Musk: The best way to harness solar energy—build lunar factories and lunar cities! Musk stated that the optimal way to harness solar energy is to extend beyond Earth. If we want to surpass the mere 1 terawatt of computing power per year, we must go to the Moon. Build mass drivers and a self-sustaining lunar city on the Moon—turning sci-fi into reality. Ultimately, we will venture among the stars and visit all galaxies. And the only way to achieve all this is to step out and explore.