Boston Globe: Amid the maelstrom of controversy over the nation`s first offshore wind farm, one truth is as plain as the proposed 440-foot turbines in Nantucket Sound are tall: Its energy will be very expensive. That`s not just compared with power from coal and natural gas, but with renewable power from other sources. Once the 130 turbines begin rotating, the energy produced will cost up to 50 percent more than energy today from some land-based wind farms and twice as much as some …