Microwave Power Transceivers

Microwave beamed power works via two (teamed-up) components, the Microwave Power Transmitter and the Microwave Power Receiver. It is designed to facilitate the use of solar power satellites to power your vessels. Any solar powered vessel with a microwaved beamed power transmitter will transmit its power into a sort of energy network available to any ship that has line of sight to that solar power satellite (provided, of course, that the solar power satellite has line of sight to the sun!).

Any vessel with a microwave beamed power receiver can tap into this energy network and receive the power from it.

It should suffice to say that this a great way of saving weight on missions that don't need huge amounts of electrical power. That said, huge amounts of solar energy are available in low Kerbol orbits.