Rockville-based Clean Currents LLC sold its solar division to a San Mateo, Calif., solar power provider, which is also making an investment in the local green energy company. The privately held companies declined to disclose financial terms of the agreement, which closed last week. SolarCity, a nearly 5-year-old, 1,000-employee solar panel design, installation and maintenance company, said it will keep all of Clean Currents Solar's 12 employees, growing that Silver Spring office and warehouse location by another 30 people by the end of the year. "We were looking to expand to the East Coast for some time now," said Lyndon Rive, CEO of SolarCity, which provides solar power products to more than 10,000 residents and businesses in Texas, Colorado, California, Oregon and Arizona. "We probably interviewed 20 to 30 companies." Clean Currents had separately approached SolarCity last year about joining solar forces. "It was just great timing," said Gary Skulnik, Clean Currents co-founder and president. Discussions between the companies began last summer, and Rive said the local company's leadership set it apart from the dozens of other potential acquisition targets in the area. Lee Keshishian, another Clean Currents co-founder and its vice president of operations, has headed up the Clean Currents Solar division and will move to SolarCity with the acquisition, becoming the larger company's regional director of the Washington-area operations. He will remain on Clean Currents' board. SolarCity said it plans to offer its first solar panel products to D.C. and Maryland residents and businesses in mid- to late February. Tapping a $700 million-plus fund it maintains from financing partners U.S. Bank, PG&E Corp. and National Bank of Arizona, the company designs and finances the full installation of pricey solar panels for customers, signing them on to 20-year solar power leases that it says results in lower monthly bills than traditional electricity alone.