Theoretical framework that measures the level of technological advancement of a civilization based on the amount of energy that it is able to harness and utilize. The scale was proposed in 1964 by the Russian astrophysicist, Nikolai Kardashev. To learn more, see the Wikipedia article.
A civilization that is able to harness and utilize all the energy available on its own planet. This would require the ability to harness energy from sources such as wind, water, and solar power.
A civilization that is able to harness and utilize all the energy emitted by its own star. This would require the ability to build a Dyson sphere, a hypothetical megastructure that surrounds a star and captures its energy output.
A civilization that is able to harness and utilize all the energy available in its own galaxy. This would require the ability to build a Dyson swarm, a hypothetical megastructure made up of a large number of interconnected Dyson spheres.