Blue, green, and turquoise pathways for minimizing hydrogen production costs from steam methane reforming with CO₂ capture

Rising climate change ambitions require large-scale clean hydrogen production in the near term. “Blue” hydrogen from conventional steam methane reforming (SMR) with pre-combustion CO₂ capture can fulfil this role. This study therefore presents techno-economic assessments of a range of SMR process configurations to minimize hydrogen production costs. Results showed that pre-combustion capture can avoid up to 80% of CO₂ emissions cheaply at 35 €/ton, but the final 20% of CO₂ capture is much more expensive at a marginal CO₂ avoidance cost around 150 €/ton. Thus, post-combustion CO₂ capture should be a better solution for avoiding the final 20% of CO₂. Furthermore, an advanced heat integration scheme that recovers most of the steam condensation enthalpy before the CO₂ capture unit can reduce hydrogen production costs by about 6%. Two hybrid hydrogen production options were also assessed. First, a “blue-green” hydrogen plant that uses clean electricity to heat the reformer achieved similar hydrogen production costs to the pure blue configuration. Second, a “blue-turquoise” configuration that replaces the pre-reformer with molten salt pyrolysis for converting higher hydrocarbons to a pure carbon product can significantly reduce costs if carbon has a similar value to hydrogen. In conclusion, conventional pre-combustion CO₂ capture from SMR is confirmed as a good solution for kickstarting the hydrogen economy, and it can be tailored to various market conditions with respect to CO₂, electricity, and pure carbon prices.