Erasure Economics at Data-Centre Scale: From the Landauer Floor to Practice

Erasing one bit costs at least k_B T ln 2 (Landauer's principle), 2.87e-21 J at 300 K. This paper prices real erasure against that floor using published device power and throughput figures, and scales the result to an estimated global deletion volume of 146 zettabytes for 2024 derived from IDC Global DataSphere creation (149 ZB, 2024) and retention (under 2%) figures. At the floor a year of global deletion would cost about 3,354 J; at hard-disk practice about 1.38 TWh at device level. Practice energies per bit exceed the floor by roughly ten billion to a trillion times, and the excess is engineering overhead, not thermodynamics. Model calculations are labelled SIMULATED, NOT MEASURED. The deposit includes the paper PDF, the computation script (compute.py) that produces every number in the paper, and its output (results.json).