Powering a data center often means tying into a national grid for the primary power source and backing this up with uninterruptible power supplies (UPS) and auxiliary generators. Environmentally conscious data center designs include more energy-efficient equipment and renewable energy sources of power. But alternative energy sources hydroelectricity, solar panels, wind turbines require geographical freedom and/or energy storage to balance out the intermittent nature of energy production. A better approach is to combine alternative energy sources and use fuel cells for power.