Applications & Pathways

Hydrogen addition can improve the performance and extend the lean burn limit of gasoline engines. Different hydrogen injection strategies lead to different types of hydrogen mixture distribution (HMD) which affects the engine performance. Therefore the present study experimentally investigated the effects of hydrogen injection strategy on the combustion and emissions of a hydrogen/gasoline dual-fuel port-injection engine under lean-burn conditions. Four different hydrogen injection strategies were explored: hydrogen direct injection (HDI) forming a stratified hydrogen mixture distribution (SHMD); hydrogen intake port injection forming a premixed hydrogen mixture distribution (PHMD); split hydrogen direct injection (SHDI) forming a partially premixed hydrogen mixture distribution (PPHMD); and no hydrogen addition (NHMD). The results showed that 20% hydrogen addition could extend the lean burn limit from 1.5 to 2.8. With the increase in the excess air ratio the optimum HMD changed from PPHMD to SHMD. The maximum brake thermal efficiency was obtained with an excess air ratio of 1.5 with PPHMD. The coefficient of variation (COV) with NHMD was higher than that with hydrogen addition since the hydrogen enhanced the stability of ignition and combustion. The engine presented the lowest emissions with PHMD. There were almost no carbon monoxide (CO) and nitrogen oxides (NOx) emissions when the excess air ratio was respectively more than 1.4 and 2.0.

Urban population and the trend towards online commerce leads to an increase in delivery solution in cities. The growth of the transport sector is very harmful to the environment being responsible for approximately 40% of greenhouse gas emissions in the European Union. The problem is aggravated when transporting perishable foodstuffs as the vehicle propulsion engine (VPE) must power not only the vehicle but also the refrigeration unit. This means that the VPE must be running continuously both on the road and stationary (during delivery) as the cold chain must be preserved. The result is costly (high fuel consumption) and harmful to the environment. At present refrigerated transport does not support full-electric solutions due to the high energy consumption required which motivates the work presented in this article. It presents a turnkey solution of a hydrogen-powered refrigeration system (HPRS) to be integrated into standard light trucks and vans for short-distance food transport and delivery. The proposed solution combines an air-cooled polymer electrolyte membrane fuel cell (PEMFC) a lithium-ion battery and low-weight pressurised hydrogen cylinders to minimise cost and increase autonomy and energy density. In addition for its implementation and integration all the acquisition power and control electronics necessary for its correct management have been developed. Similarly an energy management system (EMS) has been developed to ensure continuity and safety in the operation of the electrical system during the working day while maximizing both the available output power and lifetime of the PEMFC. Experimental results on a real refrigerated light truck provide more than 4 h of autonomy in intensive intercity driving profiles which can be increased if necessary by simply increasing the pressure of the stored hydrogen from the current 200 bar to whatever is required. The correct operation of the entire HPRS has been experimentally validated in terms of functionality autonomy and safety; with fuel savings of more than 10% and more than 3650 kg of CO2/ year avoided.

While electrification of light duty vehicles is becoming a real solution to abate local pollutant as well as greenhouse gases emission heavy duty applications (such as long distance freight and maritime transport) will keep requiring fuel-based propulsion systems. In these sectors dominated by compression ignition engines research on alternative biofuels and new combustion modes is still highly necessary. Dual-fuel combustion appears as a very promising concept to replace conventional diesel fuel by sustainable ones. Among the latter hydrogen-derived fuels (the so-called electrofuels or e-fuels) are maybe the most interesting. This work addresses the effect of partial substitution of diesel fuel by hydrogen and hydrogen-carriers (ammonia and methane) on the autoignition process under low temperature conditions. Tests were carried out in a constant volume combustion chamber at different temperatures (535 600 and 650 ◦C) and pressures (11 16 and 21 bar). While the cool flames timing and intensity was only slightly affected by the low reactivity fuel energy content the main ignition was delayed this effect being much more noticeable for ammonia followed by hydrogen and finally methane. Kinetic simulations showed a clear competition for active radicals between both fuels (diesel and low reactivity fuel). The combustion duration also increased with the hydrogen or hydrogen-carrier content which greatly points to the need of modifications in the injection strategy of compression ignition engines operating under dual mode. A correlation was proposed for estimating the autoignition delay time for dual-fuel lean combustion at low temperature.

In this paper hydrogen coupled with fuel cells and lithium-ion batteries are considered as alternative energy storage methods. Their application on a stationary system (i.e. energy storage for a family house) and a mobile system (i.e. an unmanned aerial vehicle) will be investigated. The stationary systems designed for off-grid applications were sized for photovoltaic energy production in the area of Turin Italy to provide daily energy of 10.25 kWh. The mobile systems to be used for high crane inspection were sized to have a flying range of 120 min one being equipped with a Li-ion battery and the other with a proton-exchange membrane fuel cell. The systems were compared from an economical point of view and a life cycle assessment was performed to identify the main contributors to the environmental impact. From a commercial point of view the fuel cell and the electrolyzer being niche products result in being more expensive with respect to the Li-ion batteries. On the other hand the life cycle assessment (LCA) results show the lower burdens of both technologies.

In the present study Reynolds-Averaged Navier-Stokes simulations together with a novel flamelet generated manifold (FGM) hybrid combustion model incorporating preferential diffusion effects is utilised for the investigation of a hydrogen-blended diesel-hydrogen dual-fuel engine combustion process with high hydrogen energy share. The FGM hybrid combustion model was developed by coupling laminar flamelet databases obtained from diffusion flamelets and premixed flamelets. The model employed three control variables namely mixture fraction reaction progress variable and enthalpy. The preferential diffusion effects were included in the laminar flamelet calculations and in the diffusion terms in the transport equations of the control variables. The resulting model is then validated against an experimental diesel-hydrogen dual-fuel combustion engine. The results show that the FGM hybrid combustion model incorporating preferential diffusion effects in the flame chemistry and transport equations yields better predictions with good accuracy for the in-cylinder characteristics. The inclusion of preferential diffusion effects in the flame chemistry and transport equations was found to predict well several characteristics of the diesel-hydrogen dual-fuel combustion process: 1) ignition delay 2) start and end of combustion 3) faster flame propagation and quicker burning rate of hydrogen 4) high temperature combustion due to highly reactive nature of hydrogen radicals 5) peak values of the heat release rate due to high temperature combustion of the partially premixed pilot fuel spray with entrained hydrogen/air and then background hydrogen-air premixed mixture. The comparison between diesel-hydrogen dual-fuel combustion and diesel only combustion shows early start of combustion longer ignition delay time higher flame temperature and NOx emissions for dual-fuel combustion compared to diesel only combustion.

The use of hydrogen as energy carrier in a low emission microturbine could be an interesting option for renewable energy storage distributed generation and combined heat & power. However the hydrogen using in gas turbine is limited by the NOx emissions and the difficulty to operate safely. CFD simulations represent a powerful and mature tool to perform detailed 3-D investigation for the development of a prototype before carrying out an experimental analysis. This paper describes the CFD supported redesign of the Turbec T100 microturbine combustion chamber natural gas-fired to allow the operation on 100% hydrogen.

Hydrogen is considered one of the main gaseous fuels due to its ability to improve thermal performance in diesel engines. However its influence on the characteristics of lubricating oil is generally ignored. Thus in the present investigation an analysis of the effect on the physical and chemical properties of lubricating oil with mixtures of diesel fuel–hydrogen was carried out and the environmental impacts of this type of mixture were assessed. The development of the research was carried out using a diesel engine under four torque conditions (80 Nm 120 Nm 160 Nm and 200 Nm) and three hydrogen gas flow conditions (0.75 lpm 1.00 lpm and 1.25 lpm). From the results it was possible to demonstrate that the presence of hydrogen caused decreases of 3.50% 6.79% and 4.42% in the emissions of CO HC and smoke opacity respectively. However hydrogen further decreased the viscosity of the lubricating oil by 26%. Additionally hydrogen gas produced increases of 17.7% 29.27% 21.95% and 27.41% in metallic components such as Fe Cu Al and Cr respectively. In general hydrogen favors the contamination and oxidation of lubricating oil which implies a greater wear of the engine components. Due to the significantly negative impact of hydrogen on the lubrication system it should be considered due to its influence on the economic and environmental cost during the engine’s life cycle.

The presented article aims to design an educational test bench setup for smart grids and renewable energies with multiple features and techniques used in a microgrid. The test bench is designed for students laboratory engineers and researchers which enables electrical microgrid system studies and testing of new advanced control algorithms to optimize the energy efficiency. The idea behind this work is to design hybrid energy sources such as wind power solar photovoltaic power hydroelectric power hydrogen energy and different types of energy storage systems such as batteries pumped storage and flywheel integrating different electrical loads. The user can visualize the state of the components of each emulated scenario through an open-source software that interacts and communicates using OPC Unified Architecture protocol. The researchers can test and validate new solutions to manage the energy behavior in the grid using machine learning and optimization algorithms integrated in the software in form of blocks that can be modified and improved and then simulate the results. A model-based system of engineering is provided which describes the different requirements and case studies of the designed test bench respecting the open-source software and the frugal innovation features in which there is use of low-cost hardware and open-source software. The users obtain the opportunity to add new sources and new loads change software platforms and communicate with other simulators and equipment. The students can understand the different features of smart grids such as defect classification energy forecasting energy optimization and basics of production transmission and consumption.

In an era where the energy landscape is in constant transition energy leaders must pay attention to many different signals of change and distinguish key issues from the noise. The Issues Monitor identifies shifting patterns of connected issues which are shaping energy transitions.<br/>This report takes a focused look at the issues facing the energy transition in Europe using data collected by surveying over 40 leaders and shapers representing the European Transmission and Distributors Operators. This Issues Monitor outlines clear Action Priorities and Critical Uncertainties for different stakeholder groups mapping them out intuitively to promote a shared understanding of the issues. These maps also help identifiy regional variations understand differing areas of concern as well as follow the evolution of specific technology trends.<br/>Produced in partnership with ENTSO-E and E.DSO.

ISSUES MONITOR 2020: DECODING NEW SIGNALS OF CHANGE

The annual World Energy Issues Monitor provides unique insight into what energy policymakers CEOs and leading experts identify as Critical Uncertainties and Action Priorities. New this year the Issues Monitor also provides readers with the views of the individual customer detailing their perceptions of their role in the overall energy system. The Issues Monitor report includes a global issues map 58 country maps and six regional maps as well as perspectives from Future Energy Leaders (FEL) and energy innovators.

GLOBAL PERSPECTIVES

The 2020 global map incorporates all survey responses representing the views of over 3000 energy leaders from 104 countries. In this era of transition defined by decentralisation digitalisation and decarbonisation energy leaders must pay attention to many different signals of change and distinguish key issues from the noise. The Issues Monitor identifies shifting patterns of connected issues shaping energy transitions.

A NEW PULSE

The focus for the 2010s was about trying to automate and upgrade the energy system and set targets to move the energy transition forward. Digitalisation accelerated the transition of all sectors towards a more customer-centric environment. New policies and regulations were introduced to facilitate this transition and empower consumers. As a result the 2020s may very well be about realising those targets through a transition from activism to action.

TREND TRACKING: CCS

In comparing response from the Oil & Gas sector in 2015 with 2019 we found that almost half of respondents identified Carbon Capture & Storage (CCS) as a high impact issue in 2019 up from about a third in 2015. CCS is increasingly being viewed as an essential option for continued hydrocarbon use although governmental support is needed to enable scalability and cost effectiveness.

A DIFFERENCE IN OPINION: NUCLEAR

Opinions remain polarised but in many European countries nuclear power is increasingly recognised as a carbon-free energy source and potentially an integral part of the future energy mix. In December 2019 the European Commission set a target of net-zero carbon emissions by 2050. There is qualified support among energy leaders to include nuclear energy to help create a carbon neutral continent and enable a just energy transition.