Creating clean -renewable- energy on Earth,in Space,or in Space Colonies for usage in either one of those,is important in having long-term growth for the space colonization efforts. With Solar Energy,which we can create in each Solar System, we have almost unlimited acces to solar energy. What we need is to come up with a way to efficiently store the energy,like in a battery. This battery can be picked up and replaced automatically by one of the Space Vehicles from a sattelite-based or planet-based solar energy farm. It could also be possible that the energy is transmitted via laser,between a Laser station and Solar sails. To gain as much energy as possible,we should not only have solar-sattelites,but also have solar-panels on Space Vehicles,Generation ships and on the roofs of Space Colon