ICL team assesses relative costs of carbon mitigation for 12 H2 production paths; trade-off between cost and level of decarbonization
A team at Imperial College London has examined the relative costs of carbon mitigation from a lifecycle perspective for 12 different hydrogen production techniques using fossil fuels, nuclear energy and renewable sources. An open-access paper on their work is published the RSC journal Energy & Environmental Science.
As with all comparisons between fossil routes and renewables, cost and emissions data are frequently misused by advocates of all parties to push policy-makers and public opinion further along the polarizing debate of the role of fossil fuels in a low-carbon system. The best approach to decarbonizing hydrogen supply at least cost is not to champion or demonize specific technologies, but to jointly provide evidence to policy-makers to support higher levels of climate ambition.
Ultimately, the development of low-CO2, large-scale and economically competitive hydrogen production processes is fundamental to the production of low-carbon fuels, fertilizers and other petrochemicals. To achieve this, there is a significant amount of research going on to improve the performance of existing methods and to find new promising routes to generate hydrogen.—Parkinson et al.
Their results show a trade-off between the cost of mitigation and the proportion of decarbonization achieved. The most cost-effective methods of decarbonization still utilize fossil feedstocks due to their low cost of extraction and processing, but only offer moderate decarbonization levels due to previous underestimations of supply chain emissions contributions.
Proportional reduction in emissions against percentage cost increase relative to SMR. The variability of emissions and cost parameters shown reflect the full ranges of emissions and costs values used in the study. Biomass with CCS, emissions reduction of 213% and a cost increase of 168%, has been omitted from the chart as an outlier to allow focus on other technologies. Parkinson et al.
Methane pyrolysis may be the most cost-effective short-term abatement solution, but its emissions reduction performance is heavily dependent on managing supply chain emissions while cost effectiveness is governed by the price of solid carbon.
Renewable electrolytic routes offer significantly higher emissions reductions, but production routes are more complex than those that utilize naturally-occurring energy-dense fuels and hydrogen costs are high at modest renewable energy capacity factors.
Nuclear routes are highly cost-effective mitigation options, but could suffer from regionally varied perceptions of safety and concerns regarding proliferation and the available data lacks depth and transparency.
They note that better-performing fossil-based hydrogen production technologies with lower decarbonization fractions will be required to minimize the total cost of decarbonization but may not be commensurate with ambitious climate targets.
For the study, they parameterized and re-estimated production costs and life cycle emissions from currently available assessments to produce robust ranges to describe uncertainties for each technology.
They compared hydrogen production pathways using a combination of metrics, levelized cost of carbon mitigation and the proportional decarbonization benchmarked against steam methane reforming to provide a clearer picture of the relative merits of various hydrogen production pathways, the limitations of technologies and the research challenges that need to be addressed for cost-effective decarbonization pathways.
B. Parkinson, P. Balcombe, J. F. Speirs, A. Hawkes and K. Hellgardt (2019) “Levelized Cost of CO2 Mitigation from Hydrogen Production Routes” Energy Environ. Sci., doi: 10.1039/C8EE02079E