PARIS (Bloomberg) — Areva SA, the world’s biggest maker of nuclear reactors, offered almost 600 million euros ($777 million) to buy wind-turbine supplier Repower Systems AG and tap rising demand for energy sources cleaner than fossil fuels.The cash bid of 105 euros a share for the 70.01 percent of stock that Paris-based Areva doesn’t yet own is 17 percent higher than last week’s close. Hamburg-based Repower said it favours Areva’s continued involvement and will consider the approach.