A sharply growing number of electricity meters are spinning backwards. That's what happens when a homeowner or business installs typically a solar system at his or her property and "net meters' the output.
Net metered energy facilities are booming nationally and especially in Pennsylvania. Nationally the number of net metered projects grew 61% in 2010, jumping to 155,841. Net metered projects operated in 49 states and 694 utility service territories. http://www.eia.gov/renewable/annual/greenpricing/pdf/green_pricing.pdf. Only Tennessee apparently forbids net metering. Most net metering takes place on residential and commercial accounts.
Net metering growth was explosive in Pennsylvania during 2010, skyrocketing 350%, with the number of net metered facilities up from 650 in 2009 to 2,971 in 2010. Pennsylvania ranked second in the growth rate of net metered projects, trailing only Maine.
Nationally, California accounted for more than half of all projects with 86,495. Colorado ranked second at 9,776.
In 2011 through to today, the net metering boom nationally continues and even may have accelerated. America now may have between 250,000 and 300,000 net metered energy facilities. The overwhelming majority of which are solar.