Optimisation of green hydrogen energy-vector systems under climate uncertainty

Anthropogenic greenhouse gas (GHG) emissions have already exacted a large cost on billions of people globally through increased frequency and severity of extreme weather events and environmental degradation (Intergovernmental Panel On Climate Change 2023; Newman and Noy 2023). GHG emissions continue to rise, with 2022 marking a new maximum. Continuing on this trajectory, the already severe impacts of climate change will intensify.

Urgent change is needed to decarbonize industry and lifestyles globally. Green ammonia could present an opportunity for rapid decarbonisation of multiple global systems. This project aims to deliver further research required to assess the feasibility and competitiveness of green ammonia as an energy vector.

Hydrocarbon-derived ammonia has been used as a key ingredient of nitrogenous fertiliser and other industries for over 100-years. In the last decade research and investment has been building in ammonia from electrolysis-derived green hydrogen (green ammonia), not only to decarbonize the fertiliser industry but also considering ammonia as a potential green fuel or energy vector (Valera-Medina and Banares-Alcantara 2021).

In particular, with the International Maritime Organisation having agreed 2050 net-zero targets, interest in green ammonia as a fuel for shipping has increased, as techno-economic modelling shows it should be cheaper than hydrogen for use at large scales and distances given the cost of compressing hydrogen (Cui and Aziz 2023). Green ammonia is also less limited in scale-up potential than carbon-based green fuels such as biomethane as it does not require land-intensive carbon feedstock.

Over the past two years our team has developed a detailed techno-economic model of green ammonia supply for shipping (publication pending). I aim to build on the techno-economic modelling work developed in (Salmon and Bañares-Alcántara 2022) to create a multi-fuel energy system model, and use this to study optimal decarbonised energy systems under climate uncertainty.

To my knowledge, no publicly available spatially-explicit model exists of an energy system satisfying a set of given energy demand profiles for specific applications and optimising across energy delivery methods including direct electrical, battery and green hydrogen, ammonia, methane and methanol. Including evaluations of climate uncertainty in the modelling will be key in determining the most resilient energy-delivery mix.

Shipping provides a single-sector example of the type of question I aim to answer: accounting for overall demand and system resilience, what is the degree of penetration hydrogen should have compared to ammonia for shipping fuel? Will it be more efficient to run local shipping on hydrogen while longer distance shipping runs on ammonia? This work will provide additional insights for decarbonising the shipping sector, and be extendable to applications for energy demand of other transport and industrial sectors, informing policy for the energy transition.

The current work of the group is already leading to projects with the Global Maritime Forum, the UK Department for Transport and other stakeholders. We expect these collaborations to continue in the evolution of the DPhil. This research description is an expansion of the original proposed title Effect of Climate Change on the Offshore Wind Production of Green Ammonia. This project falls within the EPSRC Building a green future research area.

Cui, Jinyue, and Muhammad Aziz. 2023. 'Techno-Economic Analysis of Hydrogen Transportation Infrastructure Using Ammonia and Methanol'. International Journal of Hydrogen Energy 48 (42): 15737-47. https://doi.org/10.1016/j.ijhydene.2023.01.096.

Intergovernmental Panel On Climate Change. 2023. Climate Change 2021 - The Physical Science Basis: Working Group I Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. 1st ed. Cambridge University Press. https://doi.org/10.1017/9781009157896