While the government has adopted a range of targets for renewable energy and carbon reduction, there is still a lot of work to do to ensure the targets are met. Managing energy supply from variable renewables to ensure it meets demand is one of the key challenges in a transition to a renewable future. Because wind and solar power output is variable, new ways of balancing supply and demand are being developed. These involve a mixture of demand management, storage, backup from conventional power stations, and new grid connections to other countries.