Publications

In August 2022 Shell started construction of Holland Hydrogen I (HH I) a 200 MW electrolyser plant in the port of Rotterdam’s industrial zone on Maasvlakte II in the Netherlands. HH I will produce up to 60000 kg of renewable hydrogen per day. The development and demonstration of a safe layout and plant design had been challenging due to ambitious HH I project premises many technical novelties common uncertainties in hydrogen leak effect prediction a lack of large-scale water electrolyzer operating history and limited standardization in this industry sector. This paper provides an industry perspective of the major challenges in commercial electrolyzer plant HSSE risk assessment and risk mitigation work processes required to develop and demonstrate a safe design and it describes lessons learned in this area during the HH I project. Furthermore the paper lists major common gaps in relevant knowledge engineering tools standards and OEM deliverables that need closure to enable future commercial electrolyzer plant projects to develop an economically viable and plant design and layout more efficiently and cost-effectively.

In Poland hydrogen production should be carried out using renewable energy sources particularly wind energy (as this is the most efficient zero-emission technology available). According to hydrogen demand in Poland and to ensure stability as well as security of energy supply and also the realization of energy policy for the EU it is necessary to use offshore wind energy for direct hydrogen production. In this study a centralized offshore hydrogen production system in the Baltic Sea area was presented. The goal of our research was to explore the possibility of producing hydrogen using offshore wind energy. After analyzing wind conditions and calculating the capacity of the proposed wind farm a 600 MW offshore hydrogen platform was designed along with a pipeline to transport hydrogen to onshore storage facilities. Taking into account Poland’s Baltic Sea area wind conditions with capacity factor between 45 and 50% and having obtained results with highest monthly average output of 3508.85 t of hydrogen it should be assumed that green hydrogen production will reach profitability most quickly with electricity from offshore wind farms.

The circular economy is a decisive strategy for reconciling economic development and the environment. In France the CE was introduced into the law in 2015 with the objective of closing the loop. The legislation also delegates energy policy towards the French regions by granting them the jurisdiction to directly plan the energy–climate issues on their territory and to develop local energy resources. Thereby the SUD PACA region has redefined its objectives and targeted carbon neutrality and the transition to a CE by 2050. To study this transition we developed a TIMESPACA optimization model. The results show that following a CE perspective to develop a local energy system could contribute to reducing CO2 emissions by 50% in final energy consumption and reaching almost free electricity production. To obtain greater reductions the development of the regional energy systems should follow a careful policy design favoring the transition to low energy-consuming behavior and the strategical allocation of resources across the different sectors. Biomethane should be allocated to the buildings and industrial sector while hydrogen should be deployed for buses and freight transport vehicles.

Hydrogen gas will be an essential energy carrier for global energy systems in the future. However non-renewable sources account for 96% of the production. Food wastes have high hydrogen generation potential which can positively influence global production and reduce greenhouse gas (GHG) emissions. The study evaluates the potential of food waste hydrogen-based power generation through biogas steam reforming and its environmental and economic impact in major Ghanaian cities. The results highlight that the annual hydrogen generation in Kumasi had the highest share of 40.73 kt followed by Accra with 31.62 kt while the least potential was in Tamale (3.41 kt). About 2073.38 kt was generated in all the major cities. Hydrogen output is predicted to increase from 54.61 kt in 2007 to 119.80 kt by 2030. Kumasi produced 977.54 kt of hydrogen throughout the 24-year period followed by Accra with 759.76 kt Secondi-Takoradi with 255.23 kt and Tamale with 81.85 kt. According to the current study Kumasi had the largest percentage contribution of hydrogen (47.15%) followed by Accra (36.60%) Secondi-Takoradi (12.31%) and Tamale (3.95%). The annual power generation potential in Kumasi and Accra was 73.24 GWh and 56.85 GWh. Kumasi and Accra could offset 8.19% and 6.36% of Ghana's electricity consumption. The total electricity potential of 3728.35 GWh could displace 17.37% of Ghana's power consumption. This electricity generated had a fossil diesel displacement capacity of 1125.90 ML and could reduce GHG emissions by 3060.20 kt CO2 eq. Based on the findings the total GHG savings could offset 8.13% of Ghana's carbon emissions. The cost of power generation from hydrogen is $ 0.074/kWh with an annual positive net present value of $ 658.80 million and a benefit-to-cost ratio of 3.43. The study lays the foundation and opens policy windows for sustainable hydrogen power generation in Ghana and other African countries.

In the present study Reynolds-Averaged Navier-Stokes simulations together with a novel flamelet generated manifold (FGM) hybrid combustion model incorporating preferential diffusion effects is utilised for the investigation of a hydrogen-blended diesel-hydrogen dual-fuel engine combustion process with high hydrogen energy share. The FGM hybrid combustion model was developed by coupling laminar flamelet databases obtained from diffusion flamelets and premixed flamelets. The model employed three control variables namely mixture fraction reaction progress variable and enthalpy. The preferential diffusion effects were included in the laminar flamelet calculations and in the diffusion terms in the transport equations of the control variables. The resulting model is then validated against an experimental diesel-hydrogen dual-fuel combustion engine. The results show that the FGM hybrid combustion model incorporating preferential diffusion effects in the flame chemistry and transport equations yields better predictions with good accuracy for the in-cylinder characteristics. The inclusion of preferential diffusion effects in the flame chemistry and transport equations was found to predict well several characteristics of the diesel-hydrogen dual-fuel combustion process: 1) ignition delay 2) start and end of combustion 3) faster flame propagation and quicker burning rate of hydrogen 4) high temperature combustion due to highly reactive nature of hydrogen radicals 5) peak values of the heat release rate due to high temperature combustion of the partially premixed pilot fuel spray with entrained hydrogen/air and then background hydrogen-air premixed mixture. The comparison between diesel-hydrogen dual-fuel combustion and diesel only combustion shows early start of combustion longer ignition delay time higher flame temperature and NOx emissions for dual-fuel combustion compared to diesel only combustion.

The gasification of Polish coal to produce hydrogen could help to make the country independent of oil and gas imports and assist in the rational energy transition from gray to green hydrogen. When taking strategic economic or legislative decisions one should be guided not only by the level of CO2 emissions from the production process but also by other environmental impact factors obtained from comprehensive environmental analyses. This paper presents an analysis of the life cycle of hydrogen by coal gasification and its application in a vehicle powered by FCEV cells. All the main stages of hydrogen fuel production by Shell technology as well as hydrogen compression and transport to the distribution point are included in the analyses. In total two fuel production scenarios were considered: with and without sequestration of the carbon dioxide captured in the process. Life cycle analysis was performed according to the procedures and assumptions proposed in the FC-Hy Guide Guidance Document for performing LCAs on Fuel Cells and H2 Technologies by the CML baseline method. By applying the CO2 sequestration operation the GHG emissions rate for the assumed functional unit can be reduced by approximately 44% from 34.8 kg CO2-eq to 19.5 kg CO2-eq but this involves a concomitant increase in the acidification rate from 3.64·10−2 kg SO2-eq to 3.78·10−2 kg SO2-eq in the eutrophication index from 5.18·10−2 kg PO3− 4-eq to 5.57·10−2 kg PO3− 4-eq and in the abiotic depletion index from 405 MJ to 414 MJ and from 1.54·10−5 kg Sbeq to 1.61·10−5 kg Sbeq.

Autonomous Underwater Vehicles (AUVs) are vehicles that are primarily used to accomplish oceanographic research data collection and auxiliary offshore tasks. At the present time they are usually powered by lithium-ion secondary batteries which have insufficient specific energies. In order for this technology to achieve a mature state increased endurance is required. Fuel cell power systems have been identified as an effective means to achieve this endurance but no implementation in a commercial device has yet been realized. This paper summarizes the current state of development of the technology in this field of research. First the most adequate type of fuel cell for this application is discussed. The prototypes and design concepts of AUVs powered by fuel cells which have been developed in the last few years are described. Possible commercial and experimental fuel cell stack options are analyzed examining solutions adopted in the analogous aerial vehicle applications as well as the underwater ones to see if integration in an AUV is feasible. Current solutions in oxygen and hydrogen storage systems are overviewed and energy density is objectively compared between battery power systems and fuel cell power systems for AUVs. A couple of system configuration solutions are described including the necessary lithium-ion battery hybrid system. Finally some closing remarks on the future of this technology are given.

Countries such as China are facing a bottleneck in their paths to carbon neutrality: abating emissions in heavy industries and heavy-duty transport. There are few in-depth studies of the prospective role for clean hydrogen in these ‘hard-to-abate’ (HTA) sectors. Here we carry out an integrated dynamic least-cost modelling analysis. Results show that first clean hydrogen can be both a major energy carrier and feedstock that can significantly reduce carbon emissions of heavy industry. It can also fuel up to 50% of China’s heavy-duty truck and bus fleets by 2060 and significant shares of shipping. Second a realistic clean hydrogen scenario that reaches 65.7 Mt of production in 2060 could avoid US$1.72 trillion of new investment compared with a no-hydrogen scenario. This study provides evidence of the value of clean hydrogen in HTA sectors for China and countries facing similar challenges in reducing emissions to achieve net-zero goals.

Hydrogen is the energy vector that will lead us toward a more sustainable future. It could be the fuel of both fuel cells and internal combustion engines. Internal combustion engines are today the only motors characterized by high reliability duration and specific power and low cost per power unit. The most immediate solution for the near future could be the application of hydrogen as a fuel in modern internal combustion engines. This solution has advantages and disadvantages: specific physical chemical and operational properties of hydrogen require attention. Hydrogen is the only fuel that could potentially produce no carbon carbon monoxide and carbon dioxide emissions. It also allows high engine efficiency and low nitrogen oxide emissions. Hydrogen has wide flammability limits and a high flame propagation rate which provide a stable combustion process for lean and very lean mixtures. Near the stoichiometric air–fuel ratio hydrogen-fueled engines exhibit abnormal combustions (backfire pre-ignition detonation) the suppression of which has proven to be quite challenging. Pre-ignition due to hot spots in or around the spark plug can be avoided by adopting a cooled or unconventional ignition system (such as corona discharge): the latter also ensures the ignition of highly diluted hydrogen–air mixtures. It is worth noting that to correctly reproduce the hydrogen ignition and combustion processes in an ICE with the risks related to abnormal combustion 3D CFD simulations can be of great help. It is necessary to model the injection process correctly and then the formation of the mixture and therefore the combustion process. It is very complex to model hydrogen gas injection due to the high velocity of the gas in such jets. Experimental tests on hydrogen gas injection are many but never conclusive. It is necessary to have a deep knowledge of the gas injection phenomenon to correctly design the right injector for a specific engine. Furthermore correlations are needed in the CFD code to predict the laminar flame velocity of hydrogen–air mixtures and the autoignition time. In the literature experimental data are scarce on air–hydrogen mixtures particularly for engine-type conditions because they are complicated by flame instability at pressures similar to those of an engine. The flame velocity exhibits a non-monotonous behavior with respect to the equivalence ratio increases with a higher unburnt gas temperature and decreases at high pressures. This makes it difficult to develop the correlation required for robust and predictive CFD models. In this work the authors briefly describe the research path and the main challenges listed above.

High-resolution direct numerical simulations are conducted for under-expanded cryogenic hydrogen gas jets to characterize the nearfield flow physics. The basic flow features and jet dynamics are analyzed in detail revealing the existence of four stages during early jet development namely (a) initial penetration (b) establishment of near-nozzle expansion (c) formation of downstream compression and (d) wave propagation. Complex acoustic waves are formed around the under-expanded jets. The jet expansion can also lead to conditions for local liquefaction from the pressurized cryogenic hydrogen gas release. A series of simulations are conducted with systematically varied nozzle pressure ratios and systematically changed exit diameters. The acoustic waves around the jets are found to waken with the decrease in the nozzle pressure ratio. The increase in the nozzle pressure ratio is found to accelerate hydrogen dispersion and widen the regions with hydrogen liquefaction potential. The increase in the nozzle exit diameter also widens the region with hydrogen liquefaction potential but slows down the evolution of the flow structures.