What is one of the two primary energy sources sustaining the heat engine of convection?
Answer
Residual heat from Earth's formation
One primary contributor is the residual heat left over from the Earth's formation approximately 4.5 billion years ago, which continues to be lost from the interior, particularly across the core-mantle boundary.

#Videos
Mantle Convection explained by Peter Bunge - YouTube
Related Questions
What process is mantle convection fundamentally responsible for driving?How is the basic function of mantle convection often compared?What causes mantle material to ascend toward the surface during convection?What is one of the two primary energy sources sustaining the heat engine of convection?Which elements contribute to internal heat via radioactive decay?Which depth often separates the upper and lower mantle in the historical two-layer convection model?What flow model is suggested by current seismic evidence as the dominant regime today?How slow is the typical flow velocity of rock within a single mantle convection cycle?What role do subducting oceanic slabs play at convergent boundaries?According to the conceptual table, which force component driving plate motion is estimated to have the highest relative strength?What mechanism, besides thermal buoyancy, helps organize convective flow patterns below the plates?