Applications & Pathways

The maritime industry is a major source of greenhouse gas (GHG) emissions largely due to ships running on fossil fuels. Transitioning to hydrogen-powered marine transportation in the Mediterranean Sea requires the development of a network of hydrogen refueling stations across the region to ensure a steady supply of green hydrogen. This paper explores the technoeconomic viability of harnessing wave energy from the Mediterranean Sea to produce green hydrogen for hydrogenpowered ships. Four promising island locations—near Sardegna Galite Western Crete and Eastern Crete—were selected based on their favorable wave potential for green hydrogen production. A thorough analysis of the costs associated with wave power facilities and hydrogen production was conducted to accurately model economic viability. The techno-economic results suggest that with anticipated cost reductions in wave energy converters the levelized cost of hydrogen could decrease to as low as 3.6 €/kg 4.3 €/kg 5.5 €/kg and 3.9 €/kg for Sardegna Galite Western Crete and Eastern Crete respectively. Furthermore the study estimates that in order for the hydrogen-fueled ships to compete effectively with their oil-fueled counterparts the levelized cost of hydrogen must drop below 3.5 €/kg. Thus despite the competitive costs further measures are necessary to make hydrogen-fueled ships a viable alternative to conventional diesel-fueled ships.

The growing concern about climate change and the contemporary increase in mobility requirements call for faster cheaper safer and cleaner means of transportation. The retrofitting of fossil-fueled piston engine ultralight aerial vehicles to hydrogen power systems is an option recently proposed in this direction. The goal of this investigation is a comparative analysis of the environmental impact of conventional and hydrogen-based propulsive systems. As a case study a hybrid electric configuration consisting of a fuel cell with a nominal power of about 30 kW a 6 kWh LFP battery and a pressurized hydrogen vessel is proposed to replace a piston prop configuration for an ultralight aerial vehicle. Both power systems are modeled with a backward approach that allows the efficiency of the main components to be evaluated based on the load and altitude at every moment of the flight with a time step of 1 s. A typical 90 min flight mission is considered for the comparative analysis which is performed in terms of direct and indirect emissions of carbon dioxide water and pollutant substances. For the hydrogen-based configuration two possible strategies are adopted for the use of the battery: charge sustaining and charge depleting. Moreover the effect of the altitude on the parasitic power of the fuel cell compressor and consequently on the net efficiency of the fuel cell system is taken into account. The results showed that even if the use of hydrogen confines the direct environmental impact to the emission of water (in a similar quantity to the fossil fuel case) the indirect emissions associated with the production transportation and delivery of hydrogen and electricity compromise the desired achievement of pollutant-free propulsion in terms of equivalent emissions of CO2 and VOCs if hydrogen is obtained from natural gas reforming. However in the case of green hydrogen from electrolysis with wind energy the total (direct and indirect) emissions of CO2 can be reduced up to 1/5 of the fossil fuel case. The proposed configuration has the additional advantage of eliminating the problem of lead which is used as an additive in the AVGAS 100LL.

Fuel cell-battery electric drivetrains are attractive alternatives to reduce the shipping emissions. This research focuses on emission-free cargo vessels and provides insight on the design lifetime operation and costs of hydrogen-hybrid systems which require further research for increased utilization. A representative round trip is created by analysing one-year operational data based on load ramps and power frequency. A low-pass filter controller is employed for power distribution. For the lifetime cost analysis 14 scenarios with varying capital and operational expenses were considered. The Net Present Value of the retrofitted fuel cell-battery propulsion system can be up to $ 2.2 million lower or up to $ 18.8 million higher than the original diesel mechanical configuration highly dependent on the costs of green hydrogen and carbon taxes. The main propulsion system weights and volumes of the two versions are comparable but the hydrogen tank (68 tons 193 m3 ) poses significant design and safety challenges.

The pressing global challenge of climate change necessitates a concerted effort to limit greenhouse gas emissions particularly carbon dioxide. A critical pathway is to replace fossil fuel sources by electrification including transportation. While electrification of light-duty vehicles is rapidly expanding the heavy-duty vehicle sector is subject to challenges notably the logistical drawbacks of the size and weight of high-capacity batteries required for range as well as the time for battery charging. This Perspective highlights the potential of hydrogen fuel-cell vehicles as a viable alternative for heavy-duty road transportation. We evaluate the implications of hydrogen integration into the freight economy energy dynamics and CO2 mitigation and envision a roadmap for a holistic energy transition. Our critical opinion presented in this Perspective is that federal incentives to produce hydrogen could foster growth in the nascent hydrogen economy. The pathway that we propose is that initial focus on operators of large fleets that could control their own fueling infrastructure. This opinion was formed from private discussions with numerous stakeholders during the formation of one of the awarded hydrogen hubs if they focus on early adopters that could leverage the hydrogen supply chain.

The rapid growth of global aviation emissions has significantly impacted the environment leading to an urgent need to use carbon reduction methods. This paper analyzes global aviation’s carbon dioxide (CO2) N2O and CH4 emission changes under different hydrogen energy application paths. The global warming potential over a 100-year period (GWP100) method is used to convert the emissions of N2O and CH4 into CO2-equivalent. Here we report the results: if the global aviation industry begins using hydrogen turbine engines by 2040 it could reduce cumulative CO2-equivalent emissions by 2.217E+10 tons by 2080 which is 2.12% higher than starting hydrogen fuel cell engines in 2045. However adopting hydrogen fuel cell engines 10 years earlier shows greater reduction capabilities than hydrogen turbine engines achieving an accumulated reduction of 3.006E+10 tons of CO2-equivalent emissions. Therefore the timing of adoption notably affects hydrogen fuel cell engines more than hydrogen turbine engines. Delaying adoption makes hydrogen fuel cell engines’ performance lag hydrogen turbine engines.

This study addresses the challenge of decarbonizing highly energy-intensive Industrial Port Areas (IPA) focusing on emissions from various sources like ship traffic warehouses buildings cargo handling equipment and hardto-abate industry typically hosted in port areas. The analysis and proposal of technological solutions and their optimal integration in the context of IPA is a topic of growing scientific interest with considerable social and economic implications. Representing the main novelties of the work this study introduces (i) the development of a novel IPA energy and green hydrogen hub located in a tropical region (Singapore); (ii) a multi-objective optimization approach to analyse synthesize and optimize the design and operation of the hydrogen and energy hub with the aim of supporting decision-making for decarbonization investments. A sensitivity analysis identifies key parameters affecting optimization results indicating that for large hydrogen demands imported ammonia economically outperforms other green hydrogen carriers. Conversely local hydrogen production via electrolysis becomes economically viable when the capital cost of alkaline electrolyser drops by at least 30 %. Carbon tax influences the choice of green hydrogen but its price variation mainly impacts system operation rather than design. Fuel cells and batteries are not considered economically feasible solutions in any scenario.

The desire to maintain CO2 concentrations in the global atmosphere implies the need to introduce ’new’ energy carriers for transport applications. Therefore the operational consumption of each such potential medium in the ’natural’ exploitation of vehicles must be assessed. A useful assessment method may be the vehicle’s energy footprint resulting from the theory of cumulative fuel consumption presented in the article. Using a (very modest) database of long-term use of hydrogen-powered cars the usefulness of this method was demonstrated. Knowing the energy footprint of vehicles of a given brand and type and the statistical characteristics of the footprint elements it is also possible to assess vehicle fleets in terms of energy demand. The database on the use of energy carriers such as hydrogen in the long-term operation of passenger vehicles is still relatively modest; however as it has been shown valuable data can be obtained to assess the energy demand of vehicles of a given brand and type. Access to a larger operational database will allow for wider use of the presented method.

Accelerating the transition to a cleaner global energy system is essential for tackling the climate crisis and green hydrogen energy systems hold significant promise for integrating renewable energy sources. This paper offers a thorough evaluation of green hydrogen’s potential as a groundbreaking alternative to achieve near-zero greenhouse gas (GHG) emissions within a renewable energy framework. The paper explores current technological options and assesses the industry’s present status alongside future challenges. It also includes an economic analysis to gauge the feasibility of integrating green hydrogen providing a critical review of the current and future expectations for the levelized cost of hydrogen (LCOH). Depending on the geographic location and the technology employed the LCOH for green hydrogen can range from as low as EUR 1.12/kg to as high as EUR 16.06/kg. Nonetheless the findings suggest that green hydrogen could play a crucial role in reducing GHG emissions particularly in hard-to-decarbonize sectors. A target LCOH of approximately EUR 1/kg by 2050 seems attainable in some geographies. However there are still significant hurdles to overcome before green hydrogen can become a cost-competitive alternative. Key challenges include the need for further technological advancements and the establishment of hydrogen policies to achieve cost reductions in electrolyzers which are vital for green hydrogen production.

The increase in the feasibility of hydrogen-based generation makes it a promising addition to the realm of renewable energies that are being employed to address the issue of electric vehicle charging. This paper presents technical and an economical approach to evaluate a newer off-grid hybrid PV-hydrogen energy-based recharging station in the city of Jamshoro Pakistan to meet the everyday charging needs of plug-in electric vehicles. The concept is designed and simulated by employing HOMER software. Hybrid PV-hydrogen and PV-hydrogenbattery are the two different scenarios that are carried out and compared based on their both technical as well as financial standpoints. The simulation results are evident that the hybrid PV- hydrogen-battery energy system has much more financial and economic benefits as compared with the PV-hydrogen energy system. Moreover it is also seen that costs of energy from earlier from hybrid PV-hydrogen-battery is more appealing i.e. 0.358 $/kWh from 0.412 $/kWh cost of energy from hybrid PV-hydrogen. The power produced by the hybrid PV- hydrogen - battery energy for the daily load demand of 1700 kWh /day consists of two powers produced independently by the PV and fuel cells of 87.4 % and 12.6 % respectively.

The aim of this mini-review is to compare the effectiveness and potential of solar cells and hydrogen fuel technologies in clean energy generation. Key aspects such as efficiency scalability environmental footprint and technological maturity are examined. Solar cells are analyzed for their ability to convert sunlight into electricity efficiently and their potential for widespread deployment with minimal environmental impact. Hydrogen fuel technologies are assessed based on their efficiency in hydrogen production scalability and overall environmental footprint from production to end use. The review identifies significant challenges including high costs infrastructure needs and policy requirements as well as opportunities for innovation and market growth. The findings provide insights to guide decision-making towards a sustainable energy future.