Each block, miners create entropy by searching a 32-bit search space for a valid nonce, which is scaled by difficulty, and on the inverse a valid nonce resolves the entropy created by the number of possible microstates a block could take (unknown until mined), which is weighted by fees. The energy of the entropy generated is equal to the energy of the entropy resolved. Knowledge of this process is how we use thermodynamics/physics to deterministically measure the amount of joules within Bitcoin the system. Each block is associated with energy flowing into the system, this is the real NGU. Energy of Bitcoin in joules is increase as long as the Coinbase + Fees of the block is non-zero. You can deterministically measure the amount of energy within Bitcoin from Genesis to present without any fiat and just joules per btc or joules per Satsoshi….its just physics. In almost16 years, I’m shocked no one has done it. Everyone is stuck in the abstraction of 21M scares units.