Technological Diversity and Economics: Coupling Effects on Hydrogen Production from Biomass

This review evaluates a diverse portfolio of technologies that produce hydrogen from renewable energy sources. A number of literature surveys and efficient hydrogen formation pathways are compared. The continuous improvement in hydrogen production pathways is of crucial importance in the making of hydrogen from sustainable energy sources. Evaluation of the economics in producing hydrogen from natural gas (NG), coal, biomass, atoms, sunlight and wind shows that the key to commercialization of hydrogen energy depends on feedstock cost, raw material availability, capital costs of equipment and how long the technology has been established. Estimates reveal that the hydrogen production cost (HPC) from coal is expected to be 0.36 to 1.83 US$/kg, whereas for NG it is 2.48 to 3.17 US$/kg. Depending on the type and cost of raw material employed, the HPC from biomass is expected to be in range of 1.44 to 2.83 US$/kg, while the HPC from wind is expected to be 5.50 US$/kg depending on the size of wind turbines and type of electrolyzers used. Compared to the HPC from coal and NG, the HPC from solar energy is much more higher (by more than 3 orders of magnitude). Considering the capital cost, energy consumption and operating costs, a HPC of 8 US$/kg would be expected for the electrolysis of water. Nevertheless, if the cost of electricity is low, then it would be possible to produce hydrogen from solar and water electrolysis at a cheaper rate. This result implies that hydrogen production from coal, biomass and NG resources will be great enough to meet hydrogen demands in the near future. Of all of the current technologies employed for the yield of hydrogen from fuels, steam methane reforming (SMR) seems to be the most practical and established technology. By the SMR pathway, HPC from NG is expected to be 3.50 US$/kg and 1.25 US $/kg for small and large plant sizes, respectively, while the HPC from NG is estimated to have a cost of 6 US$/GJ. However, production technologies including thermochemical pathways such as biomass gasification, pyrolysis, and supercritical water gasification (SCWG) and biological pathways such as photosynthesis, fermentation, and biological water gas shift reactions (BWGS) are also discussed.