Can Renewable Energy Power the World‪?‬ Renewable Energy and the UK - for iPod/iPhone

Is a renewable-powered future for the world achievable? The International Energy Agency in 2013 predicted that within three years renewable electricity generation will grow to be the world’s second largest source of electricity ahead of natural gas and nuclear power. However while the European renewable energy council predicts up to 100% of power coming from renewables by 2050 BP predicts only between 10 - 20%. Who is right?