Derek Buzasi (Florida Gulf Coast University) has suggested that Hot Jupiter planets use an external power source to help heat them.
This means a planet receiving and converting extra energy from the electromagnetic plasma and fields from its local Star and Solar system.
Much like the earth does from our Sun through solar plasma wind as seen in our auroras, FTE (Flux Transfer Event) and the stunning spacequakes (that have a similar signature to earthquakes!) and whatever other power sources we will discover in the future.
Does the Earths global electric circuit, combined with the electromagnetic energy from our Sun and the Solar system help provide the energy needed to expand the earth?
Expanding Earth energy mystery - article links
How to Toast a Planet (Sky & Telescope)
Stellar Magnetic Fields as a Heating Source for Extrasolar Giant Planets (Abstract from Derek Buzasi paper)
Earth's global electric circuit (National Science Foundation)
Why Does Saturn Radiate Twice The Energy It Absorbs From The Sun? (Science 2.0)
What Planet Gives Off 2 Times as Much Heat as it Receives From the Sun? (Seattle pi)
Flux Transfer Event - Magnetic Portals Connect Earth to the Sun (NASA)
Spacequakes Rumble Near Earth (NASA)
The Earth's Electrical Environment (free pdf from National Academy of Sciences)
Earths electric weather circuit (everythingselectric.com)
Auroras from “Space Tornadoes” (Sky & Telescope)
Space tornadoes power the atmosphere of the Sun (Phys.org)