Ah that’s helpful. Numbers give a sense of scale. Thanks

Also note that 19TW is not even mostly heat but useful work: turning motors, pumping fluids or gases, generating light and sound, etc.

This is incorrect. Almost all primary energy is turned into heat eventually. Only a microscopic fraction is turned into light that escapes into space.

The stored potential energy of a concrete block on the 15th floor of a building takes a very long time to turn back into heat.