International Journal of Hydrogen Energy,
Volume 36, Issue 15, July 2011, Pages 9382–9395. Bishop, J.D.K., Axon, C.J., Banister, D., Bonilla, D., Tran, M. and McCulloch, M.D. (2011)View
Through time, the overall hydrogen production process has become more energy efficient at the expense of greater emissions per MJ delivered to the tank. The best-in-class pathway is that with the lowest greenhouse gas emissions per MJ hydrogen delivered and represents the state-of-the-art. Overall, the best-in-class pathway combination for providing hydrogen is by electricity from renewables via electrolysis.