Netherlands

This paper evaluates the potential impacts of introducing low-carbon intensity hydrogen technologies in two oil refineries with different complexity levels emphasizing the role of hydrogen production in reducing CO2 emissions. The novelty of this work lies in three key aspects: Comprehensive system analysis of refinery complexity using real site data integration of low-carbon Hydrogen technologies long-term and short-term strategies. Two Colombian refineries serve as case studies with technological solutions adapted to their complexity levels. The methodology involves evaluating different options for hydrogen production accounting for improvement in technological efficiency over time.<br/>The refinery systems were evaluated in a cost-optimization model built in Linny-r. Three different scenarios were considered Business-As-Usual (BAU) high and low-ambitions decarbonization scenarios focusing on the time horizons of 2030 and 2050.<br/>When comparing the two case studies the preferred decarbonization strategy for both facilities involves the substitution of SMR technology with water electrolyzers powered by renewable electricity. Post-2030 biomass-based hydrogen technology is still a costly alternative; however to achieve CO2 neutrality negative emissions storage of biogenic CO2 emerges as an achievable alternative.<br/>Our results indicate the achievability of CO2 reduction objectives in both refineries. Our results show that achieving long-term CO2 neutrality requires both refineries to increase renewable electricity production by 5 to 6 times for powering water electrolyzers steam production by 2 to 2.5 times for CO2 capture and supply of dry biomass by 2.6 to 4.5 kt/d.<br/>The two most significant factors influencing the refining net margin in the decarbonization scenarios are primarily the CO2 and the renewable electricity prices. The short-term horizon emerges as the pivotal period particularly within the high-ambition decarbonization scenarios. In this context the medium complexity refinery demonstrates economic viability until a CO2 price of 140 €/t CO2 while the high complexity refinery endures up to 205 €/t CO2.<br/>The high complexity refinery is better prepared to face the challenges of decarbonization and the impacts generated on the refining margin. Compared to the BAU scenario the high complexity refinery shows a negative impact on the net margin that corresponds to a 40% and 5% reduction in the short and long term respectively. Meanwhile for the medium complexity refinery the impact on net margin amounts to a 52% reduction in the short term and a 27% improvement in the long term.<br/>Furthermore our research highlights the significant potential for reducing CO2 emissions by fully eliminating the use of refinery gas as fuel providing alternative applications for it beyond combustion.

The number of species and elementary reactions needed for describing the oxidation of fuels increases with the size of the molecule and in turn the complexity of detailed mechanisms. Although the kinetics for conventional fuels (H2 CH4 C3H8...) are somewhat well-established chemical integration in detonation applications remains a major challenge. Significant efforts have been made to develop reduction techniques that aim to keep the predictive capabilities of detailed mechanisms intact while minimizing the number of species and reactions required. However as their starting point of development is based on homogeneous reactors or ZND profiles reduced mechanisms comprising a few species and reactions are not predictive. The methodology presented here relies on defining virtual chemical species such that the thermodynamic equilibrium of the ZND structure is properly recovered thereby circumventing the need to account for minor intermediate species. A classical asymptotic expression relating the ignition delay time with the reaction rate constant is then used to fit the Arrhenius coefficients targeting computations carried out with detailed kinetics. The methodology was extended to develop a three-step mechanism in which the Arrhenius coefficients were optimized to accurately reproduce the one-dimensional laminar ZND structure and the D−κ curves for slightly-curved quasi-steady detonation waves. Two-dimensional simulations performed with the three-step mechanism successfully reproduce the spectrum of length scales present in soot foils computed with detailed kinetics (i.e. cell regularity and size). Results attest for the robustness of the proposed methodology/approximation and its flexibility to be adapted to different configurations.

Hydrogen economy is spreading across the maritime sector in response to increasingly stringent regulations for shipping emissions. The challenging on-board hydrogen logistics are often mitigated with hydrogen carriers such as methanol. Research on methanol reforming to hydrogen for fuel cell feed is conducted mostly in steady state overlooking dynamic reactor operation and its effects on the power production system. Forced reactor operations induce fluctuations of CO content in the reformate potentially harmful to the PEM fuel cell and drops in methanol conversion causing inefficient operation. In present research simulations with a physical 2D unsteady model of a packed bed methanol steam reforming reactor resulted in methanol conversion drop durations of up to a minute. Additionally temporary increases of CO content up to 112% were observed. Throughput ramp ups most notably impact the conversion while ramp downs negatively affect selectivity. The investigation on reactor geometry concludes that larger tube diameters increase transient time and CO spikes while they decrease with reactor length. Amplified unsteady effects are also observed with larger changes in input process variables. The results imply that heat transfer rate to the reactor are most often the detrimental factor for transient effects and durations in practice. Following this work inclusion of realistic heating methods is recommended instead of uniform tube temperatures used in present simulations. Heating system characteristics are necessary for realistic evaluation of the methanol reformer constraint on fuel cell feed demand in fully integrated systems.

This research aims to determine the position and the breakthrough trajectory of sustainable energy technologies. Fine-grained insights into these breakthrough positions and trajectories are limited. This research seeks to fill this gap by analyzing sustainable energy technologies’ breakthrough positions and trajectories in terms of development application and upscaling. To this end the breakthrough positions and trajectories of seven sustainable energy technologies i.e. hydrogen from seawater electrolysis hydrogen airplanes inland floating photovoltaics redox flow batteries hydrogen energy for grid balancing hydrogen fuel cell electric vehicles and smart sustainable energy houses are analyzed. This is guided by an extensively researched and literature-based model that visualizes and describes these technologies’ experimentation and demonstration stages. This research identifies where these technologies are located in their breakthrough trajectory in terms of the development phase (prototyping production process and organization and niche market creation and sales) experiment and demonstration stage (technical organizational and market) the form of collaboration (public–private private–public and private) physical location (university and company laboratories production sites and marketplaces) and scale-up type (demonstrative and first-order and second-order transformative). For scientists this research offers the opportunity to further refine the features of sustainable energy technologies’ developmental positions and trajectories at a detailed level. For practitioners it provides insights that help to determine investments in various sustainable energy technologies.

Hydrogen use is increasing in transportation including within the railway sector. In collaboration with a governmental institution in the Netherlands we study how to design an efficient hydrogen fueling infrastructure for a railway system. The problem involves selecting yards in a network for hydrogen fueling assigning trains to these yards locating hydrogen storage and fueling stations and connecting them via pipelines. This key planning phase must avoid oversizing costly fueling infrastructure while accounting for track availability at yards and costs due to fueling operations. We formulate this novel problem which has the structure of a nested facility location problem as a mixed-integer linear program to minimize total annualized investment and operational costs. Due to the complexity of real-sized instances we propose a matheuristic that estimates the infrastructural costs for each yard and train assignment by combining a constructive algorithm with a set covering model. It then solves a single-stage facility location problem to select yards and assign trains followed by a yard-level improvement phase. Numerical experiments on a real Dutch case show that our approach delivers high-quality solutions quickly and offer insights into the optimal infrastructure design depending on the discretization of yard areas number of trains and other parameters.

Energy production and consumption are major contributors to greenhouse gas (GHG) emissions exacerbating one of the greatest challenges faced by modern societies: climate change. Thus societies must switch to more sustainable energy sources. Green hydrogen has emerged as a promising alternative energy carrier facilitating storage and utilization across various industries. However amidst different production processes solely sustainable electrolysis stands out as an environmentally benign production method. Hydrogen producers must prove provenance and sustainable production to regulatory bodies and hydrogen buyers to comply with the regulations for sustainable development. Blockchain provides a viable solution encompassing trustworthy and secure information sharing between untrusted partners. In this article we employ a design science research approach to develop a blockchain-based certification system (BLC-CS) for green hydrogen. Through collaboration with experts to gather requirements and conduct evaluations we design an artifact that streamlines the certification process for producers regulators and consumers. Our proposed solution facilitates information gathering verification and reporting contributing to the advancement of sustainable energy practices. We provide a comprehensive discussion of the BLC-CS’s feasibility for green hydrogen certification including technical extensions recommendations for practitioners and directions for future research.

Advanced zero-gap alkaline electrolyzers can be operated at a significantly higher current density than traditional alkaline electrolyzers. We have investigated how their performance is influenced by diaphragm thickness temperature and pressure. For this a semiempirical current-voltage model has been developed based on experimental data of a 20 Nm3 /h electrolyzer. The model was extrapolated to thinner diaphragm thicknesses and higher temperatures showing that a nominal current density of 1.8 A cm2 is possible with a 0.1 mm diaphragm at 100 C. However these operating parameters also lead to increased gas crossover which limits the ability to operate at low loads. A gas crossover model has been developed which shows that crossover is mainly driven by diffusive transport of hydrogen caused by a high local supersaturation at the diaphragm surface. To enable a low minimum load of 10% the operating pressure should be kept below 8 bara.

In recent years the intensification of human activities has led to an increase in waste production and energy demand. The treatment of pollutants contained in wastewater coupled to energy recovery is an attractive solution to simultaneously reduce environmental pollution and provide alternative energy sources. Hydrogen represents a clean energy carrier for the transition to a decarbonized society. Hydrogen can be generated by photosynthetic water splitting where oxygen and hydrogen are produced and the process is driven by the light energy absorbed by the photocatalyst. Alternatively hydrogen may be generated from hydrogenated pollutants in water through photocatalysis and the overall reaction is thermodynamically more favourable than water splitting for hydrogen. This review is focused on recent developments in research surrounding photocatalytic and photoelectrochemical hydrogen production from pollutants that may be found in wastewater. The fundamentals of photocatalysis and photoelectrochemical cells are discussed along with materials and efficiency determination. Then the review focuses on hydrogen production linked to the oxidation of compounds found in wastewater. Some research has investigated hydrogen production from wastewater mixtures such as olive mill wastewater juice production wastewater and waste activated sludge. This is an exciting area for research in photocatalysis and semiconductor photoelectrochemistry with real potential for scale up in niche applications.

Decarbonizing the steel industry will require a shift towards renewable energy. However costs and emissions associated with the long-distance transport of renewable energy carriers may incentivize the relocation of steel production closer to renewable energy sources. This “green relocation” would affect regional economic structures and global trade patterns. Nevertheless the macroeconomic and environmental impacts of alternative industry location options remain underexplored. This study compares the impacts on value-added prices and emissions under two options for decarbonizing the Dutch steel industry: importing green hydrogen from Brazil to produce green steel in the Netherlands versus relocating production to Brazil and transporting green steel to the Netherlands. Impacts are analyzed by combining a price and a quantity model within an environmentally extended multiregional input-output (EE-MRIO) framework. Results suggest that the relocation option brings the greatest synergies between climate and economic goals at the global level as it leads to lower production costs smaller price effects and greater emissions reductions. However relocation also results in stronger distributive impacts across global regions. Higher carbon prices would be insufficient to counteract relocation incentives. This calls for policymakers in industrialized countries to systematically consider the possibility of green relocation when designing decarbonization and industrial competitiveness strategies.

Achieving net-zero emissions requires major changes across a nation’s economy energy and land systems particularly due to sectors where emissions are difficult to eliminate. Here we adapt two global scenarios from the International Energy Agency—the net-zero emissions by 2050 and the Stated Policies Scenario—using an integrated numerical economic-energy model tailored to Australia. We explore how emissions may evolve by sector and identify key technologies for decarbonisation. Our results show that a rapid shift to near-zero emissions electricity is central to reducing costs and enabling wider emissions reductions. From 2030 onwards carbon removal through land management and engineered solutions such as direct air capture and bioenergy with carbon capture and storage becomes critical. Australia is also well-positioned to become a global supplier of clean energy such as hydrogen made using renewable electricity helping reduce emissions beyond its borders.