Denmark, in 1997, decided to have a showcase island to show how an entire area can be independent of hydrocarbons. This is impressive. Go ahead and read this story of the Samsoe island.
Also, more importantly, check this link where a case is made for sustainable economic growth while going green.
Amazing...I think all other countries should ask Denmark to help them in establishing such hubs. One by one, perhaps in next 50-60 years if each country keeps a target of 50% of its needs from renewable / alternate sources, then there is a good chance that we will be able to handover this planet to the next generation in a healthier and greener state.