Abstract
<jats:p>To the best of our knowledge, no published techno-economic assessment of CO2 hydrogena-tion to methanol fully accounts for India-specific cost structures, interstate transmission charges, and benchmarking of breakeven hydrogen price against a national policy target. This study presents an integrated thermodynamic and techno-economic analysis of a 100,000 t/yr green methanol plant at Dahej SEZ, Gujarat. A thermodynamic equilibrium model validated against NIST Shomate data (MAPD 2.3%) predicts 23.8% single-pass CO2 conversion at 250 °C and 50 bar under a rigorously coupled adiabatic equilibrium–energy balance; with R = 0.90 and 10% purge, overall conversion reaches 75.7%. The coupled solve reveals a substantial methanol selectivity penalty (48.75% versus a much higher isothermal estimate) arising from accelerated reverse water–gas shift activity at the ele-vated adiabatic outlet temperature (268 °C), a finding with direct implications for reactor configuration. Pinch analysis recovers 900 kW, eliminating external hot utility demand for feed preheating. At a hydrogen price of $3.50 kg–1, LCOM is $1,127 t–1 (hydrogen: 82.3% of OPEX); at a marine fuel price of $1,000 t–1, the deterministic NPV is negative (IRR not defined, payback not achieved). Monte Carlo simulation (10 000 trials) yields a mean NPV of approximately $-117 million with a 29% probability of positive NPV, and a deterministic tornado sensitivity analysis independently confirms hydrogen price and methanol price as the dominant economic drivers. For the commodity methanol market, the breakeven hydrogen price is $0.37 kg–1, lying $0.63 kg–1 below India’s NGHM 2030 target. This indicates green methanol can serve as a demand-side anchor for India’s hydrogen economy once the NGHM target is achieved. A full ISTS charge waiver reduces LCOM to $752 t–1 and improves the debt service coverage ratio from below 1.0 to 3.43, restoring project bankability. Single-variable recycle ratio analysis shows NPV improving with recycle ratio across most of the modelled range, with the conservative base-case design (R = 0.90) retaining operational margin against inert-gas accumulation and catalyst deactivation at a modest economic cost. A strategic comparison with green ammonia at equivalent scale shows green methanol achieves superior carbon intensity (−1.304 versus +0.143 t CO2 t−1 under solar electricity), established marine fuel offtake, and full domestic</jats:p>