State attorney general Kamala Harris Jan. 12 issued a ballot summary for an initiative to close a tax loophole and use much of the resulting revenue for energy efficiency and clean energy programs. The measure would raise an estimated $500 million in fiscal 2012-13 and $1 billion\/year after that. Half the money would go to energy efficiency and clean energy subsidies and half to education. The initiative is titled \u201cTax Treatment for Multistate Businesses, Clean Energy and Energy Efficiency Funding. Initiative Statute.\u201d It would require businesses that operate in various states to calculate their income taxes for California sales revenue based on California rates instead of potentially more favorable rates in other states where they operate. The measure would apply for five years. After Harris approved the ballot summary, secretary of state Debra Bowen announced Jan. 13 that the proponent, Joseph Caves, can circulate a petition to qualify the measure for the November ballot. Caves must gather 504,760 signatures by June 11. He provided no contact information in his application to circulate the measure for signatures.