Applications & Pathways

This study investigates hydrogen (H2) as a supplementary fuel in heavy-duty diesel engines using pre-manifold injection. A H2-diesel dual-fuel (H2DF) system was implemented on a commercial class-8 heavy-duty diesel truck without modifying the original diesel injection system and engine control unit (ECU). Tests were conducted on a chassis dynamometer at engine speeds between 1000 and 1400 rpm with driver-demanded torques from 10 to 75%. The hydrogen energy fraction (HEF) was strategically controlled in the range between 10 and 30%. Overall CO2 reduction (comparable to the HEF level) was achieved with similar brake-specific energy consumption (BSEC) at all loads and speeds. To maintain the same shaft torque the driver-demanded torque was reduced in H2DF operation which resulted in a lower boost pressure. At higher loads engine-out BSNOx slightly decreased while BSCO and black carbon (BC) increased significantly due to lower oxygen concentration resulting from the lower boost pressure. At lower loads engine-out BSCO and BSBC decreased moderately while NO2/NO ratio increased substantially in H2DF operation. Deliberate air path and diesel injection control are expected to enable higher HEF and GHG reductions.

As a zero-emission fuel hydrogen provides a promising solution with significant potential to meet the increasing demand for clean energy alternatives. Hydrogen fueling stations are essential infrastructure for the commercialization of hydrogen fuel cells but the flammability of hydrogen poses safety challenges throughout its lifecycle. Past incidents highlight the need for robust risk assessments starting with comprehensive hazard identification and failure scenario analysis.<br/>This paper proposes using Multilevel Flow Modelling (MFM) a functional modeling method integrated with reasoning capability to support safety evaluations. MFM enables the structured representation of system functions and supports tasks such as fault diagnosis and hazard analysis. Previously applied in nuclear offshore and chemical systems MFM is here used to model a liquid hydrogen fueling station. This paper demonstrates that a developed MFM model identifies failure scenarios related to hydrogen leaks overpressure and operational reliability issues.<br/>This paper conducts a comparison between MFM and traditional methods FMEA and FTA and demonstrates MFM's strength in handling the key challenges rooted from complex failure interactions. Results suggest MFM is complementary to traditional methods and can enhance risk assessments. MFM also contributes to digitalization in safety assessment and monitoring systems ultimately improving hydrogen fueling station reliability and safety.

In the future steel products will be reheated for hot working using hydrogen instead of natural gas. This study investigated the differences in oxide scale formation between natural gas/air and hydrogen/air combustion at constant air-fuel-ratio. Samples of a hypo-eutectoid eutectoid and hyper-eutectoid steel grade (dimensions: 30 x 30 x 50 mm W x H x L) were exposed to the two atmospheres in a semi-industrial scale furnace for 180 min at three sample core temperatures (1100 1200 and 1280 °C). Specific mass gain was calculated and the samples were metallographically examined. Switching the fuel increased scale formation depending on the steel. The exponential correlation between temperature and scale formation is more pronounced for the eutectoid and the hyper-eutectoid steel grade. Metallographic investigations revealed similar scale morphologies in both atmospheres but with significant temperature dependence. The decarburization depth is atmosphere-independent. Thus switching fuel does not negatively impact the properties of the steel substrate; it only increases scale formation during reheating.

An analysis of the turbulent premixed combustion speed in an internal combustion engine using natural gas hydrogen and intermediate mixtures as fuels is carried out with different air-fuel ratios and engine speeds. The combustion speed has been calculated by means of a two-zone diagnosis thermodynamic model combined with a geometric model using a spherical flame front hypothesis. 48 operating conditions have been analyzed. At each test point the pressure record of 200 cycles has been processed to calculate the cycle averaged turbulent combustion speed for each flame front radius. An expression of turbulent combustion speed has been established as a function of two parameters: the ratio between turbulence intensity and laminar combustion speed and the second parameter the ratio between the integral spatial scale and the thickness of the laminar flame front increased by instabilities. The conclusion of this initial study is that the position of the flame front has a great influence on the expression to calculate the combustion speed. A unified correlation for all positions of the flame front has been obtained by adding one correction term based on the expansion speed as a turbulence source. This unified correlation is thus valid for all experimental conditions of fuel types air–fuel ratios engine speeds and flame front positions. The correlation can be used in quasi-dimensional predictive models to determine the heat released in an ICE.

This study investigated the cost competitiveness using total cost of ownership (TCO) analysis of hydrogen fuel cell electric vehicles (FCEVs) in heavy duty on and off-road fleet applications as a key enabler in the decarbonisation of the transport sector and compares results to battery electric vehicles (BEVs) and diesel internal combustion engine vehicles (ICEVs). Assessments were carried out for a present day (2021) scenario and a sensitivity analysis assesses the impact of changing input parameters on FCEV TCO. This identified conditions under which FCEVs become competitive. A future outlook is also carried out examining the impact of time-sensitive parameters on TCO when net zero targets are to be reached in the UK and EU. Several FCEVs are cost competitive with ICEVs in 2021 but not BEVs under base case conditions. However FCEVs do have potential to become competitive with BEVs under specific conditions favouring hydrogen including the application of purchase grants and a reduced hydrogen price. By 2050 a number of FCEVs running on several hydrogen scenarios show a TCO lower than ICEVs and BEVs using rapid chargers but for the majority of vehicles considered BEVs remain the lowest in cost unless specific FCEV incentives are implemented. This paper has identified key factors hindering the deployment of hydrogen and conducted comprehensive TCO analysis in heavy duty on and off-road fleet applications. The output has direct contribution to the decarbonisation of the transport sector.

This study aimed to compare hydrogen ammonia methanol and waste-derived biofuels as shipping fuels using life cycle assessment to establish what potential they have to contribute to the shipping industry’s 100% greenhouse gas emission reduction target. A novel approach was taken where the greenhouse gas emissions associated with one year of global shipping fleet operations was used as a common unit for comparison therefore allowing the potential life cycle greenhouse gas emission reduction from each fuel option to be compared relative to Paris Agreement compliant targets for international shipping. The analysis uses life cycle assessment from resource extraction to use within ships with all GHGs evaluated for a 100-year time horizon (GWP100). Green hydrogen waste-derived biodiesel and bio-methanol are found to have the best decarbonisation po tential with potential emission reductions of 74–81% 87% and 85–94% compared to heavy fuel oil; however some barriers to shipping’s decarbonisation progress are identified. None of the alternative fuels considered are currently produced at a large enough scale to meet shipping’s current energy demand and uptake of alternative fuel vessels is too slow considering the scale of the challenge at hand. The decarbonisation potential from alternative fuels alone is also found to be insufficient as no fuel option can offer the 100% emission reduction required by the sector by 2050. The study also uncovers several sensitives within the life cycles of the fuel options analysed that have received limited attention in previous life cycle investigations into alternative shipping fuels. First the choice of allocation method can potentially double the life cycle greenhouse gas emissions of e-methanol due to the carbon ac counting challenges of using waste carbon dioxide streams during fuel production. This leads to concerns related to the true impact of using carbon dioxide captured from fossil-fuelled processes to produce a combustible product due to the resultant high downstream emissions. Second nitrous oxide emissions from ammonia combustion are found to be highly sensitive due to high greenhouse gas potency potentially offsetting any greenhouse reduction potential compared to heavy fuel oil. Further uncertainties are highlighted due to limited available data on the rate of nitrous oxide production from ammonia engines. The study therefore highlights an urgent need for the shipping sector to consider these factors when investing in new ammonia and methanol engines; failing to do so risks jeopardizing the sector’s progress towards decarbonisation. Finally whilst alternative fuels can offer good decarbonisation potential (particularly waste derived biomethanol and bio-diesel and green hydrogen) this cannot be achieved without accelerated investment in new and retrofit vessels and new fuel supply chains: the research concludes that existing pipeline of vessel orders and fuel production facilities is insufficient. Furthermore there is a need to integrate alternative fuel uptake with other decarbonisation strategies such as slow steaming and wind propulsion.

With the escalating global energy demand the pursuit of sustainable energy sources has become increasingly urgent. Among these biofuels have gained significant attention for their potential to provide renewable and eco-friendly alternatives. Biodiesel is recognized for its diverse and cost-effective feedstock options. The study provides a novel approach to the production of biodiesel by employing the use of Dunaliella salina microalgae as a green source. The research suggests the blends provide a future solution to less toxic fuel sources achieving efficiency and minimizing emissions. This research emphasize on the production of biodiesel from Dunaliella salina microalgae a promising resource due to its high energy yield. The microalgae were cultivated in an f/2 nutrient medium enriched with carbon dioxide vitamins and trace metals. A total of 700 mL of bio-oil was extracted using ultrasonication at 50 Hz for 85 minutes. Then the bio-oil was transesterified in a single-stage sodium hydroxide-catalysed process with methanol as a solvent. The process yielded a high extraction efficiency of 94%. The produced biodiesel was characterized through advanced analytical techniques including NMR spectroscopy GC-MS and FTIR test studies confirming its suitability as a fuel. Combustion and emission analyses revealed that the direct substitution of biodiesel blends for diesel in engines significantly reduced hydrocarbon and carbon monoxide emissions although a slight increase in nitrogen oxide (NOx) emissions was noted. The combustion and emission characteristics were influenced by blend composition and calorific value. Additionally the study provides a detailed comparison of the performance of pure diesel biodiesel blends and hydrogen-enriched biodiesel in diesel engines offering valuable insights into their environmental and performance impacts. This study gives additional insights towards future work such as scalability (consisting large scale cultivation of algae for better studies) engine durability (studies on engine wear and tear) and integration with renewable energy sources (integrating renewable sources like solar and wind energies).

As a subdivision of the hydrogen energy application field ship-borne hydrogen fuel cell systems have certain differences from vehicle or other application scenarios in terms of their structural type safety environmental adaptability and test verification. The connection method of the ship-borne hydrogen storage cylinder (SHSC) is very important for the hydrogen fuel cell ship and the structural parameters of the SHSC are particularly important in the hydrogen refueling process. To ensure the safe and reliable operation of the hydrogen-powered ship research on the filling of the SHSC under different connection modes was carried out during refueling. In our study a thermal flow physical model of the SHSC was established to research the hydrogen refueling process of the series and parallel SHSCs. The influence of series and parallel modes of the SHSCs on the hydrogen refueling process was explored and the evolution law of the internal flow field pressure and temperature of series and parallel SHSCs under different filling parameters was analyzed by numerical simulation. Our results confirmed the superiority of the parallel modular approach in terms of thermal safety during refueling. The results can supply a technical basis for the future development of hydrogen refueling stations and ship-board hydrogenation control algorithms.

The maritime industry while indispensable to global trade is a significant contributor to greenhouse gas (GHG) emissions accounting for approximately 3% of global emissions. As international regulatory bodies particularly the International Maritime Organization (IMO) push for ambitious decarbonization targets hydrogen-based technologies have emerged as promising alternatives to conventional fossil fuels. This review critically examines the potential of hydrogen fuels—including hydrogen fuel cells (HFCs) and hydrogen internal combustion engines (H2ICEs)—for maritime applications. It provides a comprehensive analysis of hydrogen production methods storage technologies onboard propulsion systems and the associated techno-economic and regulatory challenges. A detailed life cycle assessment (LCA) compares the environmental impacts of hydrogenpowered vessels with conventional diesel engines revealing significant benefits particularly when green or blue hydrogen sources are utilized. Despite notable hurdles—such as high production and retrofitting costs storage limitations and infrastructure gaps—hydrogen holds considerable promise in aligning maritime operations with global sustainability goals. The study underscores the importance of coordinated government policies technological innovation and international collaboration to realize hydrogen’s potential in decarbonizing the marine sector.

BACKGROUND: Norway is facing the challenge of reducing transport emissions. High speed crafts(HSC) are the means of transport with highest emissions. Currently there is little literature or experienceof using hydrogen systems for HSC.OBJECTIVE: Evaluate the economic feasibility of fuel cell (FC) powered HSC vs diesel and biodieseltoday and in a future scenario based on real world operation profile.<br/>METHOD: Historical AIS position data from the route combined with the speed-power characteristicsof a concept vessel was used to identify the energy and power demand. From the resulting data a suitableFC system was defined and an economic comparison made based on annual costs including annualizedinvestment and operational costs.<br/>RESULTS: HSC with a FC-system has an annual cost of 12.6 MNOK. It is 28% and 12% more expensivethan diesel and biodiesel alternative respectively. A sensitivity analysis with respect to 7 key design pa-rameters indicates that highest impact is made by hull energy efficiency FC system cost and hydrogen fuelcost. In a future scenario (2025–2030) with moderate technology improvements and cost developmentthe HSC with FC-systems can become competitive with diesel and cheaper than biodiesel.<br/>CONCLUSIONS: HSC with FC-systems may reach cost parity with conventional diesel in the period2025–2030.