Explain the energy source that powers the volcanoes of Io.

Tidal forces generated by the Jupiter's gravitational pull

Explanation:

The most active volcanic body in the entire solar system is the volcanoes of the Io. And the volcanoes are active due to the heat energy leading to the melting of the rocks and particles beneath.

The major source for the Io volcano, that provides the power (or the heat) is the tidal forces generated by the Jupiter's gravitational pull.