Comment on “How green is blue hydrogen?”

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Journal Title
Journal ISSN
Volume Title
Comment/debate
Date
2022-07
Major/Subject
Mcode
Degree programme
Language
en
Pages
11
1944-1954
Series
Energy Science and Engineering, Volume 10, issue 7
Abstract
This paper is written in response to the paper “How green is blue hydrogen?” by R. W. Howarth and M. Z. Jacobson. It aims at highlighting and discussing the method and assumptions of that paper, and thereby providing a more balanced perspective on blue hydrogen, which is in line with current best available practices and future plant specifications aiming at low CO2 emissions. More specifically, in this paper, we show that: (i) the simplified method that Howarth and Jacobson used to compute the energy balance of blue hydrogen plants leads to significant overestimation of CO2 emissions and natural gas (NG) consumption and (ii) the assumed methane leakage rate is at the high end of the estimated emissions from current NG production in the United States and cannot be considered representative of all-NG and blue hydrogen value chains globally. By starting from the detailed and rigorously calculated mass and energy balances of two blue hydrogen plants in the literature, we show the impact that methane leakage rate has on the equivalent CO2 emissions of blue hydrogen. On the basis of our analysis, we show that it is possible for blue hydrogen to have significantly lower equivalent CO2 emissions than the direct use of NG, provided that hydrogen production processes and CO2 capture technologies are implemented that ensure a high CO2 capture rate, preferably above 90%, and a low-emission NG supply chain.
Description
Publisher Copyright: © 2022 The Authors. Energy Science & Engineering published by the Society of Chemical Industry and John Wiley & Sons Ltd.
Keywords
carbon capture, CCS, hydrogen, natural gas
Other note
Citation
Romano , M C , Antonini , C , Bardow , A , Bertsch , V , Brandon , N P , Brouwer , J , Campanari , S , Crema , L , Dodds , P E , Gardarsdottir , S , Gazzani , M , Jan Kramer , G , Lund , P D , Mac Dowell , N , Martelli , E , Mastropasqua , L , McKenna , R C , Monteiro , J G M S , Paltrinieri , N , Pollet , B G , Reed , J G , Schmidt , T J , Vente , J & Wiley , D 2022 , ' Comment on “How green is blue hydrogen?” ' , Energy Science and Engineering , vol. 10 , no. 7 , pp. 1944-1954 . https://doi.org/10.1002/ese3.1126