The head of a leading energy provider has claimed that the UK will find it very difficult to achieve European Union targets for increasing renewable energy usage.E.On chief executive Paul Godby told Reuters that the UK faced numerous obstacles if it planned on reaching the EU's target for 15 per cent of its total energy supply to be derived from renewable sources by 2020.In particular he highlighted issues relating to the availability of parts for developments such as wind turbines, issues relating to UK planning rules and possible problems derived from the National Grid."That is going to be exceptionally challenging," he told the website. "Getting 15 per cent of energy from renewables translates into getting 35 to 40 per cent from electricity. "We are nowhere near that and the obstacles getting there are formidable," he added.The UK currently produces just two per cent of its energy supply from renewable sources, though Greenpeace last week claimed that the EU targets were achievable, if an overhaul of the country's industry policy took place.