Creating a magnetic field as strong as Earth's would require a significant amount of energy, but the exact power needed depends on the method of generation. Maintaining a magnetic field with electromagnets requires power, while a static magnetic field does not. The energy stored in Earth's magnetic field can be estimated using its magnetic strength and volume, yielding a rough figure of around 10^21 joules, though this estimate is highly approximate. To generate this amount of energy, the total power generation capacity of the world, approximately one terawatt, would need to be sustained for centuries. Additionally, the infrastructure required for such a project, particularly for cooling superconductors, would greatly increase the energy demands.