Feasibility study of renewable e-methanol production: A substitution pathway from blue to green

Producing renewable e-methanol from e-hydrogen and diverse carbon sources is an essential way for clean methanol preparation. Despite this, the technical and economic feasibility of different e-methanols has yet to be thoroughly compared, leaving the most promising pathway to achieve commercialization yet evident. This paper reports a preliminary analysis of the lifecycle greenhouse gas (GHG) emissions and costs of four renewable e-methanols with different carbon sources: bio-carbon, direct air capture (DAC), fossil fuel carbon capture (FFCC), and fossil. The results indicate that renewable e-methanol costs (4167–10250 CNY/tonne) 2–4 times the market rate of grey methanol. However, with the carbon tax and the projected decline in e-H
2
costs, blue e-methanol may initially replace diesel in inland navigation, followed by a shift from heavy fuel oil (HFO) to green e-methanol in ocean shipping. Furthermore, the e-H
2
cost and the availability of green carbon are vital factors affecting cost-effectiveness. A reduction in e-H
2
cost from 2.1 CNY/Nm
³
to 1.1 CNY/Nm
³
resulting from a transition from an annual to a daily scheduling period, could lower e-methanol costs by 1200 to 2100 CNY. This paper also provides an in-depth discussion on the challenges and opportunities associated with the various green carbon sources.