SMR produces a hydrogen rich gas that is typically on the order of 70-75% hydrogen on a dry
mass basis, along with smaller amounts of methane (2-6%), carbon monoxide (7-10%), and
carbon dioxide (6-14%) (Hirschenhofer et al., 2000). Costs of hydrogen from SMR vary with
feedstock cost, scale of production, and other variables and range from about $2-5 per kilogram
at present (delivered and stored at high pressure) (NAS/NAE, 2004). Delivered costs as low as
about $1.60 per kilogram are believed to be possible in the future based on large centralized
production and pipeline delivery, and delivered costs for small-scale decentralized production
are projected to be on the order of $2.00-2.50 per kilogram (EIA, 2008; NAS/NAE, 2004).
Gasification of Coal and Other Hydrocarbons
In the partial oxidation (POX) process, also known more generally as “gasification,” hydrogen
can be produced from a range of hydrocarbon fuels, including coal, heavy residual oils, and
other low-value refinery products. The hydrocarbon fuel is reacted with oxygen in a less than
stoichiometric ratio, yielding a mixture of carbon monoxide and hydrogen at 1200° to 1350°C.
Hydrogen can be produced from coal gasification at delivered costs of about $2.00-2.50 per
kilogram at present at large scale, with delivered costs as low as about $1.50 per kilogram
believed to be possible in the future (NAS/NAE, 2004). Hydrogen can also be produced through
pyrolysis-based hydrocarbon gasification processes in the absence of oxygen, with similar
estimated delivered costs at large scale (NAS/NAE, 2004).