A downhole electrical power grid electrically connects a string of downhole tools including at least a first power generating tool and a second power consuming tool. The power generating tool includes a power generator, an electric load, and a power management controller. The power management controller is configured to automatically electrically connect and disconnect the tool from the power grid. The power generating tool may include a rotary steerable tool having a power generator, an electric actuator, and the aforementioned power management controller.