Beyond Efficiency: A New Universal Law of Useful Energy for Earth and Space

Classical energy efficiency metrics often overestimate real-world system performance because they assume a single-stage conversion of input energy into useful output. In practice, energy must pass through multiple stages of absorption, transport, regulation, and transformation, each subject to irreversible losses governed by thermodynamic constraints. This study introduces a universal survival–conversion framework that replaces idealized efficiency with a physically grounded formulation of useful energy production. The governing law is expressed as Euseful = Ein × Ψ × Cint, where Ein represents supplied energy, Ψ denotes the energy survival factor defined as Ψ = AE / (TE + ε), and Cint represents internal…