If we owe everything we are to energy from the sun,?

Question

what fuels the tectonic movement of the plates? will this heat source last forever? what will happen when it stops? is it renewable or non-renewable?

Answer 1

To add to the other answers:

When the Earth cools sufficiently, the plates will stop moving and volcanism will cease. Most of the surficial gasses on the Earth will be blown away by the sun. The Earth will end up looking a lot like Mars.

The Earth's internal energy source (nuclear decay) is non-renewable. At some point in the future it will no longer produce heat.

However, as stated previously, this will take many billions of years, and Earth may be a part of the sun by then. It certainly won't happen during our lifetimes.

Answer 2

Heat from the interior of the Earth causes convection currents within the asthenosphere (upper mantle).  These convection currents move the tectonic plates.

The heat that drives the convection currents does not come from the sun.

The Earth's internal heat source provides the energy for our dynamic planet, supplying it with the driving force for plate-tectonic motion, and for on-going catastrophic events such as earthquakes and volcanic eruptions. This internal heat energy was much greater in the early stages of the Earth than it is today, having accumulated rapidly by heat conversion associated with three separate processes, all of which were most intense during the first few hundred thousand years of the Earth's history: (1) extraterrestrial impacts, (2) gravitational contraction of the Earth's interior, and (3) the radioactive decay of unstable isotopes.

The earth is still young enough to be heated by the decay of radioactive elements.  Estimates are that the earth formed about 4.6 billion years ago.  Plenty of natural radioactive isotopes have persisted from that time to the present.  The most important are Thorium-232, Uranium-235, and Uranium-238, but there are many more.

This internal heat will not last forever but it will last for an extremely long time.  This heat is not renewable.

No one knows for sure what will happen when the Earth has no more internal heat.

Answer 3

Tectonic activity is driven by convection currents in the molten core of the earth and the semi-molten magma in the mantle.  This heat is leftover from the beginning of the solar system.  When the earth was formed it was entirely molten.  As the crust cooled, it solidified into rock, but the crust only forms a thin layer on the outside of a squishy ball, and it is broken up into large plates that can still move around.  

The earth continues to cool and the crust slowly gets thicker.  At some point the crust will become thick enough to stop moving around.  But this may not happen before the sun burns out.