Publications

Focusing on technological innovation and convergence is crucial for utilizing hydrogen energy an emerging infrastructure area. This research paper analyzes the extent of technological capabilities in a region that could accelerate the occurrence of technological convergence in the fields related to hydrogen energy through the use of triadic patents their citation information and their regional information. The results of the Bayesian spatial model indicate that the active exchange of diverse original technologies could facilitate technological convergence in the region. On the other hand it is difficult to achieve regional convergence with regard to radical technology. The findings could shed light on the establishment of an R&D strategy for hydrogen technologies. This study could contribute to the dissemination and utilization of hydrogen technologies for sustainable industrial development.

Hydrogen is believed to be the future energy carrier that will reduce environmental pollution and solve the current energy crisis especially when produced from a renewable energy source. Solar energy is a renewable source that has been commonly utilized in the production process of hydrogen for years because it is inexhaustible clean and free. Generally hydrogen is produced by means of a water splitting process mainly electrolysis which requires energy input provided by harvesting solar energy. The proposed model integrates the solar harvesting system into a conventional Rankine cycle producing electrical and thermal power used in domestic applications and hydrogen by high temperature electrolysis (HTE) using a solid oxide steam electrolyzer (SOSE). The model is divided into three subsystems: the solar collector(s) the steam cycle and an electrolysis subsystem where the performance of each subsystem and their effect on the overall efficiency is evaluated thermodynamically using first and second laws. A parametric study investigating the hydrogen production rate upon varying system operating conditions (e.g. solar flux and area of solar collector) is conducted on both parabolic troughs and heliostat fields as potential solar energy harvesters. Results have shown that heliostat-based systems were able to attain optimum performance with an overall thermal efficiency of 27% and a hydrogen production rate of 0.411 kg/s whereas parabolic trough-based systems attained an overall thermal efficiency of 25.35% and produced 0.332 kg/s of hydrogen.

In this podcast David Ledesma talks to Martin Lambert and Abdurahman Alsulaiman about the potential hydrogen import market particularly focusing on the EU which currently holds the largest and earliest hydrogen target. The podcast explores the emerging hydrogen trade market and considers numerous possibilities for its open up providing better clarity on policy statements and balance them against project announcements.

Throughout the podcast Martin and Abdulrahman delve into various key points – they shed light on the primary areas of focus for projects set to be completed by or before 2030 as well as the distinction between announcements and tangible progress such as projects currently at the Final Investment Decision stage or under construction.

Additionally they explore the EU’s role as one of the few countries to have publicly announced its requirements for hydrogen imports and its ambitious hydrogen import target. The EU is currently establishing a benchmark for the future hydrogen market. However in order for the EU to succeed in establishing future hydrogen supply lines with future trade partners it will be crucial to engage in open dialogues covering a wide range of topics.

Join us in this podcast as we uncover the potential of the hydrogen import market with a specific focus on the EU and discuss the necessary steps for its success.

The podcast can be found on their website.

Hydrogen has attracted widespread attention as a carbon-neutral energy source but developing efficient and safe hydrogen storage technologies remains a huge challenge. Recently liquid organic hydrogen carriers (LOHCs) technology has shown great potential for efficient and stable hydrogen storage and transport. This technology allows for safe and economical large-scale transoceanic transportation and long-cycle hydrogen storage. In particular traditional organic hydrogen storage liquids are derived from nonrenewable fossil fuels through costly refining procedures resulting in unavoidable environmental contamination. Biomass holds great promise for the preparation of LOHCs due to its unique carbon-balance properties and feasibility to manufacture aromatic and nitrogen-doped compounds. According to recent studies almost 100% conversion and 92% yield of benzene could be obtained through advanced biomass conversion technologies showing great potential in preparing biomass-based LOHCs. Overall the present LOHCs systems and their unique applications are introduced in this review and the technical paths are summarized. Furthermore this paper provides an outlook on the future development of LOHCs technology focusing on biomass-derived aromatic and N-doped compounds and their applications in hydrogen storage.

The European aviation sector must substantially reduce climate impacts to reach net-zero goals. This reduction however must not be limited to flight CO2 emissions since such a narrow focus leaves up to 80% of climate impacts unaccounted for. Based on rigorous life-cycle assessment and a time-dependent quantification of non-CO2 climate impacts here we show that from a technological standpoint using electricity-based synthetic jet fuels and compensating climate impacts via direct air carbon capture and storage (DACCS) can enable climate-neutral aviation. However with a continuous increase in air traffic synthetic jet fuel produced with electricity from renewables would exert excessive pressure on economic and natural resources. Alternatively compensating climate impacts of fossil jet fuel via DACCS would require massive CO2 storage volumes and prolong dependence on fossil fuels. Here we demonstrate that a European climate-neutral aviation will fly if air traffic is reduced to limit the scale of the climate impacts to mitigate.

The transportation industry’s transition to carbon neutrality is essential for addressing sustainability concerns. This study details a model for calculating the carbon footprint of the transportation sector as it progresses towards carbon neutrality. The model aims to support policymakers in estimating the potential impact of various decisions regarding transportation technology and infrastructure. It accounts for energy demand technological advancements and infrastructure upgrades as they relate to each transportation market: passenger vehicles commercial vehicles aircraft watercraft and trains. A technology roadmap underlies this model outlining anticipated advancements in batteries hydrogen storage biofuels renewable grid electricity and carbon capture and sequestration. By estimating the demand and the technologies that comprise each transportation market the model estimates carbon emissions. Results indicate that based on the technology roadmap carbon neutrality can be achieved by 2070 for the transportation sector. Furthermore the model found that carbon neutrality can still be achieved with slippage in the technology development schedule; however delays in infrastructure updates will delay carbon neutrality while resulting in a substantial increase in the cumulative carbon footprint of the transportation sector.

Pursuing net-zero emission operations in the shipping industry are quintessential for this sector to mitigate the environmental impact caused by hydrocarbon fuel combustion. Significant contributions to this are expected from the substitution of conventional marine fuels by alternative emission-free fuels with lower emission footprints. This study aims to conduct a comprehensive literature review for delineating the main characteristics of the considered alternative fuels specifically focusing on hydrogen methanol and ammonia which have recently attracted attention from both industry and academia. This study comparatively assesses the potential of using these fuels in marine engines and their subsequent performance characteristics as well as the associated environmental benefits. In addition the required storage conditions space as well as the associated costs are reviewed. Special attention is given to the safety characteristics and requirements for each alternative fuel. The results of this study demonstrate that the environmental benefits gained from alternative fuel use are pronounced only when renewable energy is considerably exploited for their production whereas the feasibility of each fuel depends on the vessel type used and pertinent storage constraints. Hydrogen ammonia and methanol are considered best-fit solutions for small scale shipping requiring minimal on-board storage. In addition the need for comparative assessments between diesel and alternative fuels is highlighted and sheds light on marine engines’ operational characteristics. Moreover using combinations of alternative and diesel fuels is identified as a direction towards decarbonisation of the maritime sector; intensifying the need for optimisation studies on marine engine design and operation. This study concludes with recommendations for future research directions thus contributing to fuel research concepts that can facilitate the shipboard use of alternative fuels.

Environmental issues related to greenhouse gas emissions are progressively pushing the transition toward fossil-free energy scenario in which renewable energies such as solar and wind power will unavoidably play a key role. However for this transition to succeed significant issues related to renewable energy storage have to be addressed. Power-to-X (PtX) technologies have gained increased attention since they actually convert renewable electricity to chemicals and fuels that can be more easily stored and transported. H2 production through water electrolysis is a promising approach since it leads to the production of a sustainable fuel that can be used directly in hydrogen fuel cells or to reduce carbon dioxide (CO2) in chemicals and fuels compatible with the existing infrastructure for production and transportation. CO2 electrochemical reduction is also an interesting approach allowing the direct conversion of CO2 into value-added products using renewable electricity. In this review attention will be given to technologies for sustainable H2 production focusing on water electrolysis using renewable energy as well as on its remaining challenges for large scale production and integration with other technologies. Furthermore recent advances on PtX technologies for the production of key chemicals (formic acid formaldehyde methanol and methane) and fuels (gasoline diesel and jet fuel) will also be discussed with focus on two main pathways: CO2 hydrogenation and CO2 electrochemical reduction.

This paper focuses on the potential use of ammonia as a carbon-free fuel and covers recent advances in the development of ammonia combustion technology and its underlying chemistry. Fulfilling the COP21 Paris Agreement requires the de-carbonization of energy generation through utilization of carbon-neutral and overall carbon-free fuels produced from renewable sources. Hydrogen is one of such fuels which is a potential energy carrier for reducing greenhouse-gas emissions. However its shipment for long distances and storage for long times present challenges. Ammonia on the other hand comprises 17.8% of hydrogen by mass and can be produced from renewable hydrogen and nitrogen separated from air. Furthermore thermal properties of ammonia are similar to those of propane in terms of boiling temperature and condensation pressure making it attractive as a hydrogen and energy carrier. Ammonia has been produced and utilized for the past 100 years as a fertilizer chemical raw material and refrigerant. Ammonia can be used as a fuel but there are several challenges in ammonia combustion such as low flammability high NOx emission and low radiation intensity. Overcoming these challenges requires further research into ammonia flame dynamics and chemistry. This paper discusses recent successful applications of ammonia fuel in gas turbines co-fired with pulverize coal and in industrial furnaces. These applications have been implemented under the Japanese ‘Cross-ministerial Strategic Innovation Promotion Program (SIP): Energy Carriers’. In addition fundamental aspects of ammonia combustion are discussed including characteristics of laminar premixed flames counterflow twin-flames and turbulent premixed flames stabilized by a nozzle burner at high pressure. Furthermore this paper discusses details of the chemistry of ammonia combustion related to NOx production processes for reducing NOx and validation of several ammonia oxidation kinetics models. Finally LES results for a gas-turbine-like swirl-burner are presented for the purpose of developing low-NOx single-fuelled ammonia gas turbine combustors.

The investment in hydrogen-refueling stations (HRS) is key to the development of a hydrogen economy. This paper focuses on the decision-making for potential investors faced with the thought-provoking question of when the optimal timing to invest in HRS is. To fill the gap that exists due to the fact that few studies explain why HRS investment timing is critical we expound that earlier investment in HRS could induce the first mover advantages of the technology diffusion theory. Additionally differently from the previous research that only considered that HRS investment is just made by one individual firm we innovatively examine the HRS co-investment made by two different firms. Accordingly we compare these two optional investment modes and determine which is better considering either independent investment or co-operative investment. We then explore how the optimal HRS investment timing could be figured out under conditions of uncertainty with the real options approach. Given the Chinese HRS case under the condition of demand uncertainty the hydrogen demand required for triggering investment is viewed as the proxy for investment timing. Based on analytical and numerical results we conclude that one-firm independent investment is better than two-firm cooperative investment to develop HRS not only in terms of the earlier investment timing but also in terms of the attribute for dealing with the uncertainty. Finally we offer recommendations including stabilizing the hydrogen demand for decreasing uncertainty and accelerating firms’ innovation from both technological and strategic perspectives in order to ensure firms can make HRS investments on their own.