Publications

"The Oxford Institute for Energy Studies started researching the role of hydrogen in the energy transition in 2020.  Since then the interest in hydrogen has continued to grow globally across the energy industry. A key research question has been the extent to which clean hydrogen can be scaled up at reasonable cost and whether it can play a significant role in the global energy system. In April 2022 OIES launched a new Hydrogen Research Programme under the overarching theme of ’building business cases for a hydrogen economy’. This overarching theme was selected based on the observation that most clean hydrogen developments to date had been relatively small-scale pilot or demonstration projects typically funded by government grants or subsidies. For clean hydrogen to play a significant role there will need to be business cases developed in order to attract the many hundreds of billions of dollars of investment required  most of which will need to come from the private sector albeit ultimately underpinned by government-backed decarbonisation policies.  Just over a year has passed since the start of the Hydrogen Research Programme and the intention of this paper is to pull together key themes which have emerged from the research so far and which can form a useful framework for further research both by OIES and others.<br/>The six key themes in this paper listed below are intended to create a framework to at least start to address the challenges:<br/>Hydrogen is in competition with other decarbonisation alternatives.<br/>The business case for clean hydrogen relies on government policy to drive decarbonisation.<br/>It is essential to understand emissions associated with potential hydrogen investments.<br/>Hydrogen investments need to consider the full value chain and its geopolitics.<br/>Transport of hydrogen is expensive and so should be minimised.<br/>Storage of hydrogen is an essential part of the value chain and requires more focus.

Co-optimizing energy and water resources in a microgrid can increase efficiency and improve economic performance. Energy-water storage (EWS) devices are crucial components of a high-efficient energy-water microgrid (EWMG). The state of charge (SoC) at the end of the first day of operation is one of the most significant variables in EWS devices since it is used as a parameter to indicate the starting SoC for the second day which influences the operating cost for the second day. Hence this paper examines the benefits and applicability of a lookahead optimization strategy for an EWMG integrated with multi-type energy conversion technologies and multienergy demand response to supply various energy-water demands related to electric/hydrogen vehicles and commercial/residential buildings with the lowest cost for two consecutive days. In addition a hybrid info-gap/robust optimization technique is applied to cover uncertainties in photovoltaic power and electricity prices as a tri-level optimization framework without generating scenarios and using the probability distribution functions. Duality theory is also used to convert the problem into a single-level MILP so that it can be solved by CPLEX. According to the findings the implemented energy-water storage systems and look-ahead strategy accounted for respectively 4.03% and 0.43% reduction in the total cost.

Due to climate change there is an urgent need to decarbonize high-emission industries. As coal-based operations predominate in primary steelmaking the steel industry offers an exceptionally high potential for reducing greenhouse gas emissions. Alternative processes for almost fully decarbonized primary steelmaking exist but require substantial investments by steelmakers for their implementation while maintaining desired production levels during the transformation periods. In this context the energy carriers required change such that the transformation of the steelmaking processes is deeply intertwined with the transformation of the background system. For the first time we evaluate potential transformation pathways from the steelmakers’ perspective using a prospective life cycle assessment approach. We find that hydrogen may facilitate a reduction of direct emissions by around 96 % compared to conventional steelmaking in 2050. However indirect emissions remain at a high level throughout the transformation period unless the upstream stages of the value chain are transformed accordingly.

Following the growing use of hydrogen in the industry gas explosions have become a critical safety issue. Computational Fluid Dynamic (CFD) and in particular the Large Eddy Simulation (LES) approach have already shown their great potential to reproduce such scenarios with high fidelity. However the computational cost of this approach is an obvious limiting factor since fine grid resolutions are often required in the whole computational domain to ensure a correct numerical resolution of the deflagration front all along its propagation. In this context Adaptive Mesh Refinement (AMR) is of great interest to reduce the computational cost as it allows to dynamically refine the mesh throughout the explosion scenario only in regions where Quantities of Interest (QoI) are detected. This study aims to demonstrate the strong potential of AMR for the LES of explosions. The target scenario is a hydrogen-air explosion in the GraVent explosion channel [1]. Using the massively parallel Navier- Stokes compressible solver AVBP a reference simulation is first obtained on a uniform and static unstructured mesh. The comparison with the experiments shows a good agreement in terms of absolute flame front speed overpressure and flow visualisation. Then an AMR simulation is performed targeting the same resolution as the reference simulation only in regions where QoI are detected i.e. inside the reaction zones and vortical structures. Results show that the accuracy of the reference simulation is recovered with AMR for only 12% of its computational cost.

The use of energy in the built environment contributes to over one-third of the world’s carbon emissions. To reduce that effect two primary solutions can be adopted i.e. (i) renovation of old buildings and (ii) increasing the renewable energy penetration. This review paper focuses on the latter. Renewable energy sources typically have an intermittent nature. In other words it is not guaranteed that these sources can be harnessed on demand. Thus complement solutions should be considered to use renewable energy sources efficiently. Hydrogen is recognized as a potential solution. It can be used to store excess energy or be directly exploited to generate thermal energy. Throughout this review various research papers focusing on hydrogen-based heating systems were reviewed analyzed and classified from different perspectives. Subsequently articles related to machine learning models optimization algorithms and smart control systems along with their applications in building energy management were reviewed to outline their potential contributions to reducing energy use lowering carbon emissions and improving thermal comfort for occupants. Furthermore research gaps in the use of these smart strategies in residential hydrogen heating systems were thoroughly identified and discussed. The presented findings indicate that the semi-decentralized hydrogen-based heating systems hold significant potential. First these systems can control the thermal demand of neighboring homes through local substations; second they can reduce reliance on power and gas grids. Furthermore the model predictive control and reinforcement learning approaches outperform other control systems ensuring energy comfort and cost-effective energy bills for residential buildings.

The hydrogen combustion engine (H2 ICE) is known to be able to burn H2 producing no CO2 emissions and extremely low engine-out NOeo emissions. In this work the potential to reduce the NOeo emissions through the implementation of electric hybridization of an H2 ICE-equipped passenger car (H2 -HEV) combined with a dedicated energy management system (EMS) is discussed. Achieving a low H2 consumption and low NOeo emissions are conflicting objectives the trade-off of which depends on the EMS and can be represented as a Pareto front. The dynamic programming algorithm is used to calculate the Pareto-optimal EMS calibrations for various driving missions. Through the utilization of a dedicated energy management calibration H2 -HEVs exhibit the potential to decrease the NOeo x emissions by more than 90% while decreasing the H2 consumption by over 16% compared to a comparable non-hybridized H2 -vehicle. The present paper represents the initial potential analysis suggesting that H2 -HEVs are a viable option towards a CO2 -free mobility with extremely low NOeo emissions.

The transition to renewable energy sources to mitigate climate change will require large-scale energy storage to dampen the fluctuating availability of renewable sources and to ensure a stable energy supply. Energy storage in the geological subsurface can provide capacity and support the cycle times required. This study investigates hydrogen storage methane storage and compressed air energy storage in subsurface porous formations and quantifies potential storage capacities as well as storage rates on a site-specific basis. For part of the North German Basin used as the study area potential storage sites are identified employing a newly developed structural geological model. Energy storage capacities estimated from a volume-based approach are 6510 TWh and 24544 TWh for hydrogen and methane respectively. For a consistent comparison of storage capacities including compressed air energy storage the stored exergy is calculated as 6735 TWh 25795 TWh and 358 TWh for hydrogen methane and compressed air energy storage respectively. Evaluation of storage deliverability indicates that high deliverability rates are found mainly in two of the three storage formations considered. Even accounting for the uncertainty in geological parameters the storage potential for the three considered storage technologies is significantly larger than the predicted demand and suitable storage rates are achievable in all storage formations.

The escalating global demand for goods transport via shipping has heightened energy consumption impacting worldwide health and the environment. To mitigate this international organizations aim to achieve complete fuel desulphurization and decarbonization by 50% by 2050. Investigating eco-friendly fuels is crucial particularly those with a reduced carbon and zero sulfur content. Methanol derived mainly from renewable sources and produced by carbon dioxide’s hydrogenation method stands out as an effective solution for GHG reduction. Leveraging its favorable properties global scalability and compatibility with the existing infrastructure especially LNGs methanol proves to be a cost-efficient and minimally disruptive alternative. This review explores methanol’s role as a hybrid maritime fuel emphasizing its ecological production methods advantages and challenges in the shipping industry’s green transition. It discusses the environmental impacts of methanol use and analyzes economic factors positioning methanol not only as an ecofriendly option but also as a financially prudent choice for global shipping. Methanol is efficient and cost-effective and excels over MGO especially in new ships. It is economically advantageous with decreasing investment costs compared to LNG while providing flexibility without specialized pressure tanks. Global marine fuel trends prioritize fuel traits accessibility and environmental considerations incorporating factors like policies emissions bunkering and engine adaptability during transitions.

Hydrogen is the gas of the moment: an abundant element that can be created using renewable energy transported in gaseous or liquid form and offering the ability to provide energy with only water vapour as an emission. Hydrogen can also be used in a fuel blend in electricity generation gas turbines providing a low carbon option for providing the peak electricity to cover high demand and firming.<br/>While the electricity grid is itself transforming to decarbonising hard-to-abate industries such as cement and bauxite refineries are slower to reduce emissions constrained by their high temperature process requirements. Hydrogen offers a solution allowing onsite production process heat with waste heat recovery supporting blended gas turbine generation for onsite electricity supply.<br/>This article builds on decarbonisation pathway simulation results from an ANEM model of the electricity grid identifying the amount of peak demand energy required from gas turbines. The research then examines the quantity flow rate storage requirements and emissions reduction if this peak generation were supplied by open cycle hydrogen capable gas turbines.

Hydrogen could gradually replace fossil fuels mitigating the human impact on the environment. However equipment exposed to hydrogen is subjected to damaging effects due to H2 absorption and permeation through metals. Hence inspection activities are necessary to preserve the physical integrity of the containment systems and the risk-based (RBI) methodology is considered the most beneficial approach. This review aims to provide relevant information regarding hydrogen embrittlement its effect on materials’ properties and the synergistic interplay of the factors influencing its occurrence. Moreover an overview of predictive maintenance strategies is presented focusing on the RBI methodology. A systematic review was carried out to identify examples of the application of RBI to equipment exposed to hydrogenated environments and to identify the most active research groups. In conclusion a significant lack of knowledge has been highlighted along with difficulties in applying the RBI methodology for equipment operating in a pure hydrogen environment.