Applications & Pathways
Comprehensive Analysis of the Operation of an Internal Combustion Engine Fueled by Hydrogen-containing Mixtures
Mar 2023
Publication
At present hydrogen is considered as one of the most promising motor fuels capable of replacing traditional hydrocarbons. This article presents the results of a comprehensive experimental study of the effect of hydrogen additives on the main parameters of a gasoline spark-ignition ICE. The thermophysical parameters of the processes of ignition and combustion inside the cylinder with the addition of hydrogen in the amount of 0%–20% of the air volume as well as the fuel and energy characteristics of the engine and its impact on the environment were studied. It has been established that hydrogen leads to significant changes in the engine operation. It increases some parameters and reduces others improving or worsening them compared to running on pure gasoline. So with a 20% H2 addition at an average engine load the following parameters increase: the maximum pressure in the cylinder by almost 20%; the rate of pressure increase in the combustion chamber by 2.8 times; the highest combustion temperature by 140 K. At the same time the following parameters decrease: average indicator pressure by 18%; ignition timing by 82% (6◦ to TDC versus 34◦ for gasoline); crank angle corresponding to the maximum pressure by 32% (9.4◦ versus 13.9◦ for gasoline); crank angle corresponding to maximum temperature by 54% (17.7◦ after TDC versus 38.3◦ for clean gasoline); ignition delay time (τind = 0.32 ms) and visible combustion time (τvis = 1.58 ms) by 4 and 2.3 times respectively.
Optimized Design and Control of an Off Grid solar PV/hydrogen Fuel Cell Power System for Green Buildings
Sep 2017
Publication
Modelling simulation optimization and control strategies are used in this study to design a stand-alone solar PV/Fuel Cell/Battery/Generator hybrid power system to serve the electrical load of a commercial building. The main objective is to design an off grid energy system to meet the desired electric load of the commercial building with high renewable fraction low emissions and low cost of energy. The goal is to manage the energy consumption of the building reduce the associate cost and to switch from grid-tied fossil fuel power system to an off grid renewable and cleaner power system. Energy audit was performed in this study to determine the energy consumption of the building. Hourly simulations modelling and optimization were performed to determine the performance and cost of the hybrid power configurations using different control strategies. The results show that the hybrid off grid solar PV/Fuel Cell/Generator/Battery/Inverter power system offers the best performance for the tested system architectures. From the total energy generated from the off grid hybrid power system 73% is produced from the solar PV 24% from the fuel cell and 3% from the backup Diesel generator. The produced power is used to meet all the AC load of the building without power shortage (<0.1%). The hybrid power system produces 18.2% excess power that can be used to serve the thermal load of the building. The proposed hybrid power system is sustainable economically viable and environmentally friendly: High renewable fraction (66.1%) low levelized cost of energy (92 $/MWh) and low carbon dioxide emissions (24 kg CO2/MWh) are achieved.
Research on the Flexibility Margin of an Electric–Hydrogen Coupling Energy Block Based on Model Predictive Control
Apr 2022
Publication
Hydrogen energy plays an important role in the transformation of low-carbon energy and electric–hydrogen coupling will become a typical energy scenario. Aiming at the operation flexibility of a low-carbon electricity–hydrogen coupling system with high proportion of wind power and photovoltaic this work studies the flexibility margin of an electricity–hydrogen coupling energy block based on model predictive control. By analyzing the power exchange characteristics of heterogeneous energy the homogenization models of various heterogeneous energy sources are established. According to the analysis of power system flexibility margin three dimensions of flexibility margin evaluation indexes are defined from the dimension of system operation and an electricity–hydrogen coupling energy block scheduling model is established. The model predictive control algorithm is used to optimize the power balance operation of the electro–hydrogen coupling energy block and the flexibility margin of the energy block is quantitatively analyzed and calculated. Through the example analysis it is verified that the calculation method proposed in this article can not only realize the online power balance optimization of the electric–hydrogen coupling energy block but also effectively quantify the operation flexibility margin of the electric–hydrogen coupling energy block.
Review of Energy Portfolio Optimization in Energy Markets Considering Flexibility of Power-to-X
Mar 2023
Publication
Power-to-X is one of the most attention-grabbing topics in the energy sector. Researchers are exploring the potential of harnessing power from renewable technologies and converting it into fuels used in various industries and the transportation sector. With the current market and research emphasis on Power-to-X and the accompanying substantial investments a review of Power-to-X is becoming essential. Optimization will be a crucial aspect of managing an energy portfolio that includes Power-to-X and electrolysis systems as the electrolyzer can participate in multiple markets. Based on the current literature and published reviews none of them adequately showcase the state-of-the-art optimization algorithms for energy portfolios focusing on Power-to-X. Therefore this paper provides an in-depth review of the optimization algorithms applied to energy portfolios with a specific emphasis on Power-to-X aiming to uncover the current state-of-the-art in the field.
Well-To-Wheels Analysis of Future Automotive Fuels and Powertrains in the European Context
Jun 2014
Publication
The Well-to-Tank study describes the process of producing transporting manufacturing and distributing a number of fuels suitable for road transport powertrains. It covers all steps from extracting capturing or growing the primary energy carrier to refuelling the vehicles with the finished fuel.
A Multicriteria Modeling Approach for Evaluating Power Generation Scenarios Under Uncertainty: The Case of Green Hydrogen in Greece
Oct 2023
Publication
Clean energy technological innovations are widely acknowledged as a prerequisite to achieving ambitious longterm energy and climate targets. However the optimal speed of their adoption has been parsimoniously studied in the literature. This study seeks to identify the optimal intensity of moving to a green hydrogen electricity sector in Greece using the OSeMOSYS energy modeling framework. Green hydrogen policies are evaluated first on the basis of their robustness against uncertainty and afterwards against conflicting performance criteria and for different decision-making profiles towards risk by applying the VIKOR and TOPSIS multi-criteria decision aid methods. Although our analysis focuses exclusively on the power sector and compares different rates of hydrogen penetration compared to a business-as-usual case without considering other game-changing innovations (such as other types of storage or carbon capture and storage) we find that a national transition to a green hydrogen economy can support Greece in potentially cutting at least 16 MtCO2 while stimulating investments of EUR 10–13 bn. over 2030–2050.
Analysis of Power to Gas Technologies for Energy Intensive Industries in European Union
Jan 2023
Publication
Energy Intensive Industries (EII) are high users of energy and some of these facilities are extremely dependent on Natural Gas for processing heat production. In European countries where Natural Gas is mostly imported from external producers the increase in international Natural Gas prices is making it difficult for some industries to deliver the required financial results. Therefore they are facing complex challenges that could cause their delocalization in regions with lower energy costs. European countries lack on-site Natural Gas resources and the plans to reduce greenhouse gas emissions in the industrial sector make it necessary to find an alternative. Many different processes cannot be electrified and in these cases synthetic methane is one of the solutions and also represents an opportunity to reduce external energy supply dependency. This study analyzes the current development of power-to-gas technological solutions that could be implemented in large industrial consumers to produce Synthetic Methane using Green Hydrogen as a raw source and using Renewable Energy electricity mainly produced with photovoltaic or wind energy. The study also reviews the triple bottom line impact and the current development status and associated costs for each key component of a power-to-gas plant and the requirements to be fulfilled in the coming years to develop a cost-competitive solution available for commercial use.
Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight
Dec 2022
Publication
This study explored the applications of liquid hydrogen (LH2 ) in aerospace projects followed by an investigation into the efficiency of ramjets scramjets and turbojets for hypersonic flight and the impact of grey blue and green hydrogen as an alternative to JP-7 and JP-8 (kerosene fuel). The advantage of LH2 as a propellant in the space sector has emerged from the relatively high energy density of hydrogen per unit volume enabling it to store more energy compared to conventional fuels. Hydrogen also has the potential to decarbonise space flight as combustion of LH2 fuel produces zero carbon emissions. However hydrogen is commonly found in hydrocarbons and water and thus it needs to be extracted from these molecular compounds before use. Only by considering the entire lifecycle of LH2 including the production phase can its sustainability be understood. The results of this study compared the predicted Life Cycle Assessment (LCA) emissions of the production of LH2 using grey blue and green hydrogen for 2030 with conventional fuel (JP-7 and JP-8) and revealed that the total carbon emissions over the lifecycle of LH2 were greater than kerosene-derived fuels.
Combustion Characteristics of Hydrogen in a Noble Gas Compression Ignition Engine
Jul 2021
Publication
Hydrogen eliminates carbon emissions from compression ignition (CI) engines while noble gases eliminate nitrogen oxide (NOx) emissions by replacing nitrogen. Noble gases can increase the in-cylinder temperature during the compression stroke due to their high specific heat ratio. This paper aims to find the optimum parameters for hydrogen combustion in an argon–oxygen atmosphere and to study hydrogen combustion in all noble gases providing hydrogen combustion data with suitable engine parameters to predict hydrogen ignitability under different conditions. Simulations are performed with Converge CFD software based on the Yanmar NF19SK direct injection CI (DICI) engine parameters. The results are validated with the experimental results of hydrogen combustion in an argon–oxygen atmosphere with a rapid compression expansion machine (RCEM) and modifications of the hydrogen injection timing and initial temperature are proposed. Hydrogen ignition in an argon atmosphere is dependent on a minimum initial temperature of 340 K but the combustion is slightly unstable. Helium and neon are found to be suitable for hydrogen combustion in low compression ratio (CR) engines. However krypton and xenon require temperature modification and a high CR for stable ignition. Detailed parameter recommendations are needed to improve hydrogen ignitability in conventional diesel engines with the least engine modification.
Investment Timing Analysis of Hydrogen-Refueling Stations and the Case of China: Independent or Co-Operative Investment?
Jun 2023
Publication
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.
Combined Ammonia Recovery and Solid Oxide Fuel Cell Use at Wastewater Treatment Plants for Energy and Greenhouse Gas Emission Improvements
Feb 2019
Publication
Current standard practice at wastewater treatment plants (WWTPs) involves the recycling of digestate liquor produced from the anaerobic digestion of sludge back into the treatment process. However a significant amount of energy is required to enable biological breakdown of ammonia present in the liquor. This biological processing also results in the emission of damaging quantities of greenhouse gases making diversion of liquor and recovery of ammonia a noteworthy option for improving the sustainability of wastewater treatment. This study presents a novel process which combines ammonia recovery from diverted digestate liquor for use (alongside biomethane) in a solid oxide fuel cell (SOFC) system for implementation at WWTPs. Aspen Plus V.8.8 and numerical steady state models have been developed using data from a WWTP in West Yorkshire (UK) as a reference facility (750000p.e.). Aspen Plus simulations demonstrate an ability to recover 82% of ammoniacal nitrogen present in digestate liquor produced at the WWTP. The recovery process uses a series of stripping absorption and flash separation units where water is recovered alongside ammonia. This facilitates effective internal steam methane as a case of study has the potential to make significant impacts energetically and environmentally; findings suggest the treatment facility could transform from a net consumer of electricity to a net producer. The SOFC has been demonstrated to run at an electrical efficiency of 48% with NH3 contributing 4.6% of its power output. It has also been demonstrated that 3.5 kg CO2e per person served by the WWTP could be mitigated a year due to a combination of emissions savings by diversion of ammonia from biological processing and lifecycle emissions associated with the lack of reliance on grid electricity.
Source-to-sink Efficiency of Blue and Green District Heating and Hydrogen-based Heat Supply Systems
Apr 2022
Publication
Hydrogen is commonly mentioned as a future proof energy carrier. Hydrogen supporters 6 advocate for repurposing existing natural gas grids for a sustainable hydrogen supply. While the 7 long-term vision of the hydrogen community is green hydrogen the community acknowledges that 8 in the short term it will be to large extent manufactured from natural gas but in a decarbonized 9 way giving it the name blue hydrogen. While hydrogen has a role to play in hard to decarbonize 10 sectors its role for building heating demands is doubtful as mature and more energy efficient alter- 11 natives exist. As building heat supply infrastructures built today will operate for the decades to 12 come it is of highest importance to ensure that the most efficient and sustainable infrastructures are 13 chosen. This paper compares the source to sink efficiencies of hydrogen-based heat supply system 14 to a district heating system operating on the same primary energy source. The results show that a 15 natural gas-based district heating could be 267% more efficient and consequently have significantly 16 lower global warming potential than a blue hydrogen-based heat supply A renewable power-based 17 district heating could achieve above 440% higher efficiency than green hydrogen-based heat supply 18 system.
Optimal Sizing of Storage Elements for a Vehicle Based on Fuel Cells, Supercapacitors, and Batteries
Mar 2019
Publication
To achieve a vehicle-efficient energy management system an architecture composed of a PEM fuel cell as the main energy source and a hybrid storage system based on battery banks and supercapacitors is proposed. This paper introduces a methodology for the optimal component sizing aiming at minimizing the total cost achieving a cheaper system that can achieve the requirements of the speed profiles. The chosen vehicle is an urban transport bus which must meet the Buenos Aires Driving Cycle and the Manhattan Driving Cycle. The combination of batteries and supercapacitors allows a better response to the vehicle’s power demand since it combines the high energy density of the batteries with the high power density of the supercapacitors allowing the best absorption of energy coming from braking. In this way we address the rapid changes in power without reducing the global efficiency of the system. Optimum use of storage systems and fuel cell is analyzed through dynamic programming.
Techno-Economic Model for Scaling up of Hydrogen Refueling Stations
Oct 2022
Publication
In a recent publication the Hydrogen Council states that scaling up to greater production volumes leads to significant cost savings as a consequence of the industrialization of equipment manufacturing increased utilization standardization and improvements in system efficiency and flexibility. In this study a component-oriented techno-economic model is applied to five different European hydrogen refueling stations within the 3Emotion project which is planned to ensure capacities sufficient for increasing a fleet to 100 fuel cell buses. The investigation of the various cases shows that the levelized cost of hydrogen (LCOH) for large-scale applications will be in the range of about 4 €/kg to 7 €/kg within the boundaries analyzed. On-site production facilities were found to be the lower-cost design benefiting from the high volumes at stake and the economy of scale with respect to decentralized production due to the significant costs associated with retail hydrogen and transport. This study also illustrates the effects on the LCOH of varying the hydrogen delivery and production prices using a sensitivity analysis. The results show that by utilizing high-capacity trailers the costs associated with delivery could be reduced by 30%. Furthermore green hydrogen production could be a competitive solution if coupled with low electricity prices resulting in an LCOH between 4.21 €/kg and 6.80 €/kg.
Retrofitting Towards a Greener Marine Shipping Future: Reassembling Ship Fuels and Liquefied Natural Gas in Norway
Dec 2021
Publication
The reduction of greenhouse gas emissions has entered regulatory agendas in shipping. In Norway a debate has been ongoing for over a decade about whether liquefied natural gas (LNG) ship fuel enables or impedes the transition to a greener future for shipping. This paper explores the assembling of ship fuel before and after the introduction of a controversial carbon tax on LNG. It reconstructs how changes in the regulatory apparatus prompted the reworking of natural gas into a ship fuel yet later slowed down the development of LNG in a strategy to promote alternative zero-emission fuels such as hydrogen. Following ship fuel as socio-materiality in motion we find that fossil fuels are reworked into new modes of application as part of transition policies. Natural gas continues to be enacted as an “enabler of transition” in the context of shipping given that current government policies work to support the production of hydrogen from natural gas and carbon capture and storage (CCS). New modes of accounting for emissions reassemble existing fossil fuel materiality by means of CCS and fossil-based zero-emission fuels. We examine retrofit as a particular kind of reassembling and as a prism for studying the politics of fuel and the relation between transitions and existing infrastructures.
Everything About Hydrogen Podcast: Digging into the Mining Industry
Jan 2021
Publication
On this episode of Everything About Hydrogen Jan Klawitter Head of International Policy for Anglo American speaks with Andrew Chris and Patrick about Anglo American's strategy for decarbonizing its mining operations and how they plan to use hydrogen and fuel cell technologies as a key part of their approach.
The podcast can be found on their website
The podcast can be found on their website
Hydrogen Fuel for Future Mobility: Challenges and Future Aspects
Jul 2022
Publication
Nowadays the combustion of fossil fuels for transportation has a major negative impact on the environment. All nations are concerned with environmental safety and the regulation of pollution motivating researchers across the world to find an alternate transportation fuel. The transition of the transportation sector towards sustainability for environmental safety can be achieved by the manifestation and commercialization of clean hydrogen fuel. Hydrogen fuel for sustainable mobility has its own effectiveness in terms of its generation and refueling processes. As the fuel requirement of vehicles cannot be anticipated because it depends on its utilization choosing hydrogen refueling and onboard generation can be a point of major concern. This review article describes the present status of hydrogen fuel utilization with a particular focus on the transportation industry. The advantages of onboard hydrogen generation and refueling hydrogen for internal combustion are discussed. In terms of performance affordability and lifetime onboard hydrogen-generating subsystems must compete with what automobile manufacturers and consumers have seen in modern vehicles to date. In internal combustion engines hydrogen has various benefits in terms of combustive properties but it needs a careful engine design to avoid anomalous combustion which is a major difficulty with hydrogen engines. Automobile makers and buyers will not invest in fuel cell technology until the technologies that make up the various components of a fuel cell automobile have advanced to acceptable levels of cost performance reliability durability and safety. Above all a substantial advancement in the fuel cell stack is required.
Comprehensive Analysis of the Combustion of Low Carbon Fuels (Hydrogen, Methane and Coke Oven Gas) in a Spark Ignition Engine through CFD Modeling
Nov 2021
Publication
The use of low carbon fuels (LCFs) in internal combustion engines is a promising alternative to reduce pollution while achieving high performance through the conversion of the high energy content of the fuels into mechanical energy. However optimizing the engine design requires deep knowledge of the complex phenomena involved in combustion that depend on the operating conditions and the fuel employed. In this work computational fluid dynamics (CFD) simulation tools have been used to get insight into the performance of a Volkswagen Polo 1.4L port-fuel injection spark ignition engine that has been fueled with three different LCFs coke oven gas (COG) a gaseous by-product of coke manufacture H2 and CH4. The comparison is made in terms of power pressure temperature heat release flame growth speed emissions and volumetric efficiency. Simulations in Ansys® Forte® were validated with experiments at the same operating conditions with optimal spark advance wide open throttle a wide range of engine speed (2000–5000 rpm) and air-fuel ratio (λ) between 1 and 2. A sensitivity analysis of spark timing has been added to assess its impact on combustion variables. COG with intermediate flame growth speed produced the greatest power values but with lower pressure and temperature values at λ = 1.5 reducing the emissions of NO and the wall heat transfer. The useful energy released with COG was up to 16.5% and 5.1% higher than CH4 and H2 respectively. At richer and leaner mixtures (λ = 1 and λ = 2) similar performances were obtained compared to CH4 and H2 combining advantages of both pure fuels and widening the λ operation range without abnormal combustion. Therefore suitable management of the operating conditions maximizes the conversion of the waste stream fuel energy into useful energy while limiting emissions.
Climate Change Impacts of E-fuels for Aviation in Europe Under Present-day Conditions and Future Policy Scenarios
Jan 2023
Publication
‘E-fuels’ or ‘synthetic fuels’ are hydrocarbon fuels synthesized from hydrogen (H2) and carbon dioxide (CO2) where H2 can be produced via electrolysis of water or steam reforming of natural gas and CO2 is captured from the combustion of a fossil or biogenic source or directly from the atmosphere. E-fuels are drop-in substitutes for fossil fuels but their climate change mitigation benefits are largely unclear. This study evaluates the climate change impacts of e-fuels for aviation by combining different sources of CO2 and H2 up to 2050 under two contrasting policy scenarios. The analysis includes different climate metrics and the effects of near-term climate forcers which are particularly relevant for the aviation sector. Results are produced for European average conditions and for Poland and Norway two countries with high and low emission intensity from their electricity production mix. E-fuels can either have higher or lower climate change impacts than fossil fuels depending on multiple factors such as in order of importance the electricity mix the origin of CO2 the technology for H2 production and the electrolyzer efficiency. The climate benefits are generally higher for e-fuels produced from CO2 of biogenic origin while e-fuels produced from CO2 from direct air capture or fossil fuel combustion require countries with clean electricity to outperform fossil fuels. Synthetic fuels produced from H2 derived from natural gas have higher impacts than fossil fuels even when coupled with carbon capture and storage if CO2 is sourced from fossil fuels or the atmosphere. Climate change impacts of e-fuels improve in the future and they can all achieve considerable climate change mitigation in 2050 relative to fossil jet fuel provided that strict climate policy measures are implemented to decarbonize the electricity sector. Under reduced policy efforts future climate impacts in 2050 of e-fuels from atmospheric or fossil CO2 are still higher than those of fossil jet fuels with an average European electricity mix. This study shows the conditions to maximize the climate change mitigation benefits of e-fuels which essentially depend on progressive decarbonization of the electricity sector and on reduced use of CO2 sourced from fossil fuels.
Heat Pumps for Space Heating and Domestic Hot Water Production in Residential Buildings, an Environmental Comparison in a Present and Future Scenario
Nov 2022
Publication
The hydrogen vector stands as a potentially important tool to achieve the decarbonization of the energy sector. It represents an option to store the periodic excesses of energy generation from renewable electrical sources to be used as it is as a substitute for fossil fuels in some applications or reconverted into electricity when needed. In this context hydrogen can significantly decarbonize the building sector as an alternative fuel for gas-driven devices. Along with hydrogen the European strategic vision indicates the electrification of heat among the main energy transition pathways. The potential environmental benefits achievable from renewable hydrogen in thermally-driven appliances and the electrification of residential heat through electric heat pumps were evaluated and compared in this work. The novelty of the research consists of a consequential comparative life cycle assessment (16 impact categories) evaluation for three buildings (old old retrofitted and new) supplied by three different appliances (condensing boiler gas absorption heat pump and electric heat pump) never investigated before. The energy transition was evaluated for 2020 and 2030 scenarios considering the impact of gaseous fuels (natural gas and European green hydrogen) and electricity based on the pathway of the European electricity grid (27 European member states plus the United Kingdom). The results allowed to compare the environmental profile in deterministic and stochastic approaches and confirm if the increase of renewables reduces the impact in the operational phase of the appliances. The results demonstrate that despite the increased renewable share the use phase remains the most significant for both temporal scenarios contributing to 91% of the environmental profile. Despite the higher footprint in 2020 compared to the electric heat pump (198–200 vs. 170–196 gCO2eq/kWhth) the gas absorption heat pump offered a lower environmental profile than the others in all the scenarios analyzed.
No more items...