Net Transition Research Articles

A Novel Method for General Hierarchical System Modeling via Colored Petri Nets Based on Transition Extractions from Real Datasets

The Colored Petri net (CPN) has evolved into a complete modeling language, which is based on the object-oriented paradigm. Although this language is quite complete and can be used to accurately model a wide variety of systems, it seems that there is a lack of certain modeling rules, which can be used to generate models based on real datasets. This paper is a first attempt to incorporate sequences of real system events and translate them into sequences of Petri net transitions. Then, well-defined modeling rules control the model generation based on these transitions. The specific entities that take part in each of the real system events, as well as their attributes are also considered. The models produced using real data are structured because, in the majority of real systems, each incurring event usually affects a part of the system. Then, this effect is propagated to the entire system. Therefore, it is much easier to divide the entire model into distinct parts when real data are used and then interconnect these parts to build an entire model. This is a very important aspect when modeling very large systems. To test our approach, we used the real data from a courier company to generate its model. Our simulation results have shown that we managed to obtain quite accurate results through the model produced by the actual data.

Decarbonizing the International Shipping and Aviation Sectors

The Paris Agreement requires a drastic reduction of global carbon emissions towards the net zero transition by mid-century, based on the large-scale transformation of the global energy system and major emitting sectors. Aviation and shipping emissions are not on a trajectory consistent with Paris goals, driven by rapid activity growth and the lack of commercial mitigation options, given the challenges for electrification of these sectors. Large-scale models used for mitigation analysis commonly do not capture the specificities and emission reduction options of international shipping and aviation, while bottom-up sectoral models do not represent their interlinkages with the entire system. Here, I use the global energy system model PROMETHEUS, enhanced with a detailed representation of the shipping and aviation sector, to explore transformation pathways for these sectors and their emission, activity, and energy mix impacts. The most promising alternative towards decarbonizing these sectors is the large-scale deployment of low-carbon fuels, including biofuels and synthetic clean fuels, accompanied by energy efficiency improvements. The analysis shows that ambitious climate policy would reduce the trade of fossil fuels and lower the activity and the mitigation effort of international shipping, indicating synergies between national climate action and international transport.

Feasible operation region of an electricity distribution network

In the course of net zero carbon transition, electricity distribution networks are faced with great challenges brought by increasing total and peak demand due to the electrification of transport and heat, as well as the significant uncertainties from renewable power generation and customer behaviors (such as electric vehicle travelling behaviors). Therefore, distribution network operators (DNOs) need effective tools to assess the capability of distribution networks in integrating generation and demand to conduct active management and efficient expansion of networks. However, conventional scenario-based assessment methods only provide conservative and limited information on the network capability, also with exponentially increased computational burden. By contrast, another stream of methods with different philosophy, named as operation region-based methods, describe the overall picture of the network capability analytically with little computational power needed. However, the existing linearized analytical regions, which are mainly applied to electricity transmission networks, cannot describe the capability of distribution networks accurately enough. To solve these problems, a novel feasible operation region (FOR) method with quadratic analytical expressions was proposed to characterize the range of the operating states of distribution networks, where the thermal and voltage constraints will not be violated. The FOR is a geometry in a high-dimensional space, and thus a high-dimensional error analysis approach was further developed for validating the proposed method. The boundary errors are described by multiple distance functions and operational indices, and the conservativeness of the analytical boundaries are quantified. An 11 kV radial distribution network from the United Kingdom Generic Distribution System (UKGDS) was used for the case study. The simulation results show that the quadratic analytical boundaries well approximated the real boundaries of FOR. The maximum errors for thermal and voltage boundaries would maximally cause an overcurrent up to 116 % and an undervoltage down to 0.96p.u., which are able to satisfy the requirements of engineering practice. Compared to the existing linear approximation (termed as hyperplane expressions) of FOR boundaries, the proposed quadratic expressions were proved to have higher accuracy.

Safety investigation of hydrogen energy storage systems using quantitative risk assessment

Hydrogen energy storage systems are expected to play a key role in supporting the net zero energy transition. Although the storage and utilization of hydrogen poses critical risks, current hydrogen energy storage system designs are primarily driven by cost considerations to achieve economic benefits without safety considerations. This paper aims to study the safety of hydrogen storage systems by conducting a quantitative risk assessment to investigate the effect of hydrogen storage systems design parameters such as storage size, mass flow rate, storage pressure and storage temperature. To this end, the quantitative risk assessment procedure, which includes data collection and hazard identification, frequency analysis, consequence analysis and risk analysis, was carried out for the hydrogen storage system presented in a previous study [1]. In the consequence analysis, the Millers model and TNO multi-energy were used to model the jet fire and explosion hazards, respectively. The results show that the storage capacity and pressure have the greatest influence on the hydrogen storage system risk assessment. More significantly, the design parameters may affect the acceptance criteria based on the gaseous hydrogen standard. In certain cases of large storage volume or high storage pressure, risk mitigation measures must be implemented since the risk of the hydrogen storage system is unacceptable in accordance with ISO 19880-1. The study highlights the significance of risk analysis conduction and the importance of considering costs associated with risk mitigation in the design of hydrogen storage system.

Community wealth building in an age of just transitions: Exploring civil society approaches to net zero and future research synergies

Community Wealth Building (CWB) is a burgeoning international policy agenda for local economic development that seeks to enhance democratic ownership, retain the benefits of local economic activity and empower place-based economies and workers. Parallel to this, in the context of net zero transitions, there has been increasing interest in approaches to enhancing civil society and community ownership over local energy provision. However, in academic and practitioner debates, there has been very little interaction between these two strands of thinking and action on the need for radical change in current energy provision, particularly as part of a wider transformative change away from dominant neoliberal economic thinking, policies and structures.In this Perspective, we explore the various ways in which synergies exist between CWB and energy transitions by considering two civil society approaches to transitions; namely, the Thousand Flowers transition pathway and research in Grassroots Innovations. We examine how community energy could be strengthened through CWB, by showing how the ideas within these two approaches respond to the five core principles of CWB. Promising future directions for research and practice are identified, including linking up CWB and just transitions strategies, a renewed focus on local financial innovation and the growing role of anchor institutions in supporting net zero transitions, particularly where CWB supports economic democracy transformations in new net zero economies.

Bet on innovation, not Environmental, Social and Governance metrics, to lead the Net Zero transition

AbstractThe conventional Net Zero perspective with its emphasis on Environmental, Social and Governance (ESG) metrics represents linear cause‐and‐effect thinking. That is, implementation of the metrics will then change company behaviour with the eventual effect of a successful Net Zero transition. Different perspectives are presented, rooted in systems thinking. Numerous company examples explain why innovation, not ESG metrics, will be the prime mover in achieving Net Zero. The crux of the argument for systems thinking is that a company like Honeywell, currently given an ‘F’ ESG score, is delivering stellar innovations that will enable its customers to significantly reduce their greenhouse gas emissions. As to behaviour, boards of directors should demand new information from management with particular attention to returns on capital versus the cost of capital under scenarios that include a price (tax) on carbon. The integration of corporate finance principles with systems thinking will improve decision‐making and facilitate an efficient Net Zero transition.

Analytical Decomposition of Transition Flux to Cycle Durations via Integration of Transition Times

Rigorous methods of decomposing kinetic networks to cycles are available, but the solutions usually contain entangled transition rates, which are difficult to analyze. This study proposes a new method of decomposing net transition flux to cycle durations, and the duration of each cycle is an integration of the transition times along the cycle. The method provides a series of neat dependences from the basic kinetic variables to the final flux, which support direct analysis based on the formulas. An assisting transformation diagram from symmetric conductivity to asymmetric conductivity is provided, which largely simplifies the application of the method. The method is likely a useful analytical tool for many studies relevant to kinetics and networks. Applications of the method shall provide new kinetic and thermodynamic information for the studied system.

Petri net transition times as training features for multiclass models to support the detection of neurodegenerative diseases

This paper proposes the transition times of Petri net models of human gait as training features for multiclass random forests (RFs) and classification trees (CTs). These models are designed to support screening for neurodegenerative diseases. The proposed Petri net describes gait in terms of nine cyclic phases and the timing of the nine events that mark the transition between phases. Since the transition times between strides vary, each is represented as a random variable characterized by its mean and standard deviation. These transition times are calculated using the PhysioNet database of vertical ground reaction forces (VGRFs) generated by feet-ground contact. This database comprises the VGRFs of four groups: amyotrophic lateral sclerosis, the control group, Huntington's disease, and Parkinson disease. The RF produced an overall classification accuracy of 91%, and the specificities and sensitivities for each class were between 80% and 100%. However, despite this high performance, the RF-generated models demonstrated lack of interpretability prompted the training of a CT using identical features. The obtained tree comprised only four features and required a maximum of three comparisons. However, this simplification dramatically reduced the overall accuracy from 90.6% to 62.3%. The proposed set features were compared with those included in PhysioNet database of VGRFs. In terms of both the RF and CT, more accurate models were established using our features than those of the PhysioNet.

Prosets: a new financing instrument to deliver a durable net zero transition

Interest in carbon offsetting is resurging among companies and institutions, but the vast majority of existing offerings fail to enable a credible transition to a durable net zero emission state. A clear definition of what makes an offsetting product “net zero compliant” is needed. We introduce the “proset”, a new form of composite carbon credit in which the fraction of carbon allocated to geological-timescale storage options increases progressively, reaching 100% by the target net zero date, generating predictable demand for effectively permanent CO2 storage while making the most of the near-term opportunities provided by nature-based climate solutions, all at an affordable cost to the purchaser.

Spotlight on Charge-Transfer Excitons in Crystalline Textured n-Alkyl Anilino Squaraine Thin Films

Prototypical n-alkyl terminated anilino squaraines for photovoltaic applications show characteristic double-hump absorption features peaking in the green and deep-red spectral range. These signatures result from coupling of an intramolecular Frenkel exciton and an intermolecular charge transfer exciton. Crystalline, textured thin films suitable for polarized spectro-microscopy have been obtained for compounds with n-hexyl (nHSQ) and n-octyl (nOSQ) terminal alkyl chains. The here released triclinic crystal structure of nOSQ is similar to the known nHSQ crystal structure. Consequently, crystallites from both compounds show equal pronounced linear dichroism with two distinct polarization directions. The difference in polarization angle between the two absorbance maxima cannot be derived by spatial considerations from the crystal structure alone but requires theoretical modeling. Using an essential state model, the observed polarization behavior was discovered to depend on the relative contributions of the intramolecular Frenkel exciton and the intermolecular charge transfer exciton to the total transition dipole moment. For both nHSQ and nOSQ, the contribution of the charge transfer exciton to the total transition dipole moment was found to be small compared to the intramolecular Frenkel exciton. Therefore, the net transition dipole moment is largely determined by the intramolecular component resulting in a relatively small mutual difference between the polarization angles. Ultimately, the molecular alignment within the micro-textured crystallites can be deduced and, with that, the excited state transitions can be spotted.

Solving the difficult problem of hard to decarbonize homes

Hard to decarbonize homes represent a complex problem that has historically been neglected in favour of the lower hanging fruit of easier to treat properties. To enable an equitable net zero transition, we must understand these homes in a holistic manner take into account the impacts of different routes to decarbonization on occupants.

Public perception of transitioning to a low-carbon nation: a Malaysian scenario

Efforts such as the Glasgow United Nations Climate Change Conference of the Parties 26, the Paris Agreement (Paris agreement, United Nations, Paris, 2015) and the United Nations Sustainable Development Goals are supporting the drive to protect the planet from global warming by ensuring sustainable development. The oil and gas industry, as key contributor to greenhouse gas emissions, must transition to more sustainable energy solutions and play their part in reducing these emissions. Currently, oil and gas companies are implementing technical solutions to achieve net zero carbon emissions. The energy transition from fossil fuel reliance has also happened by exploiting alternative renewable energy sources to meet global energy demand such as wind, solar, biogas and bioderived feedstocks. This net zero energy transition will require a fair and just transition for all in society, and to implement this, it is crucial for those working in the oil and gas industry to understand the technologies needed, the importance of carbon policies and their roles. This research presents a modified Delphi study of employees in Malaysia's national oil and gas company to understand their perceptions towards a net-zero carbon future. The paper briefly reviews Malaysia's low-carbon policy plans, its current carbon dioxide accounting balance, and identifies potential technologies for decarbonisation to set the scene for the modified Delphi study. The results indicated that the national oil and gas company has both the capabilities and the financial resources to significantly contribute towards Malaysia transitioning to a carbon neutral nation. This can be achieved by implementing advanced technologies complementing with nature-based solutions to realise net zero carbon emissions. This study also portrays the confidence that the portfolio of solutions should be executed through a coordinated effort to maximise the outcome and minimise the financial impact in terms of economical sustainability. Implementation of activities towards this energy transition will require significant social commitment, and hence, gauging their perception towards this journey is key objective of this paper.Graphical abstract

Impacts of Transition Approach of Water Vapor-Related Microphysical Processes on Quantitative Precipitation Forecasting

The water vapor-related microphysical processes (WVRMPs) in cloud microphysics schemes are crucial to the formation and dissipation of clouds, which have a significant impact on the quantitative precipitation forecasting of numerical weather prediction models. In this study, a well physics-based parallel-split transition approach (PSTA) to compute the WVRMPs from the same temperature and humidity state is developed and compared with the original sequential-update transition approach (SUTA) in a double-moment cloud microphysics scheme. Case study and batch experiments were carried out to investigate their different impacts on the clouds and precipitation simulated by the Global/Regional Assimilation and Prediction System (GRAPES) regional 3 km high-resolution model of the China Meteorological Administration (CMA), named CMA-MESO. The results show that the PSTA experiment tends to simulate a narrower and more concentrated precipitation area with a higher-intensity center compared to those of the SUTA experiment, which is more consistent with the observations. In the cold region, the net transition rates of WVRMPs from the PSTA experiment with more ice-phase hydrometeors are higher than those from the SUTA experiment. While in the warm region, the condensation and evaporation rates with violent fluctuation simulated by the SUTA are significantly larger than those from the PSTA experiment, resulting in less precipitation. The batch experiments indicate that the equitable threat scores (ETSs) of 24-h precipitation simulated by the PSTA are just slightly better than those of the SUTA, yet its ETSs of 48-h precipitation have been systematically improved for all magnitude levels against the SUTA. It is demonstrated that more attention should be paid to the reasonable treatments of the WVRMPs in developing cloud microphysics schemes.

Phasing out coal power plants based on cumulative air pollution impact and equity objectives in net zero energy system transitions

Abstract Transitioning to a net zero economy entails rapidly retiring US coal power plants, a major source of both greenhouse gases and air pollution. Conceptualizations of just transitions often embed climate, socioeconomic, and environmental justice objectives. Here we evaluate the influence of cumulative air pollution impact and equity objectives in the context of coal electric power plant retirement decisions. Operating coal power plants accounted for approximately 11 600 mortalities ($100B in damages) in 2018, disproportionately impacting low income, nonwhite, and rural populations. To evaluate the future phase-out of coal generators, we optimize for alternative climate policy goals, in addition to air pollution objectives related to the distribution of impacts on the basis of income, race, voting patterns, population density, and National Ambient Air Quality Standards classifications. With policy goals to both achieve net zero emissions by mid-century and to minimize cumulative air pollution-related mortality, approximately 134 000 deaths ($1.2T) are avoided from 2020 to 2050 (relative to business-as-usual). We find that the way in which equity objectives are operationalized has a large influence on asset-level retirement decisions and policy design. Phase-out strategies associated with policy objectives to minimize cumulative mortalities across the US population are generally consistent with objectives to minimize impacts on vulnerable subpopulations, but differ from those that target geographically-defined vulnerable communities.

Editorial: The ascent of green crime: exploring the nexus between the net zero transition and organized crime

Editorial: The ascent of green crime: exploring the nexus between the net zero transition and organized crime

Experimental study of electrical heating to enhance oil production from oil-wet carbonate reservoirs

New approaches for enhanced oil recovery (EOR) with a reduced environmental footprint are required to improve recovery from mature oil fields, and when combined with carbon capture and storage (CCS) can provide useful options for resource maximisation during the net zero transition. Electrical heating is investigated as a potential EOR method in carbonate reservoirs. Samples were placed in an apparatus surrounded by a wire coil across which different DC (direct current) voltages were applied. Monitoring the imbibition of both deionized water (DW) and seawater (SW) into initially oil-wet Austin chalk showed that water imbibed into the rock faster when heated in the presence of a magnetic field. This was associated with a reduction in the water–air contact angle over time measured on the external surface of the sample. Without heating, the contact angle reduced from 127° approaching water-wet conditions, 90°, in 52 min, while in the presence of heating with 3 V, 6 V, and 9 V applied across a sample 17 mm in length, the time required to reach the same contact angle was only 47, 38 and 26 min, respectively, while a further reduction in contact angle was witnessed with SW. The ultimate recovery factor (RF) for an initially oil-wet sample imbibed by DW was 13% while by seawater (SW) the recorded RF was 26% in the presence of an electrical heating compared with 2.8% for DW and 11% for SW without heating. We propose heating as an effective way to improve oil recovery, enhancing capillary-driven natural water influx, and observe that renewable-powered heating for EOR with CCS may be one option to improve recovery from mature oil fields with low environmental footprint.

Análisis espacial de los cambios de uso de suelo, vegetación y cuerpos de agua en el estado de Nayarit, México, 1993-2014

Para comprender plenamente la dinámica de cambio de uso de suelo es necesario investigar el cambio neto, los intercambios y las transiciones que ocurren entre categorías de uso del suelo. Por ello, esta investigación explora las tendencias espaciales y temporales de los cambios de uso del suelo, la vegetación y los cuerpos de agua en el estado de Nayarit. Para hacerlo, las series II y IV de INEGI fueron validadas en campo, remuestreadas y sobrepuestas en TerrSet GIS para calcular la matriz de cambio y a partir de ella estimar las pérdidas, las ganancias el cambio neto, así como el cambio total y el intercambio entre categorías. Los resultados indican que, de las 2 783 572.50 hectáreas de la superficie total, el 58.06% no sufrió ningún cambio, mientras que el 41.94% presentó algún cambio en la ocupación del suelo, del cual 15.42% corresponde a intercambios entre las categorías y 26,.52% es un cambio neto. La categoría que ganó más proporción del territorio fue la agricultura; que en 1993 ocupaba el 18.17% y en 2014 pasó al 22.14%. Por el contrario, la selva baja disminuyó de 20.82% a 13.76% durante el mismo período.

Impact on the power mix and economy of Japan under a 2050 carbon-neutral scenario: Analysis using the E3ME macro-econometric model

ABSTRACT This study uses the E3ME macro-econometric model to simulate what Japan’s macroeconomy would look like and how Japan's energy composition would change if the country were to achieve carbon neutrality by 2050. The results indicate that renewable energy will account for about 90% of the power supply configuration in 2050, assuming nuclear power plants are phased out by 2040. It is also predicted that GDP will increase by 4.0%–4.5% compared with the baseline scenario and that employment will improve by 1.5%–2.0%, resulting in simultaneous achievement of carbon neutrality and economic growth. The main reasons for these projected outcomes are that increased investment in renewable generation capacity in the power sector would be accompanied by increased investment in decarbonization technologies across individual economic sectors, increased private consumption resulting from increased employment and energy efficiency savings, and an improvement in the trade balance due to a substantial reduction in fossil fuel imports. In addition, the costs of energy due to policies to reduce or eliminate carbon would rise by 45%–55% point at most above the baseline scenario even in 2050; however, this would be of little burden on the economy, considering the substantial reduction in fossil fuel energy demand. Overall, it is estimated that energy bills would be 45% lower for consumers and 11% lower for industry in 2050 compared with the baseline. Key policy insights The study shows that achieving climate neutrality does not require difficult trade-offs with economic growth. Instead, it can provide economic opportunities that arise from switching to renewables and decarbonization technologies. The rapid reduction in global renewable costs for wind and solar technologies means that the net zero transition does not have to rely on relatively more expensive nuclear power. The true costs of nuclear could be a lot higher when the costs of safety regulations are properly accounted for. Instead, investment in electricity storage should be prioritized. A well balanced decarbonization policy mix for each sector is required. Policy makers should not rely on carbon pricing instruments alone. Supporting policies such as R&D spending, renewable subsidies, regulations and energy demand reduction should also be considered.

Environmental Sustainability and Supply Resilience of Cobalt

Cobalt (Co) is an essential metal for the development of energy-transition technologies, decarbonising transportation, achieving several sustainable development goals, and facilitating a future net zero transition. However, the supply of Co is prone to severe fluctuation, disruption, and price instabilities. This review aims to identify the future evolution of Co supply through technologically resilient and environmentally sustainable pathways. The work shows that advances in both primary and secondary sources, Co mining methods and recycling systems are yet to be fully optimised. Moreover, responsible sourcing from both large mines and small artisanal mines will be necessary for a resilient Co supply. Regulatory approaches may increase transparency, support local mining communities, and improve secondary Co recovery. Novel Co supply options, such as deep-sea mining and bio-mining of tailings, are associated with major techno-economic and environmental issues. However, a circular economy, keeping Co in the economic loop for as long as possible, is yet to be optimised at both regional and global scales. To achieve environmental sustainability of Co, economic incentives, regulatory push, and improved public perception are required to drive product innovation and design for circularity. Although the complexity of Co recycling, due to lack of standardisation of design and chemistry in batteries, is an impediment, a sustainable net zero transition using Co will only be possible if a reliable primary supply and a circular secondary supply are established.

Petri net-based object-centric processes with read-only data

During the last decade, various approaches have been put forward to integrate business processes with different types of data. Each of these approaches reflects specific demands in the whole process-data integration spectrum. One particularly important point is the capability of these approaches to flexibly accommodate processes with multiple case objects that need to co-evolve. In this work, we introduce and study an extension of coloured Petri nets, called catalogue and object-aware nets (COA-nets), providing two key features to capture this type of processes. On the one hand, net transitions are equipped with guards that simultaneously inspect the content of tokens and query facts stored in a read-only, persistent database. On the other hand, such transitions can inject data into tokens by extracting relevant values from the database or by generating genuinely fresh ones. We demonstrate that this class of nets can be used for representing various multi-case modelling scenarios involving objects with one-to-many correlations. We then study a parameterised verification problem of COA-nets and show how to systematically encode them into one of the reference frameworks for attacking that kind of problem in the context of infinite-state systems with data. We demonstrate that different fragments of COA-nets can have different expressive power that can affect the decidability of not only the verification problem at hand, but also the standard problem of place nonemptiness checking. Finally, we discuss how COA-nets relate to well-known formalisms in the area of multi-case and data-aware process modelling and analysis.