Applications & Pathways
Techno-economic Assessment of Hydrogen-based Energy Storage Systems in Determining the Optimal Configuration of the Nuclear-renewable Hybrid Energy System
Apr 2024
Publication
Population growth and economic development have significantly increased global energy demand. Hence it has raised concerns about the increase in the consumption of fossil fuels and climate change. The present work introduced a new approach to using carbon-free energy sources such as nuclear and renewable to meet energy demand. The idea of using the Nuclear-Renewable Hybrid Energy System (N-R HES) is suggested as a leading solution that couples a nuclear power plant with renewable energy and hydrogen-based storage systems. For this purpose using a meta-heuristic method based on Newton’s laws the configuration of the N-R HES is optimized from an economic and reliability point of view. The optimal system is selected from among six cases with different subsystems such as wind turbine photovoltaic panel nuclear reactor electrolysis fuel cell and hydrogen storage tank. Furthermore the performance of hydrogen-based energy storage systems such as hightemperature electrolysis (HTE) and low-temperature electrolysis (LTE) is evaluated from technical and economic aspects. The results of this work showed that using nuclear energy to supply the base load increases the reliability of the system and reduces the loss of power supply probability to zero. More than 70 % of the power is produced by nuclear reactors which includes more than 80 % of the system costs. The key findings showed that despite HTE’s higher efficiency using LTE as a storage system in N-R HES is more cost-effective. Finally due to recent developments and the safer design of nuclear reactors they can play an important role in combination with renewable energies to support carbon-free energy sectors especially in remote areas for decades to come.
Utilization of Hydrogen and Methane as Energy Carriers with Exhaust Gas Recirculation for Sustainable Diesel Engines
May 2024
Publication
Hydrogen and methane as secondary fuels in diesel engines can be promising solutions to meet energy demand. The current study investigated the effect of the specialty gases of different compositions on diesel engine performance and exhaust gases. Four gases with various compositions of exhaust gas recirculation (Carbon monoxide Carbon dioxide and Nitrogen) and fuels (Hydrogen and Methane) were used at various mass flow rates of 10 20 and 25 LPM (liter per minute) and various engine speeds of 2000 2500 3000 and 3500 rpm (revolutions per minute). The procured results revealed that adding specialty gases improved brake thermal efficiency and power. Similarly the brake-specific fuel consumption was also massively retarded compared to diesel due to the influence of the hydrogen and methane composition. However the fuel with the higher nitrogen reported less BTE (brake thermal efficiency) and comparatively higher exhaust gas temperature owing to the higher presence of nitrogen in their composition. Regarding emissions including exhaust gas recirculation dropped the formation of pollutants efficiently compared to diesel. Among various fuels Case 1 (30 % H2 5 % CH4 5 CO2 and 60 % CO) reported the lowest emission of NOx and Case 2 (25 % H2 5 % CH4 5 CO2 30 % CO and 35 % N2) of CO and CO2 emissions. Generally specialty gases with a variable composition of exhaust gas recirculation gases can be a promising sustainable replacement for existing fossil fuels.
Machine Learning Models for the Prediction of Turbulent Combustion Speed for Hydrogen-natural Gas Spark Ignition Engines
May 2024
Publication
The work carried out in this paper focused on “Machine learning models for the prediction of turbulent combustion speed for hydrogen-natural gas spark ignition engines”. The aim of this work is to develop and verify the ability of machine learning models to solve the problem of estimating the turbulent flame speed for a spark-ignition internal combustion engine operating with a hydrogen-natural gas mixture then evaluate the relevance of these models in relation to the usual approaches. The novelty of this work is the possibility of a direct calculation of turbulent combustion speed with a good precision using only machine learning model. The obtained models are also compared to each other by considering in turn as a comparison criterion: the precision of the result calculation time and the ability to assimilate original data (which has not undergone preprocessing). An important particularity of this work is that the input variables of the machine learning models were chosen among the variables directly measurable experimentally based on the opinion of experts in combustion in internal combustion engines and not on the usual approaches to dimensionality reduction on a dataset. The data used for this work was taken from a MINSEL 380 a 380-cc single-cylinder engine. The results show that all the machine learning models obtained are significantly faster than the usual approach and Random Forest (R2: R-squared = 0.9939 and RMSE: Root Mean Square Error = 0.4274) gives the best results. With a forecasting accuracy of over 90 % both approaches can make reasonable predictions for most industrial applications such as designing engine monitoring and control systems firefighting systems simulation and prototyping tools.
Comparative Study of Different Alternative Fuel Options for Shipowners Based on Carbon Intensity Index Model Under the Background of Green Shipping Development
Nov 2024
Publication
The International Maritime Organization (IMO)’s annual operational carbon intensity index (CII) rating requires that from 1 January 2023 all applicable ships meet both technical and operational energy efficiency requirements. In this paper we conduct a comparative study of different alternative fuel options based on a CII model from the perspective of shipowners. The advantages and disadvantages of alternative fuel options such as liquefied natural gas (LNG) methanol ammonia and hydrogen are presented. A numerical example using data from three China Ocean Shipping (Group) shipping lines is analyzed. It was found that the overall attained CII of different ship types showed a decreasing trend with the increase of the ship’s deadweight tonnage. A larger ship size choice can obtain better carbon emission reduction for the carbon emission reduction investment program using alternative fuels. The recommended options of using LNG fuel and zero-carbon fuel (ammonia and hydrogen) on Route 1 and Route 3 during the study period were analyzed for the shipowners. Carbon reduction scenarios using low-carbon fuels (LNG and methanol) and zero-carbon fuels (ammonia and hydrogen) on Route 2 are in line with IMO requirements for CII.
Prediction of Efficiency, Performance, and Emissions Based on a Validated Simulation Model in Hydrogen–Gasoline Dual-Fuel Internal Combustion Engines
Nov 2024
Publication
This study explores the performance and emissions characteristics of a dual-fuel internal combustion engine operating on a blend of hydrogen and gasoline. This research began with a baseline simulation of a conventional gasoline engine which was subsequently validated through experimental testing on an AVL testbed. The simulation results closely matched the testbed data confirming the accuracy of the model with deviations within 5%. Building on this validated model a hydrogen–gasoline dual-fuel engine simulation was developed. The predictive simulation revealed an approximately 5% increase in overall engine efficiency at the optimal operating point primarily due to hydrogen’s combustion properties. Additionally the injected gasoline mass and CO2 emissions were reduced by around 30% across the RPM range. However the introduction of hydrogen also resulted in a slight reduction (~10%) in torque attributed to the lower volumetric efficiency caused by hydrogen displacing intake air. While CO emissions were significantly reduced NOx emissions nearly doubled due to the higher combustion temperatures associated with hydrogen. This research demonstrates the potential of hydrogen–gasoline dual-fuel systems in reducing carbon emissions while highlighting the need for further optimization to balance performance with environmental impact.
Assessing the Carbon Intensity of e-fuels Production in European Countries: A Temporal Analysis
Nov 2024
Publication
The transport sector heavily relies on the use of fossil fuels which are causing major environmental concerns. Solutions relying on the direct or indirect use of electricity through efuel production are emerging to power the transport sector. To ensure environmental benefits are achieved over this transition an accurate estimation of the impact of the use of electricity is needed. This requires a high temporal resolution to capture the high variability of electricity. This paper presents a previously unseen temporal analysis of the carbon intensity of e-fuels using grid electricity in countries that are members of the European Network of Transmission System Operators (ENTSO-E). It also provides an estimation of the potential load factor for producing low-carbon e-fuels according to the European Union legislative framework. This was achieved by building on top of the existing EcoDynElec tool to develop EcoDynElec_xr a python tool enabling—with an hourly time resolution—the calculation visualisation and analysis of the historical time-series of electricity mixing from the ENTSO-E. The results highlight that in 2023 very few European countries were reaching low carbon intensity for electricity that enables the use of grid electricity for the production of green electrolytic hydrogen. The methodological assumptions consider the consumption of the electricity mix instead of the production mix and the considered time step is of paramount importance and drastically impacts the potential load factor of green hydrogen production. The developed tools are released under an open-source license to ensure transparency result reproducibility and reuse regarding newer data for other territories or for other purposes.
Development of a Method for Evaluating H2-Filling Stations
Nov 2024
Publication
To expedite the development of the infrastructural expansion for hydrogen applications the research project “THEWA” was founded. Within this project the development of hydrogen-refueling stations is being advanced so that the hydrogen strategy for mobility in Germany can move forward. One development point of the project is to develop an evaluation model that recommends a concept for hydrogen-refueling stations for initial individual situations. In this work an evaluation method is developed that provides an appropriate recommendation. For this purpose basics such as the general structure of hydrogen-refueling stations their classification into functional areas and alreadyexisting evaluation methods for multi-criteria decisions are shown. The method for the evaluation of hydrogen-refueling stations will be developed in a component-based manner for which a selection of influencing factors of hydrogen-refueling stations will be explained and categorized. With the help of an expert workshop these are scaled so that the result is an evaluation method based on an expert assessment and the consideration of individual customer requirements. In addition the method is implemented in a tool so that it can be used more easily.
Hydrogen as Fuel in the Maritime Sector: From Production to Propulsion
Nov 2024
Publication
The maritime sector plays a crucial role in global trade yet its contribution to greenhouse gas emissions remains significant. The adoption of hydrogen as a clean energy solution is gaining traction to address this. This review paper delves into the opportunities and challenges of integrating hydrogen as a marine fuel. The entire hydrogen supply chain is investigated from production to end use highlighting advancements limitations and potential safety risks. Key findings reveal that while hydrogen offers promise for reducing emissions its widespread adoption requires a well-established production storage and distribution infrastructure. Challenges persist in large-scale storage transportation and bunkering particularly in addressing space limitations and ensuring safety protocols. Propulsion systems such as internal combustion engines gas turbines and fuel cells show po tential for hydrogen adoption yet further research is needed to optimize efficiency and address technical con straints. Safety considerations also appear prominently necessitating comprehensive bunkering operations and hazard management protocols. Addressing knowledge gaps is imperative for successfully integrating hydrogen as a marine fuel. Future research should focus on optimizing storage methods developing efficient propulsion systems and enhancing safety measures to enhance hydrogen utilization in the maritime sector.
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