If you have a good, compact inexhaustible source of clean energy that gives you megawatts of it, you should be able to turn it into delta-V. You can use atmosp

If you have a good, compact inexhaustible source of clean energy that gives you megawatts of it, you should be able to turn it into delta-V. You can use atmosphere as the propellant. And accelerate as much as you need at the upper levels of atmosphere. Potentially you can use aerodynamics (basically fly inverted) to get to even higher velocity than the orbital velocity. Then, you can stay there at the upper levels, as long as you need to, and charge your tanks (you can initially take off with an empty tank of propellant). Once this is done, you can adjust the angle of attack and ease of into the higher orbit, switching to space flight. It involves hypersonic flight, but there is nothing impossible here.