Google Inc. has thrown its financial clout behind a proposed 350-mile underwater electric cable off the U.S. East Coast that could form the backbone of a grid carrying power from future offshore wind turbines.  Japan's Marubeni Corp and New York investment firm Good Energies are joining in financing the project, which will be led by transmission-line developer Trans-Elect. The cable will help developers of offshore wind projects to surmount a major cost challenge -- connecting their turbines back to the grid in a way that allows them to sell to multiple customers. Google announced the move, which it called an investment in "a superhighway for clean energy" on its corporate blog.  Google, an often-quirky company, said in late 2007 that it would begin to invest in companies and fund research into producing affordable renewable energy. It has also invested in onshore wind and solar energy. The Internet search giant did not disclose the anticipated cost of the cable, which would run from Virginia to New Jersey, but The New York Times reported it as about $5 billion. Source: MSNBC