This article aims to describe the current state of research on plastic waste management as a circular economy practice at the end of the supply chain. The methodological strategy chosen was a systematic literature review. The articles selected from the Web of Science and Scopus databases were screened, and the research corpus consisted of 201 articles published in journals between 2014 and 2021. The results present 13 study categories, showing topics such as pyrolysis, business models, Industry 4.0, and energy generation. The insertion of Industry 4.0 technologies is still in its initial stages, comprising mainly the generation of inputs to reuse waste for 3D printers’ materials. Regarding energy generation, the insertion of processes such as pyrolysis for fuel generation stands out. The proposed discussion in this article suggests a circular ecosystem in which wastes follow a reuse flow according to their properties; incineration can be an option depending on the stage and benefits ge... [more]

The transition to a more environmentally friendly energy matrix by reducing fossil fuel usage has become one of the most important goals to control climate change. Variable renewable energy sources (VRES) are a central low-carbon alternative. Nevertheless, their variability and low predictability can negatively affect the operation of power systems. On this issue, energy-system-modeling tools have played a fundamental role. When exploring the behavior of the power system against different levels of VRES penetration through them, it is possible to determine certain operational and planning strategies to balance the variations, reduce the operational uncertainty, and increase the supply reliability. In many developing countries, the lack of such proper tools accounting for these effects hinders the deployment potential of VRES. This paper presents a particular energy system model focused on the case of Bolivia. The model manages a database gathered with the relevant parameters of the Bol... [more]

The emerging bioeconomy requires new supply chain paradigms for biomass materials to reach processing centers. Forest bio-hubs can be thought of as networks of collection points to facilitate biomass supply chains that feed from forest to central processing facilities. The design and functionality of forest bio-hubs depends on the form (e.g., vertically and horizontally integrated), and the quality and volume of feedstocks. In this paper we conceptually develop the potential role of forest bio-hubs. We then compare current bio-hub development in three U.S. regions—the Pacific Northwest, the southwest region, and the southeastern U.S. We use a “SWOT” framework to compare strengths, weaknesses, opportunities, and threats for each region. We consider transportation distances, topography, proximity to markets, harvesting methods, and wood products development. Innovation and adaptability would play key roles in forest bio-hub development, especially with dynamic conditions related to marke... [more]

The support offered to local authorities in this work consisted of technical and economic training on the integration of energy efficiency measures as well as the development of tools (guidelines, a decision support tool, databases and a visualization platform) that allow local authorities to prepare their building renovation plans. These tools are found very useful for local authorities, particularly in the case of Teruel province, characterised by many small municipalities whose local governments do not have the technical staff to undertake this type of planning. As a result of this work, an energy action plan was elaborated for the implementation of 96 energy efficiency measures in public buildings of Teruel province. The execution of this plan would allow energy savings of 1.3 MWh/year and 245 tonsCO2e/year of CO2 emission reduction, involving an investment of EUR 1.2 M. The close collaboration with public authorities made it possible to assess the strengths and weaknesses of using... [more]

Reasonable regional integrated energy planning is an important prerequisite for the construction of a Near-Zero Carbon Emission Demonstration District (NCEDD). An integrated energy planning scheme that is based on a three-step planning method with the objective of achieving an NCEDD is proposed in this paper. First, the planning objectives should be determined. After that, the planning strategies should be established. Finally, the planning approaches should be proposed according to the previously determined objectives and strategies. A case study considering the integrated energy planning of the Meishan International Near-Zero Carbon Emission Demonstration District (MINCEDD) is investigated to explain the planning method. In addition, the planning results, which are indicated as indexes, are explained, analyzed, and compared to the ones of other districts. The indexes include a proportion of renewable energy to primary energy (73% by 2030 and 108% by 2050), a proportion of renewable p... [more]

Future low-carbon systems with very high shares of variable renewable generation require complex models to optimise investments and operations, which must capture high degrees of sector coupling, contain high levels of operational and temporal detail, and when considering seasonal storage, be able to optimise both investments and operations over long durations. Standard energy system models often do not adequately address all these issues, which are of great importance when considering investments in emerging energy carriers such as Hydrogen. An advanced energy system model of the Irish power system is built in SpineOpt, which considers a number of future scenarios and explores different pathways to the wide-scale adoption of Hydrogen as a low-carbon energy carrier. The model contains a high degree of both temporal and operational detail, sector coupling, via Hydrogen, is captured and the optimisation of both investments in and operation of large-scale underground Hydrogen storage is d... [more]

The power demand on the electric grid varies according to the time of the day following users’ needs and so does the cost of electricity supply because the electricity mix is formed using different generators of varying capacities. Demand response (DR) is the modification of the consumption load curve following a signal from the electricity provider; it is mostly used for peak clipping. By reducing the short-term mismatch between generation and consumption, it helps to integrate intermittent renewables and new low-carbon technologies such as energy storage, electric vehicles, and power-to-gas. The present work is a literature survey based on the following keywords: demand response, demand technology, potential, power, and power dispatch, which aims to provide a summary of the state of the art regarding the potential for demand response implementation. Literature is either related to potential assessment or to implementation; less focus is given on non-dispatchable DR than on dispatchab... [more]

In the acceleration phase transitions often increase in depth and scope, and thereby create knock-on effects for wider system structures. In the renewable energy transition, for example, higher shares of intermittent renewable energy sources call for new grid technologies to increase flexible grid operation. At the same time, there are different ways of achieving renewable energy transitions and providing flexibility. In Europe, important tensions exist over how centralised or decentralised a renewable energy electricity system should be. This paper explores to what extent and how European framework programmes for research and development have addressed and supported innovation in transmission grid (centralised system) and distribution grid (decentralised) technologies. We analyse European R&D projects that studied electricity grid planning, development and innovation over 2002−2020. We apply social network analysis of the collaboration partners in these projects, and analyse the calls... [more]

The key direction of political actions in the field of sustainable development of the energy sector and economy is the process of energy transformation (decarbonization) and increasing the share of renewable energy sources (RES) in the supply of primary energy. Regardless of the indisputable advantages, RES are referred to as unstable energy sources. A possible solution might be the development of the concept of hydrogen supply chains, especially the so-called green hydrogen obtained in the process of electrolysis from electricity produced from RES. The aim of the research undertaken in the article is to identify the scope of research carried out in the area of hydrogen supply chains and to link this research with the issues of the operation of electricity distribution networks powered by RES. As a result of the scoping review, and the application of the text-mining method using the IRaMuTeQ tool, which includes the analysis of the content of 12 review articles presenting the current r... [more]

Ultra-fast charging infrastructures are gaining increasing interest thanks to their ability to reduce the charging-time of plug-in electric vehicles to values comparable to those of the refueling of traditional vehicles in gas stations. This is a consequence of the increasing rated power of both on-board batteries and charging equipment. On the other hand, the increased values of charging power have led to an increased impact on the power distribution networks, particularly in terms of line currents and bus voltages. In presence of large penetration of ultra-fast charging devices, in fact, both currents and voltages are affected by larger variations whose values can exceed the admissible limits imposed by the technical constraints and by the levels of quality of service. In order to reduce the impact of this typology of vehicles’ charging on the electrical infrastructure, in this paper a methodology is presented which allows managing a microgrid in presence of ultra-fast charging stati... [more]

The International Maritime Organisation (IMO) calls for the maritime industry to restrict its CO2 emissions by −40% (IMO2030) and −70% (IMO2050). This paper answered the following research question: “Which technical, economic and emissions-related conditions predominantly determine the feasibility of a conceptual supply chain of liquid CO2 that is captured from the exhaust gases of LNG powered offshore vessels?” The captured CO2 is transported to land where it is utilized by a final customer. The study followed a systems engineering approach. Problem definition was followed by a requirements analysis (technology, emissions, economy and operations), design with scenarios and a case study with realistic vessel deployment, modeling and evaluation. All designs have technical uncertainties and financial risks, but the sale of captured CO2 could be a crucial advantage of the proposed concept over other concepts. The main conclusion is that emission and financial targets (payback time) can be... [more]

In Nigeria, the high dependence on fossil fuels for energy generation and utilization in various sectors of the economy has resulted in the emission of a large quantity of carbon dioxide (CO2), which is one of the criteria gaseous pollutants that is frequently encountered in the environment. The high quantity of CO2 has adverse implications on human health and serious damaging effects on the environment. In this study, multi-decade (1971−2014) CO2-emissions data for Nigeria were obtained from the World Development Indicator (WDI). The data were disaggregated into various emission sources: gaseous fuel consumption (GFC), liquid fuel consumption (LFC), solid fuel consumption (SFC), transport (TRA), electricity and heat production (EHP), residential buildings and commercial and public services (RSCPS), manufacturing industries and construction (MINC), and other sectors excluding residential buildings and commercial and public services (OSEC). The analysis was conducted for a sectorial tre... [more]

The increased popularity of small-scale DER has replaced the well-established concept of conventional generating plants around the world. In the present energy scenario, a significant share of energy production now comes from the grid integrated DERs installed at various consumer premises. These DERs are being renewable-based generates only intermittent power, which in turn makes the scheduling of electrical dispatch a tough task. The Virtual Power Plant (VPP) is a potential solution to this challenge, which coordinates and aggregates the DERs generation into a single controllable profile. In this paper, a modified PSO-based multi-objective optimization is proposed for the VPP scheduling in distribution network applications such as energy cost minimization, peak shaving, and reliability improvement. For feasibility analysis of the VPP, a case study of state power utility is taken, which includes a 90 bus industrial feeder with grid integrated PVs as DER. The optimized results are compu... [more]

Offshore sites show greater potential for wind energy utilization than most onshore sites. When planning an offshore wind power farm, the speed of offshore wind is used to estimate various operation parameters, such as the power output, extreme wind load, and fatigue load. Accurate speed prediction is crucial to the running of wind power farms and the security of smart grids. Unlike onshore wind, offshore wind has the characteristics of random, intermittent, and chaotic, which will cause the time series of wind speeds to have strong nonlinearity. It will bring greater difficulties to offshore wind speed predictions, which traditional recurrent neural networks cannot deal with for lacking in long-term dependency. An offshore wind speed prediction method is proposed by using a clockwork recurrent network (CWRNN). In a CWRNN model, the hidden layer is subdivided into several parts and each part is allocated a different clock speed. Under the mechanism, the long-term dependency of the recu... [more]

In the process of transportation system construction, the tunnel is always an indispensable part of the traffic network due to terrain constraints. A collapse of the tunnel under construction may give rise to a potential for significant damage to the traffic network, complicating the road conditions and straining relief services for construction workers. To cope with the variety of vehicle types during the rescue effort, this paper divides them into small, medium, and large sizes, herein correcting the corresponding speed considering six road condition factors on account of the previous research. Given the influence of different special road conditions on the speed of different sized vehicles, a multi-objective model which contains two stages is presented to make decisions for rescue vehicle scheduling. Under the priority of saving human life, the first-stage objective is minimizing the arrival time, while the objective of the second stage includes minimizing the arrival time, unmet de... [more]

The interdependency of electric and natural gas systems is becoming stronger. The challenge of how to meet various energy demands in an integrated energy system (IES) with minimal cost has drawn considerable attention. The optimal scheduling of IESs is an ideal method to solve this problem. In this study, a day-ahead optimal scheduling model for IES that included an electrical system, a natural gas system, and an energy hub (EH), was established. The proposed EH contained detailed models of the fuel cell (FC) and power to gas (P2G) system. Considering that the optimal scheduling of an IES is a non-convex complex optimal problem, a piecewise self-adaptive particle swarm optimization (PCAPSO) algorithm based on multistage chaotic mapping was proposed to solve it. The objective was to minimize the operating cost of the IES. Three operation scenarios were designed to analyze the operation characteristics of the system under different coupling conditions. The simulation results showed that... [more]

In flood control scheduling of reservoirs, the usual conventional scheduling fails to obtain the optimal solution to the problem. The dynamic programming method is applied to the field. However, the problem of ‘dimensional disaster’ restricts its application. To solve these problems, the improved DP is constructed according to the principle of period inflow and water balance, which includes a variable dispersion mechanism of the retraction space and a calculation method for the smallest discrete points of each discrete range. Taking Dongjiang Reservoir as the research object, based on the maximum peak clipping criterion and the maximum flood control safety guarantee criterion, the improved DP is used for optimization. The results find that when the former criterion is used for scheduling, the discharge flow processes of the two floods are more uniform than conventional scheduling. When the latter criterion is used for scheduling, the minimum water levels of the two floods are lower tha... [more]

Workforce planning is essential in today’s business management. If an organization can find and keep enough staff who have the right values, then they can provide high-quality service. This paper presents a workforce planning framework for selecting the best forecasting model in order to provide minimum wage and computer electricity costs for a mobile call center during the Songkran festival event, and to optimize workforce planning. The framework is constructed with four main steps: a study of a separate period; the separation of models with different data types; the simulation of models under different service levels to determine the number of customers waiting in a call center; and the evaluation of the models. The results from the proposed framework presented the best forecasting method and the optimal workforce plan. It is clear that this approach can assist in systematically selecting the best forecasting model. In addition, a workforce planner can use this framework to support w... [more]

In modern electrical grids, the number of nonlinear grid elements and actively controlled loads is rising. Maintaining the power quality will therefore become a challenging task. This paper presents a power quality mitigation method via smart demand-side management. The mitigation method is based on a genetic algorithm guided optimization for smart operational planning of the grid elements. The algorithm inherits the possibility to solve multiple, even competing, objectives. The objective function uses and translates the fitness functions of the genetic algorithm into a minimization or maximization problem, thus narrowing down the complexity of the addressed high cardinality optimization problem. The NSGA-II algorithm is used to obtain feasible solutions for the auto optimization of the demand-side management. A simplified industrial grid with five different machines is used as a case study to showcase the minimization of the harmonic distortion to normative limits for all time steps d... [more]

The collaborative planning of a wind-photovoltaic (PV)-energy storage system (ESS) is an effective means to reduce the carbon emission of system operation and improve the efficiency of resource collaborative utilization. In this paper, a wind-PV-ESS collaborative planning strategy considering the morphological evolution of the transmission and distribution network is proposed. Firstly, aiming at the optimal economy of transmission and distribution network and considering the constraints of safe and stable operation of the system, the planning model of the transmission network based on DC power flow and the planning model of the distribution network based on AC power flow are constructed. Further, considering the coupling interaction between the transmission and distribution networks, a collaborative planning model of transmission and distribution networks based on second-order cone relaxation (SOCR) is constructed. Secondly, in order to reduce the computational complexity of the model... [more]

This review paper examines the key barriers to using green ammonia as an alternative fuel in maritime industry. A literature survey is performed based on research articles and grey literature, with the aim of discussing the technoeconomic problems with and benefits of ammonia and the relevant technologies. The limitations of ammonia as a maritime fuel and its supply chain, the expected percentage demand by 2030 and 2050, its economic performance compared to other shipping fuels such as hydrogen, and the current regulations that may impact ammonia as a maritime fuel are discussed. There are several key barriers to ammonia’s wide adoption: (1) High production costs, due to the high capital costs associated with ammonia’s supply chain; (2) availability, specifically the limited geographical locations available for ammonia bunkering; (3) the challenge of ramping up current ammonia production; and (4) the development of ammonia-specific regulations addressing issues such as toxicity, safety... [more]

Electrical energy is critical to a country’s socioeconomic progress. Distribution system expansion planning addresses the services that must be installed for the distribution networks to meet the expected load need, while also meeting different operational and technical limitations. The incorporation of distributed generation sources (DGs) alters the operating characteristics of modern power systems, resulting in major economic and technical benefits, such as simplified distribution network expansion planning, lower power losses, and improved voltage profile. Thus, in this study, an analytical method is used to design the expansion planning of the Addis North distribution network considering the integration of optimal sizes of distributed generations for the projected demand growths. To evaluate the capability of the existing Addis North distribution network and its capability to supply reliable power considering future expansion, the load demand forecast for the years 2020−2030 is don... [more]

The objective of the paper is to present an original (own) concept of a model profile of a sustainable manager from the sustainability perspective and then confront this model profile with the opinions of managers employed in energy companies. This problem domain has not been reflected in the scientific literature. Sustainable managers are the ones who are fully prepared to implement the principles of sustainability in energy companies, respecting the principles of sustainable management. Their activity can, to a considerable extent, accelerate sustainable development. According to the model profile, a sustainable manager should be sensitive to ecological and social problems; be knowledgeable about sustainability and demand the same from subordinates; comply with ethical standards; implement pro-environmental and pro-social innovations; and also plan, organize, motivate, and control the contribution, in this way, to sustainable development. Research was conducted aimed at discovering t... [more]

Mobile robot path planning has passed through multiple phases of development and took up several challenges. Up to now and with the new technology in hands, it becomes less complicated to conduct path planning for mobile robots and avoid both static and dynamic obstacles, so that collision-free navigation is ensured. Thorough state of the art review analysis with critical scrutiny of both safe and optimal paths for autonomous vehicles is addressed in this study. Emphasis is given to several developed techniques based using sampling algorithms, node-based optimal algorithms, mathematic model-based algorithms, bio-inspired algorithms, which includes neural network algorithms, and then multi-fusion-based algorithms, which combine different methods to overcome the drawbacks of each. All of these approaches consider different conditions and they are used for multiple domains.

With the restructuring of the power system, household-level end users are becoming more prominent participants by integrating renewable energy sources and smart devices and becoming flexible prosumers. The use of microgrids is a way of aggregating local end users into a single entity and catering for the consumption needs of shareholders. Various microgrid architectures are the result of the local energy community following different decarbonisation strategies and are frequently not optimised in terms of size, technology or other influential factors for energy systems. This paper discusses the operational and planning aspects of three different microgrid setups, looking at them as individual market participants within a local electricity market. This kind of implementation enables mutual trade between microgrids without additional charges, where they can provide flexibility and balance for one another. The developed models take into account multiple uncertainties arising from photovolt... [more]