Coal’s green mining and scientific utilization is the key to achieve the national vision of carbon peak by 2030 and carbon neutrality by 2060. Clarifying the CO2 flow of coal production is the core part of decarbonization. This study uses an environmental extended multi-regional input−output (EEMRIO) model to analyze the impact of embodied emissions on the indirect CO2 emission intensity of coal production between China’s coal mining sector and 141 countries/regions. It is found that the CO2 emission intensity of China’s coal production was 34.14 gCO2/MJ in 2014, while the direct and indirect emission intensities were 16.22 gCO2/MJ and 17.92 gCO2/MJ, respectively. From 2007 to 2014, the direct emission intensity of China’s coal production increased by 23%, while the indirect emission intensity decreased by 30%. The key material and service inputs affecting indirect carbon emissions of coal production in China are electricity service, metal manufacturing, chemical products, coal mining,... [more]

This paper is a review of research undertaken, and subsequent policy change enacted, in the years 2018 to 2022 regarding the integration of cooking loads and needs into modern energy planning. Building on an earlier paper which described how the dominant global approaches to tackling the enduring problem of biomass-fuelled cooking was failing, and how a new UK Aid programme (Oct 2018) would be seeking to intentionally change international energy policy towards cooking and enable a significant transition in energy use, in this paper we review whether this strategy is being adopted by researchers, governments, and the private sector across the world and whether it is likely to make a significant contribution to the fulfilment of Sustainable Development Goal 7. In particular, the call is for integrated planning of modern energy inclusive of cooking loads—the potential ‘Mutual Support’ that both can lend to each other. The review considers the international commitments made by donors and g... [more]

In recent years, carbon cap-and-trade has been promoted by many national governments aiming to limit, or cap, total carbon dioxide emissions. Such a mechanism impacts manufacturers’ remanufacturing decisions, as it increases the cost of carbon emissions. The current literature has recognized the importance of carbon cap-and-trade regulations; however, little attention has been paid to what effect such regulations have on manufacturer’s remanufacturing with the flexibility to engage it in-house or outsource it to third-party remanufacturers. To fill this gap, we develop two theoretical models that, under the carbon cap-and-trade mechanism, allow the manufacturer to engage in remanufacturing operations in-house (Model H) or outsource them to an independent remanufacturer (Model R). The primary goal of this paper is to understand what effects carbon cap-and-trade regulations have on green supply chain management when producing new and remanufactured products. In particular, we find that a... [more]

The high energy consumption of desalination systems represents a significant opportunity for the application of demand response schemes, particularly for the case of Non-Interconnected Island (NII) systems. In particular, the optimal management of the desalination demand can be proven quite beneficial in increasing the Renewable Energy Sources’ (RES) penetration, which is one of the main objectives in the day-ahead scheduling of the electricity system in Greek NIIs. This paper proposes a detailed representation of the desalination system, taking into account all the relevant constraints for the system’s operation. The mathematical representation of the aforementioned operation is incorporated in the day-ahead scheduling (DAS) for the case of Greek NII systems in order to define the optimal operational scheduling of a desalination system. The proposed optimisation procedure is applied for the desalination system installed in the Greek island of Kythnos. The results of the analysis indic... [more]

The efficient management of water and energy is one challenge for managers of water pressurized systems. In a scheme with high pressure on the environment, solar power appears as an opportunity for nonrenewable energy expenditure reduction and emissions elimination. In Spain, new legislation that eliminates old taxes associated with solar energy production, a drop in the cost of solar photovoltaic modules, and higher values of irradiance has converted solar powered water systems into one of the trendiest topics in the water industry. One alternative to store energy (compulsory in standalone photovoltaic systems) when managing pressurized urban water networks is the use of head tanks (tanks accumulate water during the day and release it at night). This work intends to compare the pressurized network running as a standalone system and a hybrid solution that incorporates solar energy supply and electricity grids. The indicator used for finding the best choice is the net present value for... [more]

Energy consumption is a critical issue for the communications network operators, impacting deeply the cost of the services, as well as the ecological footprint. Network slicing architecture for 5G mobile communications enables multiple independent virtual networks to be created on top of a common shared physical infrastructure. Each network slice needs different types of resources, including energy, to fulfill the demands requested by each application, operator, or vertical market. The existing literature on network slicing is mainly targeted at the partition of network resources; however, the corresponding management of energy consumption is an unconsidered critical concern. This paper analyzes the requirements for an energy-aware 5G network slicing provisioning according to the 3GPP specifications, proposes an architecture, and studies the strategies to provide efficient energy consumption in terms of renewable and non-renewable sources. NFV and SDN technologies are the essential ena... [more]

In this work, we review papers that employ game theoretic tools to study the operation and design of modern electric grids. We consider four topics in this context: energy trading, energy balancing, grid planning, and system reliability, and we demonstrate the advantages of using game-theoretic approaches for analyzing complex interactions among independent players. The results and conclusions provide insights regarding many aspects of design and operation, such as efficient methodologies for expansion planning, cyber-security, and frequency stability, or fair-benefit allocation among players. A central conclusion is that modeling the system from the perspective of one entity with unlimited information and control span is often impractical, so correct modeling of the selfish behavior of independent players may be critical for the development of future power systems. Another conclusion is that correct usage of incentives by appropriate regulation or sophisticated pricing mechanisms may... [more]

In the grid-tied micro-grid context, energy resilience can be defined as the time period that a local energy system can supply the critical loads during an unplanned upstream grid outage. While the role of renewable-based micro-grids in enhancing communities’ energy resilience is well-appreciated, the academic literature on the techno-economic optimisation of community-scale micro-grids lacks a quantitative decision support analysis concerning the inclusion of a minimum resilience constraint in the optimisation process. Utilising a specifically-developed, time-based resilience capacity characterisation method to quantify the sustainability of micro-grids in the face of different levels of extended grid power outages, this paper facilitates stakeholder decision-making on the trade-off between the whole-life cost of a community micro-grid system and its degree of resilience. Furthermore, this paper focuses on energy infrastructure expansion planning, aiming to analyse the importance of m... [more]

Hybrid energy systems (HESs) generate electricity from multiple energy sources that complement each other. Recently, due to the reduction in costs of photovoltaic (PV) modules and wind turbines, these types of systems have become economically competitive. In this study, a mathematical programming model is applied to evaluate the techno-economic feasibility of autonomous units located in two isolated areas of Ecuador: first, the province of Galapagos (subtropical island) and second, the province of Morona Santiago (Amazonian tropical forest). The two case studies suggest that HESs are potential solutions to reduce the dependence of rural villages on fossil fuels and viable mechanisms to bring electrical power to isolated communities in Ecuador. Our results reveal that not only from the economic but also from the environmental point of view, for the case of the Galapagos province, a hybrid energy system with a PV−wind−battery configuration and a levelized cost of energy (LCOE) equal to 0... [more]

Distributed energy storage may play a key role in the operation of future low-carbon power systems as they can help to facilitate the provision of the required flexibility to cope with the intermittency and volatility featured by renewable generation. Within this context, this paper addresses an optimization methodology that will allow managing distributed storage systems of different technology and characteristics in a specific distribution network, taking into account not only the technical aspects of the network and the storage systems but also the uncertainties linked to demand and renewable energy variability. The implementation of the proposed methodology will allow facilitating the integration of energy storage systems within future smart grids. This paper’s results demonstrate numerically the good performance of the developed methodology.

Various high-temperature superconducting (HTS) power cables are being developed or are ready for commercial operation to help energy suppliers meet the growing power demand in urban areas. Recently, triaxial HTS power cables have been developed by Korea Electric Power Corporation (KEPCO) and LS Cable & System. Further, KEPCO has been planning to install a 2 km long 23 kV/60 MVA triaxial HTS power cable to connect the Munsan and Seonyu substations and increase the stability of the power grid. The HTS power cables should be cooled down to a cryogenic temperature near 77 K. A thermo-hydraulic analysis of the cooling system considering the geographical characteristics of the installation site is essential for long-distance sections. This paper describes the thermo-hydraulic analysis of the triaxial HTS power cable to determine the proper mass flow rates of subcooled liquid nitrogen that meet the operating temperature and pressure of the cable for four configurations of cooling systems: (1)... [more]

As an important supply chain development strategy, green investment and sustainability are concerns of the government and enterprises. However, due to the high cost and low profit of green investment, a large number of small and medium-sized firms can be deterred from their implementation. Value co-creation has become a key measure to solve this problem. This article explores the relationship between the green supply chain (GSC) strategy, value co-creation, and corporate performance in the manufacturing environment, and considers the regulatory effects of internal environmental factors and external environmental pressures on this relationship. Based on data from 115 manufacturers in China, we tested the hypotheses, explained the statistical results, and identified key concerns for implementing GSC through value co-creation. The findings reveal that the GSC strategy can promote a high level of firms’ value co-creation with their supply chain partners, and different value co-creation mod... [more]

Asset-management accounts for a significant share of grid operators’ influenceable costs, which are under high economic pressure due to deregulation. In asset-management, visual inspections are the main measure to determine asset conditions. In the context of digitalization, we propose a concept to acquire additional information about the condition of distribution substations and to derive flexible inspection intervals from this information, in contrast to fixed intervals that are common in scientific literature and practice. Thus, knowledge about the substations increases, inspection intervals can be expanded dynamically, and significant cost savings are possible, which we demonstrate by the example of a German distribution grid operator.

Coherent wind doppler lidar (CWDL) is a cost-effective way to estimate wind power potential at hub height without the need to build a meteorological tower. However, fog and low stratus (FLS) can have a negative impact on the availability of lidar measurements. Information about such reductions in wind data availability for a prospective lidar deployment site in advance is beneficial in the planning process for a measurement strategy. In this paper, we show that availability reductions by FLS can be estimated by comparing time series of lidar measurements, conducted with WindCubes v1 and v2, with time series of cloud base altitude (CBA) derived from satellite data. This enables us to compute average maps (2006−2017) of estimated availability, including FLS-induced data losses for Germany which can be used for planning purposes. These maps show that the lower mountain ranges and the Alpine regions in Germany often reach the critical data availability threshold of 80% or below. Especially... [more]

Oil plays an important role in global resource allocation. With the continuous development of the global supply chain, trade has brought a great impact on oil consumption. However, few studies have been focused on the oil consumption embodied in trade, that is, the oil footprints. Therefore, based on the multi-regional input-output model and structural decomposition model, this paper investigates the evolution and driving factors of the oil footprint between the two countries with the largest oil consumption in the world (China and the United States). By measuring the flow of oil footprint in bilateral trade, their trade transactions are analyzed at the national and industry levels. The results show that in Sino-US trade, China is a net exporter of virtual oil and the trade surplus is huge. The United States is the main destination of China’s virtual oil consumption exports. In 2004, China’s embodied oil net exports flowing into the US even exceeded its total net exports. Low value-add... [more]

Off-gas is one of the by-products of the steelmaking process. Its potential energy can be transformed into heat and electricity by means of cogeneration. A case study using a coke oven and Linz−Donawitz converter gas is presented. This work addresses the gas allocation problem for a cogeneration system producing steam and electricity. In the studied facility, located in northern Spain, the annual production of the plant requires 95,000 MWh of electrical energy and 525,000 MWh of thermal energy. The installed electrical and thermal power is 20.4 MW and 81 MW, respectively. A mixed integer linear programming model is built to optimize gas allocation, thus maximizing its benefits. This model is applied to a 24-h scenario with real data from the plant, where gas allocation decision-making was performed by the plant operators. Application of the model generated profit in a scenario where there were losses, increasing benefits by 16.9%. A sensitivity analysis is also performed. The proposed... [more]

The introduction of parametric tools has made a strong shift within a traditional approach to urban planning and building design, including the creation of a design awareness zone where environmental issues are concerned. This approach also uses sufficient data to be used already at the concept stage and provides initial interdisciplinary solutions. Analyses from the very initial stages allow the inclusion of smart energy choices influencing the massing, architectural features, proportions, flexibility of design, and economics. This is only a threshold; there is still a place for further development and more accurate analyses leading to the construction of buildings and urban areas with a stronger input of sustainable solutions, as existing approaches have certain limitations. This path has been followed in several research grants conducted at the Faculty of Architecture Warsaw University of Technology, and later on developed as a co-operation area with various stakeholders. Outside th... [more]

The current European policy roadmap aims at forcing the TSOs to coordinate remedial actions used for relieving the congestions in the synchronous power system. In this paper, an optimization problem for coordinated congestion management is described and its results obtained for a real European use cases created in the H2020 EU-SysFlex project are presented. First of all, these results prove the feasibility of a central optimization problem for the coordination of the cross-border congestion management process. Next, the formulated optimization problem is used to tackle the issue of planning the investments in phase-shifting transformers (PSTs), for the purpose of increasing the efficiency/decreasing the cost of congestion management. Finally, this paper introduces two optimization-based indicators for pre-selecting the investment sites, which may be used to support the decision makers aiming at decreasing the costs of coordinated congestion management.

This paper investigates the problem of power portfolio selection under uncertainty using two different metrics, namely the stochastic Net Present Value (NPV) and the stochastic Levelized Cost of Electricity (LCOE). In the first metric, stochastic revenues, as well as stochastic costs incurred during the whole lifetime of power plants, are taken into account. The second metric is based on stochastic costs only. This means that revenues deriving from selling electricity in power markets over long-term horizons play an important role in determining optimal portfolios under the stochastic NPV metric, but they have no impact on optimal portfolios under the stochastic LCOE metric. Uncertainty arising from unpredictable movements of electricity market prices, fossil fuels, and nuclear fuel prices is considered. Moreover, stochastic CO 2 costs are included into the analysis. The aim of this study was to examine in what circumstances efficient NPV-based portfolios differ in a significan... [more]

With an increasing interest in offshore wind energy, focus has been directed towards large semi-enclosed basins such as the Baltic Sea as potential sites to set up wind turbines. The meteorology of this inland sea in particular is strongly affected by the surrounding land, creating mesoscale conditions that are important to take into consideration when planning for new wind farms. This paper presents a comparison between data from four state-of-the-art reanalyses (MERRA2, ERA5, UERRA, NEWA) and observations from LiDAR. The comparison is made for four sites in the Baltic Sea with wind profiles up to 300 m. The findings provide insight into the accuracy of reanalyses for wind resource assessment. In general, the reanalyses underestimate the average wind speed. The average shear is too low in NEWA, while ERA5 and UERRA predominantly overestimate the shear. MERRA2 suffers from insufficient vertical resolution, which limits its usefulness in evaluating the wind profile. It is also shown tha... [more]

In any electric power system, the Transmission System Operator (TSO) requires the use of short-term load forecasting algorithms. These predictions are essential for appropriate planning of the energy resources and optimal coordination for the generation agents. This study focuses on the development of a prediction model to be applied to the ten main Spanish islands: seven insular systems in the Canary Islands, and three systems in the Balearic Islands. An exhaustive analysis is presented concerning both the estimation results and the forecasting accuracy, benchmarked against an alternative prediction software and a set of modified models. The developed models are currently being used by the Spanish TSO (Red Eléctrica de España, REE) to make hourly one-day-ahead forecasts of the electricity demand of insular systems.

The UN Paris Agreement of November 2016 recognises the need for a ‘cleaner and more efficient energy system’ as a core policy goal to address climate change. The spatial and urban form of cities is a key factor in achieving more efficient energy production and consumption and becomes more important with rapid urbanisation across much of the world. City urban form and planning are therefore potentially powerful levers for the energy transition. This paper examines the extent to which city ‘energy strategies’ address the critical spatial and urban form characteristics of cities as a means to achieve a more efficient energy system. We construct an assessment framework of key aspects of the spatial and urban development of cities related to transport and accessibility and urban form. The framework is used to assess the degree to which energy strategies take into consideration aspects of urban development in four cities that are taking significant action on the energy policy: Hong Kong Oakl... [more]

Distributed wind power (DWP) needs to be consumed locally under a 110 kV network without reverse power flow in China. To maximize the use of DWP, this paper proposes a novel method for capacity planning of DWP with participation of the energy storage system (ESS) in multiple scenarios by means of a variable-structure copula and optimization theory. First, wind power and local load are predicted at the planning stage by an autoregressive moving average (ARMA) model, then, variable-structure copula models are established based on different time segment strategies to depict the correlation of DWP and load, and the joint typical scenarios of DWP and load are generated by clustering, and a capacity planning model of DWP is proposed considering investment and operation cost, and environmental benefit and line loss cost under typical scenario conditions. Moreover, a collaborative capacity planning model for DWP and ESS is prospectively proposed. Based on the modified IEEE-33 bus system, the r... [more]

Growing penetration of uncoordinated Distributed Energy Resources (DERs) in distribution systems is contributing to the increase of the load variability to be covered at the transmission system level. Forced, fast and substantial changes of power plants’ output powers increase the risk of their failures, which threatens the reliable and safe delivery of electricity to end users in the power system. The paper handles this issue with the use of DERs and proposes a bilevel coordination concept of day-ahead operation planning with new kind of bids to be submitted by Distribution System Operators (DSOs) to the Transmission System Operator (TSO). This concept includes the extension of the Unit Commitment problem solved by TSO and a new optimization model to be solved by DSO for planning a smoothed power profile at the Transmission−Distribution (T−D) interface. Both optimization models are described in the paper. As simulations show, the modified 24-h power profiles at T−D interfaces result i... [more]

Smart energy transition efforts at the municipal level are gaining importance and go far beyond implementing single projects. Decarbonising cities involves complex strategic planning and needs system level thinking and changes. This has been increasingly realised at the municipal level, but challenges remain regarding the tools, involvement of stakeholders and on the development of policies. The focus of the research is on the use of participatory foresight for fostering smart energy transition on a municipal level, the key benefits and success factors that participatory foresight brings, and the replicability of this approach. Within the novel Cities4ZERO framework, an overarching methodology for a smart urban decarbonisation transition, guiding cities through the process of developing the most appropriate strategies, plans, projects, as well as looking for the commitment of key local stakeholders for an effective transition−foresight framework, was developed and tested in five pilot... [more]