Net-negative emission methanol from direct air capture and water electrolysis: A comprehensive analysis of multiple energy pathways

[Geoengineering News]

https://www.sciencedirect.com/science/article/pii/S2212982026002180

Authors: Karina Anaya, Jubil Joy, Amit Kumar

24 July 2026

Abstract 

Deep decarbonization requires pathways that remove CO 2 and convert it into products, yet published DAC-electrolysis-methanol studies often assume simplified CO 2 /H 2 inputs and rarely compare dispatchable energy supplies under consistent techno-economic and cradle-to-gate greenhouse-gas boundaries. Here, a bottom-up analysis integrates direct air capture (DAC), alkaline water electrolysis (AWE), and CO 2 hydrogenation to methanol, and evaluates three energy-supply configurations: grid or renewable electricity with natural gas process heat (scenario 1); integration of an Allam cycle supplied with electrolytic oxygen from AWE to provide on-site power and additional CO 2 (scenario 2); and on-site electricity and heat from high-temperature gas-cooled reactors (scenario 3). Carbon pricing and uncertainty analysis are performed. Each case includes a 1 Mt-CO 2 /y potassium hydroxide (KOH)-calcium (Ca) looping DAC unit, and methanol capacity varies with available CO 2 sources. In scenario 1, CO 2 is supplied by DAC and natural gas combustion associated with process heat and electricity generation, yielding 2610 t-MeOH/d. In scenario 2, CO 2 is supplied by DAC and the Allam cycle, yielding 4471 t-MeOH/d. In scenario 3, fossil fuels are eliminated and CO 2 is supplied only by DAC, yielding 2207 t-MeOH/d. Energy consumption is 40.5, 42.2, and 98.5 GJ/t-MeOH for scenarios 1, 2, and 3, respectively. Scenario 3 achieves the lowest cradle-to-gate GHG intensity (-1.52 t-CO 2 /t-MeOH), while fossil-dominant grids yield 4.13 and 3.69 t-CO 2 /t-MeOH in scenarios 1 and 2. Methanol cost ranges from $590 to $1413/t, $655 to $1326/t, and $921/t for scenarios 1, 2, and 3, respectively, with break-even carbon prices of $36.47–$150.31/t-CO 2 (scenario 1), $53.80–$168.55/t-CO 2 (scenario 2), and $88.05/t-CO 2 (scenario 3).

Source: ScienceDirect