Publications

Human activities have exacerbated global greenhouse effects resulting in extreme climate changes that have caused disasters and food and water shortages in recent years. Transport activities are the one of the main causes of global greenhouse gas (GHG) emissions. Therefore policy makers must develop some strategies to reduce GHG emissions. One of the Taiwan’s transportation policies intended to reduce CO2 emissions is to replace all traditional diesel fuel urban buses with alternative energy buses. This paper uses a case study of bus route NO. 2 in Tainan City and follows the international standard ISO/TS 14067 and PAS2050 to measure the carbon footprints of different energy buses. The purpose is to measure the environmental benefits of alternative energy buses. The results of the bus carbon footprints from high to low were LNG buses 63.14g CO2e/pkm; traditional diesel buses 54.6g CO2e/pkm; liquefied petroleum gas buses 47.4g CO2e/pkm; plug-in electric buses 37.82g CO2e/pkm and hydrogen fuel cell bus es 29.17g CO2e/pkm respectively. It was also found that the use of hydrogen fuel cell buses would potentially reduce CO2e emissions in Tainan City by 1244081 tons which at this time is only city bus No. 2. If all the Taiwan city buses were switched to hydrogen fuel cell buses this would potentially reduce CO2e by 227832.39 tons. The effect of the reduction in carbon emissions from the use of hydrogen fuel cells buses in all Taiwanese urban areas is the equivalent of planting 22.78 million trees. It is thus suggested that the government use hydrogen fuel cell buses as the future of the country’s major alternative energy buses since they are the most environmentally friendly alternative to reducing CO2 emissions.

On this episode of Everything About Hydrogen we chat with Andrew Cunningham Founder and Director at GeoPura. GeoPura is enabling the production transport and use of zero-emissions fuels with innovative and commercially viable technology to decarbonise the global economy. As the world transitions away from fossils fuels there is an increasing need for reliable clean electricity. If global power demand continues to grow as expected the electricity grid system will need support from renewable energy sources such as hydrogen and fuel cell power generator. GeoPura seeks to address exactly that kind of need.

The podcast can be found on their website

Island energy systems are becoming an important part of energy transformation due to the growing needs for the penetration of renewable energy. Among the possible systems a combination of different energy generation technologies is a viable option for local users as long as energy storage is implemented. The presented paper describes an energy-economic assessment of an island system with a photovoltaic field small wind turbine wood chip gasifier battery and hydrogen circuit with electrolyzer and fuel cell. The system is designed to satisfy the electrical energy demand of a tourist facility in two European localizations. The operation of the system is developed and dynamically simulated in the Transient System Simulation (TRNSYS) environment taking into account realistic user demand. The results show that in Gdansk Poland it is possible to satisfy 99% of user demand with renewable energy sources with excess energy equal to 31% while in Agkistro Greece a similar result is possible with 43% of excess energy. Despite the high initial costs it is possible to obtain Simple Pay Back periods of 12.5 and 22.5 years for Gdansk and Agkistro respectively. This result points out that under a high share of renewables in the energy demand of the user the profitability of the system is highly affected by the local cost of energy vectors. The achieved results show that the system is robust in providing energy to the users and that future development may lead to an operation based fully on renewables.

Hydrogen fuel in internal combustion engine gives a very big advantage to the transportation sector especially in solving the greenhouse emission problem. However there are only few research discovered the ability of argon as a working gas in hydrogen combustion in internal combustion engine. The high temperature rises from the argon compression tend to result in heat loss problem. This research aims to study the heat loss mechanism on wall surface condition in the combustion chamber. Experiments were conducted to study the effects of different heat flux sensor locations and the effect of ignition delay on heat flux. Local heat flux measurement was collected and images were observed using high speed shadowgraph images. The ignition delay that occurred near the combustion wall will result in larger heat loss throughout the combustion process. Higher ambient pressure results in a bigger amount of heat flux value. Other fundamental characteristics were obtained and discussed which may help in contributing the local heat loss data of an argon-circulated hydrogen engine in future engine operation.

With the constant increase in variable renewable energy production in electricity and district heating systems integration with the gas system is a way to provide flexibility to the overall energy system. In the sustainable transition towards a zero-emission energy system traditional natural gas can be substituted by renewable gasses derived from anaerobic digestion or thermal gasification and hydrogen. In this paper we present a methodology for modelling renewable gas options and limits on biomass resources across sectors in the energy optimisation model Balmorel. Different scenarios for socio-economic pathways to emission neutral electricity and district heating systems in Denmark Sweden Norway and Germany show that a renewable based energy system benefits from a certain percentage of gas as a supplement to other flexibility options like interconnectors. Especially upgraded biogas from anaerobic digestion serves as a substitute for natural gas in all scenarios. Allocating only 10% of available biomass to the electricity and district heating sector leads to full exploitation of the scarce biomass resource by boosting biogas and syngas with hydrogen. The need for renewable gasses is highest in Germany and least in Norway where hydro-power provides flexibility in terms of storable and dispatchable electricity production. The scenarios show that a required ‘‘late sprint" from fossils to achieve a zero-emission energy system in 2050 causes (1) significant higher accumulated emissions and (2) a system which strongly relies on fuels also in an emission free system instead of stronger integration of the electricity and district heating systems through electrification as well as stronger integration of the power systems across countries through interconnectors.

The crisscross progress of transportation and energy carries the migrating track of human society development and the evolution of civilization among which the decarbonization strategy is a key issue. Traffic carbon emissions account for 16.2% of total energy carbon emissions while road traffic carbon emissions account for 11.8% of total energy carbon emissions. Therefore road traffic is a vital battlefield in attaining the goal of decarbonization. Employing clean energy as an alternative fuel is of great significance to the transformation of the energy consumption structure in road transportation. Hydrogen and ammonia are renewable energy with the characteristics of being widely distributed and clean. Both exist naturally in nature and the products of complete combustion are substances (water and nitrogen) that do not pollute the atmosphere. Because it can promote agricultural production ammonia has a long history in human society. Both have the potential to replace traditional fossil fuel energy. An overview of the advantages of hydrogen and ammonia as well as their development in different countries such as the United States the European Union Japan and other major development regions is presented in this paper. Related research topics of hydrogen and ammonia’s production storage and transferring technology have also been analyzed and collated to stimulate the energy production chain for road transportation. The current cost of green hydrogen is between $2.70–$8.80 globally which is expected to approach $2–$6 by 2030. Furthermore the technical development of hydrogen and ammonia as a fuel for engines and fuel cells in road transportation is compared in detail and the tests practical applications and commercial popularization of these technologies are summarized respectively. Opportunities and challenges coexist in the era of the renewable energy. Based on the characteristics and development track of hydrogen and ammonia the joint development of these two types of energy is meant to be imperative. The collaborative development mode of hydrogen and ammonia together with the obstacles to their development of them are both compared and discussed. Finally referring to the efforts and experiences of different countries in promoting hydrogen and ammonia in road transportation corresponding constructive suggestions have been put forward for reference. At the end of the paper a framework diagram of hydrogen and ammonia industry chains is provided and the mutual promotion development relationship of the two energy sources is systematically summarized.

As an important component of hydrogen fuel cell vehicles the air compressor with an air foil bearing rotates at tens of thousands of revolutions per minute. The heat generation concentration problem caused by the high-speed motor loss seriously affects the safe and normal operation of the motor so it is very important to clarify the loss distribution of the high-speed motor and adopt a targeted loss reduction design for air compressor heat dissipation. In this paper for an air compressor with a foil bearing with a rated speed of 80000 rpm an empirical formula and a three-dimensional transient magnetic field finite element model are used to model and calculate the air friction loss stator core loss winding loss and permanent magnet eddy current loss. The accuracy of the analytical calculation method is verified by torque test experiments under different revolutions and the average simulation accuracy can reach 91.1%. Then the distribution of the air friction loss stator core loss winding loss and eddy current loss of the air compressor motor at different revolutions is obtained by using this method. The results show that the proposed method can effectively calculate the motor rotor loss of a high-speed air compressor with air foil bearing. Although the motor efficiency increases with the increase in motor speed the absolute value of loss also increases with the increase in motor speed. Stator core loss and air friction loss are the main sources of loss accounting for 55.64% and 29% of the total motor loss respectively. The electromagnetic loss of winding the eddy current and other alloys account for a relatively small proportion which is 15% in total. The conclusions obtained in this paper can effectively guide calculations of motor loss the motor heat dissipation design of a high-speed air compressor with an air foil bearing.

This paper discusses the potential for green-hydrogen production in a run-of-river 9 hydropower plant. This particular hydropower plant has no significant water accumulation but 10 there is the potential for limited hydrogen production due to a mismatch between the daily 11 predefined electricity production (known as the timetable) and the actual water inflows. The 12 timetable for the hydropower plant is prepared by the operator of the electro-energetic system 13 based on a model of the available production capacities forecasted consumption water 14 accumulation state of the river flows weather forecasts and the system operator’s strategy. The 15 uncertainty in the model’s input parameters is reflected in the output timetable for the 16 hydropower plant and for this reason a small reserve of water for potential exploitation is 17 envisaged. By using real data for the timetable and the water inflow we estimate the excess 18 hydropower that can be used for hydrogen cogeneration. Since the primary task of the 19 hydropower plant is to produce electricity according to the timetable the production of 20 hydrogen is only possible to a limited extent. Therefore we present a control algorithm that 21 regulates the amount of hydrogen production while considering the predefined timetable and 22 the real water accumulation. The second part of the paper deals with the economic viability of 23 hydrogen cogeneration in the case-study run-of-river hydropower plant and discusses the 24 possibility of using it for local public transport.

As a fuel for power generation high-pressure hydrogen gas is widely used for transportation and its efficient storage promotes the development of fuel cell vehicles (FCVs). However as the filling process takes such a short time the maximum temperature in the storage tank usually undergoes a rapid increase which has become a thorny problem and poses great technical challenges to the steady operation of hydrogen FCVs. For security reasons SAE J2601/ISO 15869 regulates a maximum temperature limit of 85 ◦C in the specifications for refillable hydrogen tanks. In this paper a two-dimensional axisymmetric and a three-dimensional numerical model for fast charging of Type III 35 MPa and 70 MPa hydrogen vehicle cylinders are proposed in order to effectively evaluate the temperature rise within vehicle tanks. A modified standard k-ε turbulence model is utilized to simulate hydrogen gas charging. The equation of state for hydrogen gas is adopted with the thermodynamic properties taken from the National Institute of Standards and Technology (NIST) database taking into account the impact of hydrogen gas’ compressibility. To validate the numerical model three groups of hydrogen rapid refueling experimental data are chosen. After a detailed comparison it is found that the simulated results calculated by the developed numerical model are in good agreement with the experimental results with average temperature differences at the end time of 2.56 K 4.08 K and 4.3 K. The present study provides a foundation for in-depth investigations on the structural mechanics analysis of hydrogen gas vessels during fast refueling and may supply some technical guidance on the design of charging experiments.

This opinion piece describes how the optimal integration of hydrogen-fuel-cell with battery in a heavy highly-utilised vehicle can extend vehicle range while cutting refuelling time and reducing cost compared to a pure battery electric vehicle.