Analysis of Hydrogen Production Methods Using the Analytic Hierarchy Process

Abstract

The ever-growing evidence of climate emergency continues to drive the need for innovative solutions to reduce the release of anthropogenic harmful gases. Continuing to heavily rely on energy originating from fossil fuels remains non-sustainable owing to their limited, exhausting supplies, dependence on politically insecure sources and adverse environmental impacts. These considerations, coupled with the current desperate need for energy security, have driven research towards finding cleaner alternatives. Hydrogen has the potential to reduce 5Gt of CO2 emissions annually, create 30 million new jobs and power over 400 million cars by 2050. However, for hydrogen to be justified and to be successful in feeding the world's appetite for energy, its full life cycle, including its production methods, is required to be safe, efficient, affordable and environmentally benign. This paper aims to review the status of the potential hydrogen production methods that have strong eligibility within the UK and facilitate the much-required wider discussion around hydrogen by employing a multi-disciplinary approach. The analytic hierarchy process (AHP) has been employed to allow for pairwise comparisons of decision criteria and ranks decision alternatives using expert knowledge. Six hydrogen production methods (Green Electrolysis, SMR, ATR, POX, Anaerobic Digestion and Gasification) were chosen for review against nine parameters to determine which hydrogen production method(s) present most viable for the UK to aid in decarbonising the energy system. Collating performance scores against relevant parameters from industry experts allowed for a non-bias, holistic view of the production methods. Green electrolysis was found to be the better method (score 131) when assessed against all but one parameter, resulting in the method being considered the most viable option for the UK, however, considerations are to be made for electrolyser longevity and cost. SMR scored second most viable option (score 125), however, despite presenting as an effective production method for the UK based on the performance scores, this does not reflect the current deployment or construction rate of SMR with CCS projects in the UK. ATR (score 114) and POX (score 116) carry similar characteristics and subsequently scored similarly in performance scores. Anaerobic digestion (score 104) and gasification (score 101) scored amongst the lowest as their challenge is to scale in order to reach government goals as set out in the Government Hydrogen Strategy.