Called "Green Power Island," the goal here is to leverage not just one green energy solution, but mash a bunch of them together to create one whopper of a renewable powerhouse. It's more than what you see on the surface, too, thanks to some clever engineering.
So you can see the wind turbines and the bed of solar panels and green space for "biofuel crops," but what you can't tell up front is that the island is actually a big water reservoir for hydro-electric power, too. Architectural firm Gottlieb Paludan out of Copenhagen designed the system to help balance out one of the big problems with renewable sources: you typically can't have it all the time. The sun isn't always shining, nor is the wind always blowing.
EarthTechling's Susan DeFreitas does a good job describing how it works:
Paludan has taken this strategy and given it a new twist with his proposed Green Power Island. His design makes use of seawater pumped into a lagoon-like reservoir built into an artificial island. When demand is low, pumps driven by wind turbines empty the reservoir. At peak periods, water is allowed to flow back into the reservoir, through turbines generating electricity to meet the rising demand. By positioning the reservoir within an existing body of water, the system removes the necessity of having to create two reservoirs at different heights.
Green Power Island is still an idea in the drawing room, but, considering Denmark's aggressive pursuit of green energy, they certainly seem the country to do it.