An international group of researchers, including UKCCSRC Director Prof Jon Gibbins, has carried out in-depth analyses of the climate impact of blue hydrogen. The study confirms that blue hydrogen, produced from natural gas and using carbon capture and storage processes, can play an essential positive role in the energy transition, when used with certain conditions.
Hydrogen: green, blue and grey
The method used to produce the hydrogen determines its environmental performance. The optimal form is green hydrogen, produced by the electrolysis of water. For hydrogen to be green, the electricity used must come from renewable sources, such as hydro, wind or solar power, which makes it close to carbon neutral. Hydrogen produced in this way is however expensive and not universally available – due to the lack of renewable electricity and electrolyser capacity.
Most hydrogen is currently grey hydrogen, produced from natural gas or other fossil fuels, which does not benefit the environment, as its production has a negative climate impact and energy is lost during conversion.
Blue hydrogen offers a compromise. Whilst it is also produced from natural gas using a process known as steam reforming, which heats and then splits the gas into hydrogen and carbon dioxide, the CO2 is not allowed to escape into the atmosphere; it is captured and stored permanently underground.
Climate impacts and blue hydrogen
The research is an in depth study into the climate impact of blue hydrogen and was led by Heriot-Watt University and the Paul Scherrer Institute (PSI) in Villigen, Switzerland and carried out with an international collaboration of researchers from different institutes. The group used specific models for detailed simulation of processes such as carbon capture in order to model the production of blue hydrogen. The results were then fed into environmental performance models in order to be able to replicate the entire production chain, from natural gas extraction to carbon capture and storage.
The evaluation of climate impacts shows a nuanced picture: whether blue hydrogen actually benefits the climate depends to a large extent on how much methane is lost on the way from the point of extraction to hydrogen production, and how effectively carbon is captured during the steam reforming of the natural gas.
High quality technology
The key to generating blue hydrogen in the most climate-friendly way is therefore to ensure a high standard of technology. Lead author of the study Christian Bauer from PSI’s Laboratory for Energy Systems Analysis, explained: “Countries such as Norway are good role models. They are already able to extract and transport the natural gas with virtually no losses and emissions of less than 0.5 percent. If almost all the CO2 emissions are captured during the reforming process and stored underground in former natural gas fields in the North Sea, for example – a solution already proven to be safe and effective over many years – then this form of blue hydrogen is almost as climate friendly as the green form.”
Read a full press release from Heriott-Watt on this study here: https://www.hw.ac.uk/news/articles/2021/blue-hydrogen-can-help-protect-the-climate.htm
View the full original publication here: https://doi.org/10.1039/D1SE01508G