Thomson ReutersTesla Motors Inc has won U.S. antitrust approval to buy solar panel installer SolarCity Corp , moving closer to its goal of creating a carbon-free energy and transportation company. The Federal Trade Commission said on Thursday that the deal was approved. It was on a list of proposed transactions that were granted quickly because the merging partners have few or no overlaps. Tesla said in July after it made its first offer that by acquiring SolarCity the two companies would form a one-stop shop for clean energy, offering consumers solar panels, home battery storage and electric cars under a single brand.