So power on mars is very difficult to accomplish as you may or may not know. Imagine you were on a bright sunny day in summer, in the middle of the equator of mars you would only get about 60% of the sunlight the earth gets. Now this is one problem but the other problem is dust storms as NASA plans to bring very thin and lite solar panels to harvest solar energy, dust storms are a huge issue as they could block out all the sunlight and there would be no more power
Now another way to get energy on mars is by bringing a nuclear reactor I know it sounds crazy but it is possible.
Rocket fuel can be actually made in such an astonishing way. There has been found to be a lot of frozen water on the surface of Mars, now this frozen water can be purified into liquid water, the good thing about water is that it is built-out of two elements hydrogen and oxygen these two elements can be separated and made into rocket fuel as it is the main components of rocket fuel and this process is called The Subati A reaction. Of course, you will also need a lot of energy and use mars atmosphere but this reaction is what we need most.