Publications

To improve the renewable energy consumption capacity of integrated energy system (IES) and reduce the carbon emission level of the system a low-carbon economic dispatch model of IES with coupled power-to-gas (P2G) and hydrogen-doped gas units (HGT) under the stepped carbon trading mechanism is proposed. On the premise of wind power output uncertainty the operating characteristics of the coupled electricity-to-gas equipment in the system are used to improve the wind abandonment problem of IES and increase its renewable energy consumption capacity; HGT is introduced to replace the traditional combustion engine for energy supply and on the basis of refined P2G a part of the volume fraction of hydrogen obtained from the production is extracted and mixed with methane to form a gas mixture for HGT combustion so as to improve the low-carbon economy of the system. The ladder type carbon trading mechanism is introduced into IES to guide the system to control carbon emission behavior and reduce the carbon emission level of IES. Based on this an optimal dispatching strategy is constructed with the economic goal of minimizing the sum of system operation cost wind abandonment cost carbon trading cost and energy purchase cost. After linearization of the established model and comparison analysis by setting different scenarios the wind power utilization rate of the proposed model is increased by 24.5% and the wind abandonment cost and CO2 emission are reduced by 86.3% and 10.5% respectively compared with the traditional IES system which achieves the improvement of renewable energy consumption level and low carbon economy.

Hydrogen has received much attention in the development of direct reduction of iron ores because hydrogen metallurgy is one of the effective methods to reduce CO2 emission in the iron and steel industry. In this study the kinetic mechanism of reduction of hematite particles was studied in a hydrogen atmosphere. The phases and morphological transformation of hematite during the reduction were characterized using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. It was found that porous magnetite was formed and the particles were degraded during the reduction. Finally sintering of the reduced iron and wüstite retarded the reductive progress. The average activation energy was extracted to be 86.1 kJ/mol and 79.1 kJ/mol according to Flynn-Wall-Ozawa (FWO) and Starink methods respectively. The reaction fraction dependent values of activation energy were suggested to be the result of multi-stage reactions during the reduction process. Furthermore the variation of activation energy value was smoothed after heat treatment of hematite particles.

Hydrogen energy systems (HES) are increasingly recognized as pivotal in cutting global carbon dioxide (CO2) emissions especially in transportation power generation and industrial sectors. This paper offers a comprehensive review of HES emphasizing their diverse applications and economic viability. By 2030 hydrogen energy is expected to revolutionize various sectors significantly impacting CO2 abatement and energy demand. In electricity and power generation hydrogen could reduce CO2 emissions by 50–100 million tons annually requiring 10–20 million tons of hydrogen and an investment of $50–100 billion underscoring its role in grid stabilization. Additionally in the heating sector hydrogen could facilitate a CO2 abatement of 30–50 million tons. We examine the levelized cost of hydrogen (LCOH) production influenced by factors like production methods efficiency and infrastructure. While steam methane reforming is cost-effective it poses a larger environmental impact compared to electrolysis. The global life-cycle cost of hydrogen production decreases as production scales up with current costs ranging from $1–3 per kg for fossil-based sources to $3.4–7.5 per kg for electrolysis using low-emission electricity. These costs are projected to decrease especially for electrolytic hydrogen in regions with abundant solar energy. However despite the technical feasibility of decarbonization high production costs still pose challenges. A systematic and effective transition to a hydrogen economy requires comprehensive policy and financial support mechanisms including incentives subsidies tax measures and funding for research and development of pilot projects. Additionally the paper discusses hydrogen's role in advanced storage technologies such as hydrides and Japan's ENE-FARM solution for residential energy emphasizing the need for strategic investments across the hydrogen value chain to enhance HES competitiveness reduce LCOH and advance the learning rates of hydrogen production technologies.

The automotive industry is undergoing a profound transformation driven by the need for sustainable and environmentally friendly transportation solutions [1]. In this context fuel cell technology has emerged as a promising alternative offering clean efficient and high-performance power sources for vehicles [2]. Fuel cell vehicles are electric vehicles that use fuel cell systems as a single power source or as a hybrid power source in combination with rechargeable energy storage systems. A typical fuel cell system for electric vehicle is exhibited in Figure 1 which provides a comprehensive demonstration of this kind of complex system. Hydrogen energy is a crucial field in the new energy revolution and will become a key pillar in building a green efficient and secure new energy system. As a critical field for hydrogen utilization fuel cell vehicles will play an important role in the transformation and development of the automotive industry. The development of fuel cell vehicles offers numerous advantages such as strong power outputs safety reliability and economic energy savings [3]. However improvements must urgently be made in existing technologies such as fuel cell stacks (including proton exchange membranes catalysts gas diffusion layers and bipolar plates) compressors and onboard hydrogen storage systems [4]. The advantages and current technological status are analyzed here.

Offshore wind power stands out as a promising renewable energy source offering substantial potential for achieving low carbon emissions and enhancing energy security. Despite its potential the expansion of offshore wind power faces considerable constraints in offshore power transmission. Hydrogen production derived from offshore wind power emerges as an efficient solution to overcome these limitations and effectively transport energy. This study systematically devises diverse hydrogen energy supply chains tailored to the demands of the transportation and chemical industries meticulously assessing the levelized cost of hydrogen (LCOH). Our findings reveal that the most cost-efficient means of transporting hydrogen to the mainland is through pipelines particularly when the baseline distance is 50 km and the baseline electricity price is 0.05 USD/kWh. Notably delivering hydrogen directly to the port via pipelines for chemical industries proves considerably more economical than distributing it to hydrogen refueling stations with a minimal cost of 3.6 USD/kg. Additionally we assessed the levelized cost of hydrogen (LCOH) for supply chains that transmit electricity to ports via submarine cables before hydrogen production and subsequent distribution to chemical plants. In comparison to offshore hydrogen production routes these routes exhibit higher costs and reduced competitiveness. Finally a sensitivity analysis was undertaken to scrutinize the impact of delivery distance and electricity prices on LCOH. The outcomes underscore the acute sensitivity of LCOH to power prices highlighting the potential for substantial reductions in hydrogen prices through concerted efforts to lower electricity costs.

In the pathway towards decarbonization hydrogen can provide valid support in different sectors such as transportation iron and steel industries and domestic heating concurrently reducing air pollution. Thanks to its versatility hydrogen can be produced in different ways among which steam reforming of natural gas is still the most commonly used method. Today less than 0.7% of global hydrogen production can be considered low-carbon-emission. Among the various solutions under investigation for low-carbon hydrogen production membrane reactor technology has the potential especially at a small scale to efficiently convert biogas into green hydrogen leading to a substantial process intensification. Fluidized bed membrane reactors for autothermal reforming of biogas have reached industrial maturity. Reliable modelling support is thus necessary to develop their full potential. In this work a mathematical model of the reactor is used to provide guidelines for their design and operations in off-design conditions. The analysis shows the influence of temperature pressures catalyst and steam amounts and inlet temperature. Moreover the influence of different membrane lengths numbers and pitches is investigated. From the results guidelines are provided to properly design the geometry to obtain a set recovery factor value and hydrogen production. For a given reactor geometry and fluidization velocity operating the reactor at 12 bar and the permeate-side pressure of 0.1 bar while increasing reactor temperature from 450 to 500 °C leads to an increase of 33% in hydrogen production and about 40% in HRF. At a reactor temperature of 500 °C going from 8 to 20 bar inside the reactor doubled hydrogen production with a loss in recovery factor of about 16%. With the reactor at 12 bar a vacuum pressure of 0.5 bar reduces hydrogen production by 43% and HRF by 45%. With the given catalyst it is sufficient to have only 20% of solids filled into the reactor being catalytic particles. With the fixed operating conditions it is worth mentioning that by adding membranes and maintaining the same spacing it is possible to increase hydrogen production proportionally to the membrane area maintaining the same HRF.

The supply storage and (international) transport of green hydrogen (H2) are essential for the decarbonization of the energy sector. The goal of this study was to assess the final cost-price and carbon footprint of imported green H2 in the market via maritime shipping of liquid organic hydrogen carriers (LOHCs) including dibenzyl toluene-perhydro-dibenzyltoluene (DBTPDBT) and toluene-methylcyclohexane (TOL-MCH) systems. The study focused on logistic steps in intra-European supply chains in different scenarios of future production in Portugal and demand in the Netherlands and carbon tariffs between 2030 and 2050. The case study is based on a formally accepted agreement between Portugal and the Netherlands within the Strategic Forum on Important Projects of Common European Interest (IPCEI). Under the following assumptions the results show that LOHCs are a viable technical-economic solution with logistics costs from 2030 to 2050 varying between 0.30-0.37 €/kg-H2 for DBT-PDBT and 0.28-0.34 €/kg-H2 for TOL-MCH. The associated CO2 emissions of these international H2 supply chains are between 0.46 and 2.46 kg-CO2/GJ (LHV) and 0.55-2.95 kg-CO2/GJ (LHV) for DBT-PDBT and TOL-MCH respectively.

Green hydrogen is gaining increasing attention as a key component of the global energy transition towards a more sustainable industry. Chile with its vast renewable energy potential is well positioned to become a major producer and exporter of green hydrogen. In this context this paper explores the prospects for green hydrogen production and use in Chile. The perspectives presented in this study are primarily based on a compilation of government reports and data from the scientific literature which primarily offer a theoretical perspective on the efficiency and cost of hydrogen production. To address the need for experimental data an ongoing experimental project was initiated in March 2023. This project aims to assess the efficiency of hydrogen production and consumption in the Atacama Desert through the deployment of a mobile on-site laboratory for hydrogen generation. The facility is mainly composed by solar panels electrolyzers fuel cells and a battery bank and it moves through the Atacama Desert in Chile at different altitudes from the sea level to measure the efficiency of hydrogen generation through the energy approach. The challenges and opportunities in Chile for developing a robust green hydrogen economy are also analyzed. According to the results Chile has remarkable renewable energy resources particularly in solar and wind power that could be harnessed to produce green hydrogen. Chile has also established a supportive policy framework that promotes the development of renewable energy and the adoption of green hydrogen technologies. However there are challenges that need to be addressed such as the high capital costs of green hydrogen production and the need for supportive infrastructure. Despite these challenges we argue that Chile has the potential to become a leading producer and exporter of green hydrogen or derivatives such as ammonia or methanol. The country’s strategic location political stability and strong commitment to renewable energy provide a favorable environment for the development of a green hydrogen industry. The growing demand for clean energy and the increasing interest in decarbonization present significant opportunities for Chile to capitalize on its renewable energy resources and become a major player in the global green hydrogen market.

Efficiently predicting and understanding refuelling patterns in the context of HFVs is paramount for optimising fuelling processes infrastructure planning and facilitating vehicle operation. This study evaluates several supervised machine learning methodologies for predicting the refuelling behaviour of HFVs. The LightGBM model emerged as the most effective predictive model due to its ability to handle time series and seasonal data. The selected model integrates various input variables encompassing refuelling metrics day of the week and weather conditions (e.g. temperature precipitation) to capture intricate patterns and relationships within the data set. Empirical testing and validation against real-world refuelling data underscore the efficacy of the LightGBM model demonstrating a minimal deviation from actual data given limited data and thereby showcasing its potential to offer valuable insights to fuelling station operators vehicle manufacturers and policymakers. Overall this study highlights the potential of sustainable predictive modelling for optimising fuelling processes infrastructure planning and facilitating vehicle operation in the context of HFVs.

Hydrogen gas can provide baseload energy as society decarbonizes through the energy transition. Underground Hydrogen Storage (UHS) will be secure convenient and scalable to accommodate excess hydrogen production or compensate temporary shortfalls in energy supply. Hydrogen is a gas under all viable subsurface conditions so is invasive mobile and low-density. Methane and CO2 are also stored underground but storage parameters differ for each affecting the balance of geological storage risks. UHS in Australia is most likely to utilise conventional sedimentary reservoir rocks bound by conventional trapping closures. Hydrogen energy density will affect the competitiveness of UHS against purpose-built surface storage or solution-mined salt cavities. This study presents an overview of key considerations when screening for UHS opportunities and evaluates them for five Australian sedimentary basins. A threshold storage depth mapped across them reveals that the most prospective UHS basins will have to function as integrated energy fluid resource systems.