bmcage writes "Belgium wants to build an artificial energy storage island within 5 years. The island will store excess energy produced at night from the offshore wind farms already present in the North-Sea. From the article: 'Belgium is planning to build a doughnut-shaped island in the North Sea that will store wind energy by pumping water out of a hollow in the middle, as it looks for ways to lessen its reliance on nuclear power. One of the biggest problems with electricity is that it is difficult to store and the issue is exaggerated in the case of renewable energy from wind or sun because it is intermittent depending on the weather. "We have a lot of energy from the wind mills and sometimes it just gets lost because there isn't enough demand for the electricity," said a spokeswoman for Belgium's North Sea minister Johan Vande Lanotte.'"