Comparative assessment of blue hydrogen from steam methane reforming, autothermal reforming, and natural gas decomposition technologies for natural gas-producing regions

Interest in blue hydrogen production technologies is growing. Some researchers have evaluated the environ-mental and/or economic feasibility of producing blue hydrogen, but a holistic assessment is still needed. Many aspects of hydrogen production have not been investigated. There is very limited information in the literature on the impact of plant size on production and the extent of carbon capture on the cost and life cycle greenhouse gas (GHG) emissions of blue hydrogen production through various production pathways. Detailed uncertainty and sensitivity analyses have not been included in most of the earlier studies. This study conducts a holistic comparative cost and life cycle GHG emissions' footprint assessment of three natural gas-based blue hydrogen production technologies - steam methane reforming (SMR), autothermal reforming (ATR), and natural gas decomposition (NGD) to address these research gaps. A hydrogen production plant capacity of 607 tonnes per day was considered. For SMR, based on the percentage of carbon capture and capture points, we considered two scenarios, SMR-52% (indicates 52% carbon capture) and SMR-85% (indicates 85% carbon capture). A scale factor was developed for each technology to understand the hydrogen production cost with a change in pro-duction plant size. Hydrogen cost is 1.22, 1.23, 2.12, 1.69, 2.36, 1.66, and 2.55 $/kg H-2 for SMR, ATR, NGD, SMR-52%, SMR-85%, ATR with carbon capture and sequestration (ATR-CCS), and NGD with carbon capture and sequestration (NGD-CCS), respectively. The results indicate that when uncertainty is considered, SMR-52% and ATR are economically preferable to NGD and SMR-85%. SMR-52% could outperform ATR-CCS when the natural gas price decreases and the rate of return increases. SMR-85% is the least attractive pathway; however, it could outperform NGD economically when CO2 transportation cost and natural gas price decrease. Hydrogen storage cost significantly impacts the hydrogen production cost. SMR-52%, SMR-85%, ATR-CCS, and NGD-CCS have scale factors of 0.67, 0.68, 0.54, and 0.65, respectively. The hydrogen cost variation with capacity shows that operating SMR-52% and ATR-CCS above hydrogen capacity of 200 tonnes/day is economically attractive. Blue hydrogen from autothermal reforming has the lowest life cycle GHG emissions of 3.91 kgCO(2)eq/kg H-2, followed by blue hydrogen from NGD (4.54 kgCO(2)eq/kg H-2), SMR-85% (6.66 kgCO(2)eq/kg H-2), and SMR-52% (8.20 kgCO(2)eq/kg H-2). The findings of this study are useful for decision-making at various levels.

Automated summary

Interest in blue hydrogen production technologies is increasing, but a comprehensive assessment is still needed. This study compares the cost and greenhouse gas emissions of three natural gas-based blue hydrogen production technologies and finds that steam methane reforming and autothermal reforming are economically preferable. The study also highlights the importance of plant size and carbon capture rate in determining the cost and emissions of blue hydrogen production.