Applications & Pathways
Linking the Power and Transport Sectors—Part 2: Modelling a Sector Coupling Scenario for Germany
Jul 2017
Publication
“Linking the power and transport sectors—Part 1” describes the general principle of “sector coupling” (SC) develops a working definition intended of the concept to be of utility to the international scientific community contains a literature review that provides an overview of relevant scientific papers on this topic and conducts a rudimentary analysis of the linking of the power and transport sectors on a worldwide EU and German level. The aim of this follow-on paper is to outline an approach to the modelling of SC. Therefore a study of Germany as a case study was conducted. This study assumes a high share of renewable energy sources (RES) contributing to the grid and significant proportion of fuel cell vehicles (FCVs) in the year 2050 along with a dedicated hydrogen pipeline grid to meet hydrogen demand. To construct a model of this nature the model environment “METIS” (models for energy transformation and integration systems) we developed will be described in more detail in this paper. Within this framework a detailed model of the power and transport sector in Germany will be presented in this paper and the rationale behind its assumptions described. Furthermore an intensive result analysis for the power surplus utilization of electrolysis hydrogen pipeline and economic considerations has been conducted to show the potential outcomes of modelling SC. It is hoped that this will serve as a basis for researchers to apply this framework in future to models and analysis with an international focus.
Cost-optimal Reliable Power Generation in a Deep Decarbonisation Future
Jul 2019
Publication
Considering the targets of the Paris agreement rapid decarbonisation of the power system is needed. In order to study cost-optimal and reliable zero and negative carbon power systems a power system model of Western Europe for 2050 is developed. Realistic future technology costs demand levels and generator flexibility constraints are considered. The optimised portfolios are tested for both favourable and unfavourable future weather conditions using results from a global climate model accounting for the potential impacts of climate change on Europe’s weather. The cost optimal mix for zero or negative carbon power systems consists of firm low-carbon capacity intermittent renewable energy sources and flexibility capacity. In most scenarios the amount of low-carbon firm capacity is around 75% of peak load providing roughly 65% of the electricity demand. Furthermore it is found that with a high penetration of intermittent renewable energy sources a high dependence on cross border transmission batteries and a shift to new types of ancillary services is required to maintain a reliable power system. Despite relatively small changes in the total generation from intermittent renewable energy sources between favourable and unfavourable weather years of 6% emissions differ up to 70 MtCO2 yr−1 and variable systems costs up to 25%. In a highly interconnected power system with significant flexible capacity in the portfolio and minimal curtailment of intermittent renewables the potential role of green hydrogen as a means of electricity storage appears to be limited.
Economic Optima for Buffers in Direct Reduction Steelmaking Under Increasing Shares of Renewable Hydrogen
Oct 2021
Publication
While current climate targets demand substantial reductions in greenhouse gas (GHG) emissions the potentials to further reduce carbon dioxide emissions in traditional primary steel-making are limited. One possible solution that is receiving increasing attention is the direct reduction (DR) technology operated either with renewable hydrogen (H2) from electrolysis or with conventional natural gas (NG). DR technology makes it possible to decouple steel and hydrogen production by temporarily using overcapacities to produce and store intermediary products during periods of low renewable electricity prices or by switching between H2 and NG. This paper aims to explore the impact of this decoupling on overall costs and the corresponding dimensioning of production and storage capacities. An optimization model is developed to determine the least-cost operation based on perfect-foresight. This model can determine the minimum costs for optimal production and storage capacities under various assumptions considering fluctuating H2 and NG prices and increasing H2 shares. The model is applied to a case study for Germany and covers the current situation the medium term until 2030 and the long term until 2050. Under the assumptions made the role of using direct reduced iron (DRI) storage as a buffer seems less relevant. DRI mainly serves as long-term storage for several weeks similar to usual balancing storage capacities. Storing H2 on the contrary is used for short-term fluctuations and could balance H2 demand in the hourly range until 2050. From an economic perspective DRI production using NG tends to be cheaper than using H2 in the short term and potential savings from the flexible operation with storages are small at first. However in the long term until 2050 NG and H2 could achieve similar total costs if buffers are used. Otherwise temporarily occurring electricity price spikes imply substantial increases in total costs if high shares of H2 need to be achieved.
New Combustion Modelling Approach for Methane-Hydrogen Fueled Engines Using Machine Learning and Engine Virtualization
Oct 2021
Publication
The achievement of a carbon-free emissions economy is one of the main goals to reduce climate change and its negative effects. Scientists and technological improvements have followed this trend improving efficiency and reducing carbon and other compounds that foment climate change. Since the main contributor of these emissions is transportation detaching this sector from fossil fuels is a necessary step towards an environmentally friendly future. Therefore an evaluation of alternative fuels will be needed to find a suitable replacement for traditional fossil-based fuels. In this scenario hydrogen appears as a possible solution. However the existence of the drawbacks associated with the application of H2 -ICE redirects the solution to dual-fuel strategies which consist of mixing different fuels to reduce negative aspects of their separate use while enhancing the benefits. In this work a new combustion modelling approach based on machine learning (ML) modeling is proposed for predicting the burning rate of different mixtures of methane (CH4 ) and hydrogen (H2). Laminar flame speed calculations have been performed to train the ML model finding a faster way to obtain good results in comparison with actual models applied to SI engines in the virtual engine model framework.
Assessment and Recommendations for a Fossil Free Future for Track Work Machinery
Oct 2021
Publication
Current railway track work machinery is mainly operated with diesel fuel. As a result track maintenance of Austrian Federal Railways (OeBB) amounts to nearly 9000 t CO2 equivalent per year according to calculations from Graz University of Technology. OeBB’s total length of railway lines only accounts for 0.56% of the world’s length of lines. This indicates huge potential for mitigating greenhouse gas emissions considering the need for track maintenance worldwide. Environmental concerns have led to the introduction of alternative drives in the transport sector. Until now R&D (Research & Development) of alternative propulsion technologies for track work machinery has been widely neglected. This paper examines the possibility of achieving zero direct emissions during maintenance and construction work in railways by switching to alternative drives. The goal is to analyze alternative propulsion solutions arising from the transport sector and to assess their applicability to track work machinery. Research results together with a calculation tool show that available battery technology is recommendable for energy demands lower than 300 kWh per construction shift. Hydrogen fuel cell technology is an alternative for energy demands higher than 800 kWh. For machinery with energy requirements in between enhancements in battery technology are necessary and desirable for the coming years.
Experimental Investigation of the Effect of Hydrogen Addition on Combustion Performance and Emissions Characteristics of a Spark Ignition High Speed Gasoline Engine
Sep 2014
Publication
Considering energy crises and pollution problems today much work has been done for alternative fuels for fossil fuels and lowering the toxic components in the combustion products. Expert studies proved that hydrogen one of the prominent alternative energy source which has many excellent combustion properties that can be used for improving combustion and emissions performance of gasoline-fuelled spark ignition (SI) engines. This article experimentally investigated the performance and emission characteristics of a high speed single cylinder SI engine operating with different hydrogen gasoline blends. For this purpose the conventional carburetted high speed SI engine was modified into an electronically controllable engine with help of electronic control unit (ECU) which dedicatedly used to control the injection timings and injection durations of gasoline. Various hydrogen enrichment levels were selected to investigate the effect of hydrogen addition on engine brake mean effective pressure (Bmep) brake thermal efficiency volumetric efficiency and emission characteristics. The test results demonstrated that combustion performances fuel consumption and brake mean effective pressure were eased with hydrogen enrichment. The experimental results also showed that the brake thermal efficiency was higher than that for the pure gasoline operation. Moreover HC and CO emissions were all reduced after hydrogen enrichment.
A Comparison of Steam Reforming Concepts in Solid Oxide Fuel Cell Systems
Mar 2020
Publication
Various concepts have been proposed to use hydrocarbon fuels in solid oxide fuel cell (SOFC) systems. A combination of either allothermal or adiabatic pre-reforming and water recirculation (WR) or anode off-gas recirculation (AOGR) is commonly used to convert the fuel into a hydrogen rich mixture before it is electrochemically oxidised in the SOFC. However it is unclear how these reforming concepts affect the electrochemistry and temperature gradients in the SOFC stack. In this study four reforming concepts based on either allothermal or adiabatic pre-reforming and either WR or AOGR are modelled on both stack and system level. The electrochemistry and temperature gradients in the stack are simulated with a one-dimensional SOFC model and the results are used to calculate the corresponding system efficiencies. The highest system efficiencies are obtained with allothermal pre-reforming and WR. Adiabatic pre-reforming and AOGR result in a higher degree of internal reforming which reduces the cell voltage compared to allothermal pre-reforming and WR. Although this lowers the stack efficiency higher degrees of internal reforming reduce the power consumption by the cathode air blower as well leading to higher system efficiencies in some cases. This illustrates that both stack and system operation need to be considered to design an efficient SOFC system and predict potentially deteriorating temperature gradients in the stack.
A Review of Hydrogen as a Fuel in Internal Combustion Engines
Sep 2021
Publication
The demand for fossil fuels is increasing because of globalization and rising energy demands. As a result many nations are exploring alternative energy sources and hydrogen is an efficient and practical alternative fuel. In the transportation industry the development of hydrogen-powered cars aims to maximize fuel efficiency and significantly reduce exhaust gas emission and concentration. The impact of using hydrogen as a supplementary fuel for spark ignition (SI) and compression ignition (CI) engines on engine performance and gas emissions was investigated in this study. By adding hydrogen as a fuel in internal combustion engines the torque power and brake thermal efficiency of the engines decrease while their brake-specific fuel consumption increase. This study suggests that using hydrogen will reduce the emissions of CO UHC CO2 and soot; however NOx emission is expected to increase. Due to the reduction of environmental pollutants for most engines and the related environmental benefits hydrogen fuel is a clean and sustainable energy source and its use should be expanded.
A Comparison between Fuel Cells and Other Alternatives for Marine Electric Power Generation
Mar 2016
Publication
The world is facing a challenge in meeting its needs for energy. Global energy consumption in the last half-century has increased very rapidly and is expected to continue to grow over the next 50 years. However it is expected to see significant differences between the last 50 years and the next. This paper aims at introducing a good solution to replace or work with conventional marine power plants. This includes the use of fuel cell power plant operated with hydrogen produced through water electrolysis or hydrogen produced from natural gas gasoline or diesel fuels through steam reforming processes to mitigate air pollution from ships.
Heat in Buildings Strategy: Achieving Net Zero Emissions in Scotland's Buildings
Oct 2021
Publication
Sets out our vision for the future of heat in buildings and the actions we are taking in the buildings sector to deliver our climate change commitments maximise economic opportunities and ensure a just transition including helping address fuel poverty.
Our Green Print: Future Heat for Everyone
Jul 2021
Publication
Green Print - Future Heat for Everyone draws together technical consumer and economic considerations to create a pioneering plan to transition 22 million UK homes to low carbon heat by 2050.<br/>Our Green Print underlines the scale of the challenge ahead acknowledging that a mosaic of low carbon heating solutions will be required to meet the needs of individual communities and setting out 12 key steps that can be taken now in order to get us there<br/>The Climate Change Committee (CCC) estimates an investment spend of £250bn to upgrade insulation and heating in homes as well as provide the infrastructure to deliver the energy.<br/>This is a task of unprecedented scale the equivalent of retro-fitting 67000 homes every month from now until 2050. In this Report Cadent takes the industry lead in addressing the challenge.
On-Board Liquid Hydrogen Cold Energy Utilization System for a Heavy-Duty Fuel Cell Hybrid Truck
Aug 2021
Publication
In this paper a kind of on-board liquid hydrogen (LH2 ) cold energy utilization system for a heavy-duty fuel cell hybrid truck is proposed. Through this system the cold energy of LH2 is used for cooling the inlet air of a compressor and the coolant of the accessories cooling system sequentially to reduce the parasitic power including the air compressor water pump and radiator fan power. To estimate the cold energy utilization ratio and parasitic power saving capabilities of this system a model based on AMESim software was established and simulated under different ambient temperatures and fuel cell stack loads. The simulation results show that cold energy utilization ratio can keep at a high level except under extremely low ambient temperature and light load. Compared to the original LH2 system without cold energy utilization the total parasitic power consumption can be saved by up to 15% (namely 1.8 kW).
Study of the Permeation Flowrate of an Innovative Way to Store Hydrogen in Vehicles
Oct 2021
Publication
With the global warming of the planet new forms of energy are being sought as an alternative to fossil fuels. Currently hydrogen (H2) is seen as a strong alternative for fueling vehicles. However the major challenge in the use of H2 arises from its physical properties. An earlier study was conducted on the storage of H2 used as fuel in road vehicles powered by spark ignition engines or stacks of fuel cells stored under high pressure inside small spheres randomly packed in an envelope tank. Additionally the study evaluated the performance of this new storage system and compared it with other storage systems already applied by automakers in their vehicles. The current study aims to evaluate the H2 leaks from the same storage system when inserted in any road vehicle parked in conventional garages and to show the compliance of these leaks with European Standards provided that an appropriate choice of materials is made. The system’s compliance with safety standards was proved. Regarding the materials of each component of the storage system the best option from the pool of materials chosen consists of aluminum for the liner of the spheres and the envelope tank CFEP for the structural layer of the spheres and Si for the microchip.
Combination of b-Fuels and e-Fuels—A Technological Feasibility Study
Aug 2021
Publication
The energy supply in Austria is significantly based on fossil natural gas. Due to the necessary decarbonization of the heat and energy sector a switch to a green substitute is necessary to limit CO2 emissions. Especially innovative concepts such as power-to-gas establish the connection between the storage of volatile renewable energy and its conversion into green gases. In this paper different methanation strategies are applied on syngas from biomass gasification. The investigated syngas compositions range from traditional steam gasification sorption-enhanced reforming to the innovative CO2 gasification. As the producer gases show different compositions regarding the H2/COx ratio three possible methanation strategies (direct sub-stoichiometric and over-stoichiometric methanation) are defined and assessed with technological evaluation tools for possible future large-scale set-ups consisting of a gasification an electrolysis and a methanation unit. Due to its relative high share of hydrogen and the high technical maturity of this gasification mode syngas from steam gasification represents the most promising gas composition for downstream methanation. Sub-stoichiometric operation of this syngas with limited H2 dosage represents an attractive methanation strategy since the hydrogen utilization is optimized. The overall efficiency of the sub-stoichiometric methanation lies at 59.9%. Determined by laboratory methanation experiments a share of nearly 17 mol.% of CO2 needs to be separated to make injection into the natural gas grid possible. A technical feasible alternative avoiding possible carbon formation in the methanation reactor is the direct methanation of sorption-enhanced reforming syngas with an overall process efficiency in large-scale applications of 55.9%.
The Implications of Ambitious Decarbonisation of Heat and Road Transport for Britain’s Net Zero Carbon Energy Systems
Oct 2021
Publication
Decarbonisation of heating and road transport are regarded as necessary but very challenging steps on the pathway to net zero carbon emissions. Assessing the most efficient routes to decarbonise these sectors requires an integrated view of energy and road transport systems. Here we describe how a national gas and electricity transmission network model was extended to represent multiple local energy systems and coupled with a national energy demand and road transport model. The integrated models were applied to assess a range of technologies and policies for heating and transport where the UK’s 2050 net zero carbon emissions target is met. Overall annual primary energy use is projected to reduce by between 25% and 50% by 2050 compared to 2015 due to ambitious efficiency improvements within homes and vehicles. However both annual and peak electricity demands in 2050 are more than double compared with 2015. Managed electric vehicle charging could save 14TWh/year in gas-fired power generation at peak times and associated emissions whilst vehicle-to-grid services could provide 10GW of electricity supply during peak hours. Together managed vehicle charging and vehicle-to-grid supplies could result in a 16% reduction in total annual energy costs. The provision of fast public charging facilities could reduce peak electricity demand by 17GW and save an estimated £650 million annually. Although using hydrogen for heating and transport spreads the hydrogen network costs between homeowners and motorists it is still estimated to be more costly overall compared to an all-electric scenario. Bio-energy electricity generation plants with carbon capture and storage are required to drive overall energy system emissions to net zero utilisation of which is lowest when heating is electrified and road transport consists of a mix of electric and hydrogen fuel-cell vehicles. The analysis demonstrates the need for an integrated systems approach to energy and transport policies and for coordination between national and local governments.
An Adaptive Renewable Energy Plant (AREP) - To Power Local Premises and Vehicles with 100% Renewables
Aug 2021
Publication
An adaptive response renewable energy plant (AREP) that provides grid balancing services and XeV station fuelling services (where “X” is any type) using renewable energy located in urban centres is described. The AREP has its own primary renewable energy sources and adapts operation in the short term to changing levels of excess or deficient energy on LV and MV electricity grids. The AREP adaptively responds by (1) storing excess energy in batteries for the short term and in hydrogen tanks after energy conversion by electrolysers for the long term; (2) returning power to the grid from either the AREP’s own primary (electron-based) energy sources or batteries and/or from hydrogen via conversion in fuel cells; (3) providing electricity for fast charging BeVs and PHeVs and hydrogen for FCeVs; and (4) exporting excess stored energy as hydrogen to domestic markets. The AREP also adapts over the long term by predictive planning of charging capacity such that the type and capacity of renewable energy equipment is optimised for future operations. A key advantage of this AREP configuration is a flexible “plug and play” capability with modular extension of energy assets. If the AREP footprint is constrained interaction with neighbouring AREPs as a mini-VPP-AREP network can assist in balancing short-term operating requirements. The benefits of this grid balancing and XeV renewable energy filling station or AREP are environmental social and economic through efficient functionality of appropriately sized components. AREPs provide a net zero emissions electricity solution to an existing network with short and long-term storage options as well as a net zero emissions fuel alternative to the transport sector while leveraging existing infrastructure with minimal upfront CAPEX. AREPs can give the flexibility a grid needs to enable high levels of renewable installations while developing green hydrogen production.
Hydrogen Blending and the Gas Commercial Framework - Report on Conclusions of NIA study
Sep 2020
Publication
Blending hydrogen into the gas grid could be an important stepping stone during the transition to a sustainable net zero system. In particular it may: provide a significant and reliable source of demand for hydrogen producers supporting the investment case for hydrogen; provide learnings and incremental change towards what could potentially become a 100% hydrogen grid; and immediately decarbonise a portion of the gas flowing through the grid. Technical questions relating to hydrogen blending are being taken forward by the industry (e.g. through the HyDeploy project in relation to the maximum potential blend of hydrogen that can be accommodated without end user appliances needing to be altered or replaced). But if blending is to take place changes to commercial arrangements will be necessary as today these assume a relatively uniform gas quality. In particular the commercial framework will need to ensure that limits on the percentage of hydrogen that can safely be blended (currently expected to be around 20% by volume) are not exceeded. We have been commissioned by Cadent to undertake a Network Innovation Allowance (NIA) project to identify the changes required to the gas commercial framework that will enable hydrogen blending in the GB gas grid and to set out a roadmap for how these can be delivered. This report sets out our recommendations.
An Evaluation of Turbocharging and Supercharging Options for High-Efficiency Fuel Cell Electric Vehicles
Dec 2018
Publication
Mass-produced off-the-shelf automotive air compressors cannot be directly used for boosting a fuel cell vehicle (FCV) application in the same way that they are used in internal combustion engines since the requirements are different. These include a high pressure ratio a low mass flow rate a high efficiency requirement and a compact size. From the established fuel cell types the most promising for application in passenger cars or light commercial vehicle applications is the proton exchange membrane fuel cell (PEMFC) operating at around 80 ◦C. In this case an electric-assisted turbocharger (E-turbocharger) and electric supercharger (single or two-stage) are more suitable than screw and scroll compressors. In order to determine which type of these boosting options is the most suitable for FCV application and assess their individual merits a co-simulation of FCV powertrains between GT-SUITE and MATLAB/SIMULINK is realised to compare vehicle performance on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle. The results showed that the vehicle equipped with an E-turbocharger had higher performance than the vehicle equipped with a two-stage compressor in the aspects of electric system efficiency (+1.6%) and driving range (+3.7%); however for the same maximal output power the vehicle’s stack was 12.5% heavier and larger. Then due to the existence of the turbine the E-turbocharger led to higher performance than the single-stage compressor for the same stack size. The solid oxide fuel cell is also promising for transportation application especially for a use as range extender. The results show that a 24-kWh electric vehicle can increase its driving range by 252% due to a 5 kW solid oxide fuel cell (SOFC) stack and a gas turbine recovery system. The WLTP driving range depends on the charge cycle but with a pure hydrogen tank of 6.2 kg the vehicle can reach more than 600 km.
Advanced Hydrogen Production through Methane Cracking: A Review
Jul 2015
Publication
Hydrogen is widely produced and used for our day-to-day needs. It has also the potential to be used as fuel for industry or can be used as an energy carrier for stationary power. Hydrogen can be produced by different processes like from fossil fuels (Steam methane reforming coal gasification cracking of natural gas); renewable resources (electrolysis wind etc.); nuclear energy (thermochemical water splitting). In this paper few processes have been discussed briefly. Cracking of methane has been given special emphasis in this review for production of hydrogen. There are mainly two types of cracking non-catalytic and catalytic. Catalytic cracking of methane is governed mainly by finding a suitable catalyst; its generation deactivation activation and filament formation for the adsorption of carbon particles (deposited on metal surface); study of metallic support which helps in finding active sites of the catalyst for the reaction to proceed easily. Non-catalytic cracking of methane is mainly based on thermal cracking. Moreover several thermal cracking processes with their reactor configurations have been discussed.
Promotion Effect of Hydrogen Addition in Selective Catalytic Reduction of Nitrogen Oxide Emissions from Diesel Engines Fuelled with Diesel-biodiesel-ethanol Blends
Nov 2021
Publication
Ethanol and palm oil biodiesel blended with diesel fuel have the potential to reduce greenhouse gas emissions such as carbon dioxide (CO2) and can gradually decrease dependence on fossil fuels. However the combustion products from these fuels such as oxides of nitrogen (NOx) total hydrocarbons (THC) and particulate matter (PM) require to be examined and any beneficial or detrimental effect to the environment needs to be assessed. This study investigates the hydrocarbon selective catalyst reduction (HC-SCR) activities by the effect of combustion using renewable fuels (biodiesel-ethanol-diesel) blends and the effect of hydrogen addition to the catalyst with the various diesel engine operating conditions. Lower values rate of heat released were recorded as the ethanol fraction increases resulting in trade-off where lower NOx was produced while greater concentration of carbon monoxide (CO) and THC was measured in the exhaust. Consequently increasing the THC/NOx promoting the NOx reduction activity (up to 43%). Additionally the HC-SCR performance was greatly heightened when hydrogen was added into the catalyst and able to improve the NOx reduction activity up to 73%. The experiment demonstrated plausible alternatives to improve the HC-SCR performance through the aids from fuel blends and hydrogen addition.
No more items...