LONDON (Reuters) - Royal Dutch Shell is buying French renewable power company EOLFI as part of its plans to ramp up the oil major's electricity business.EOLFI has largely focused on solar and wind projects, including offshore wind farms. Offshore wind is one of the fastest growing renewables markets, with floating structures the technology's next frontier because they utilise waters that are too deep for traditional turbines fixed to the seabed.Shell, which generates most of its revenue from..