is growing. A static view of their data is at the right, but go to the site and move the slider to see the growth from only 1,675 grid connected photovoltaic installations in 2002 to 29,628 installations in 2008. According to SolarBuzz,
In 2006, 112 megawatts of solar photovoltaics were installed in the US Grid Connect market, up from 80 megawatts in 2005. Demand was led once again by California, which accounted for 63% of the national market. Notwithstanding funding program bottlenecks, New Jersey saw very strong growth in 2006, representing 17% of the national market.
Why would California and New Jersey, with only 12% and 2.9% of U.S. population respectively, account for such a large fraction of PV installations? Perhaps incentive programs (most recently the California Solar Initiative and the New Jersey Clean Energy Rebate Program) and other policies are working.
Internationally, Germany (8.8— U.S. in 2006 MW installed) and Japan (2.6— U.S.) are the leaders in PV installations, with California a “distant third” according to Lawrence Berkeley National Laboratory.
Most places where PV is economic have some combination of the following (but usually not all):