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Steam is an important medium for energy transmission in industrial parks. For providing steam to multiple users, it is key to determine the optimal number of steam levels in the design of steam system. With the increasing number of steam levels, the energy demand and supply can be better matched but the investment of steam pipeline network increases. In this paper, this trade-off is solved by a two-stage method. In the first step, a mixed-integer nonlinear programming (MINLP) model is established to minimize the total cost of the steam system of the industrial park, while a simple pipeline network optimization model is involved. The optimal scheme of steam production including the number of steam levels can be obtained automatically. In the second step, GeoSteiner algorithm is used for solving Rectilinear Steiner Minimum Tree (RSMT) model to further optimize the pipeline network separately. In a case study, the optimal number of steam levels is 3. The total annual cost (TAC) of the optimal steam system is 11.4%, 5.28%, and 1.43% lower than the schemes with the lowest pipeline network cost (1 level of steam), the best matching between heat supply and heat demand (6 levels of steam), and the largest electricity generation capacity (4 levels of steam), respectively. The sensitivity analysis indicates that the overall heat load required by consumers and the distance between the energy station and consumers can make a difference to the optimal number of steam levels. • Steam production and steam supply in industrial park are optimized simultaneously. • Trade-off between electricity generation and pipeline cost is considered. • Effects of the load and distance of consumers and economic parameters are discussed. [ABSTRACT FROM AUTHOR]

This article analyzed the location and concentration of forest bioelectricity in Brazil, from 2000 to 2019, available from the National Electric Energy Agency (ANEEL) and used the following indicators: Location Quotient (QL), Concentration Index [CR (k)], Herfindahl-Hirschman Index (HHI), Hoover Index (H) and Coefficient of Gini (G). The main results showed that the supply of electricity from Brazilian forest biomass increased from 562.90 MW and 11 thermoelectric plants in 2000 to 3532.61 MW and 115 thermoelectric plants in 2019, providing an average growth of 10.15% yy of the granted installed power and 13.20% p.a. of thermoelectric power plants. The QL inferred a high concentration of energy supply from black liquor (Rio Grande do Sul, Paraná, Espírito Santo, Bahia, Maranhão and Mato Grosso do Sul) and forest residues in several states, mainly in the North region. At the state level, the CR (4), CR (8) and HHI indexes indicated a deconcentration trend. The identification of the location and concentration pattern that the greatest offer was associated with industrial pulp and paper complexes. These results can indicate to investors the impact of electric power generation in the sector and the most relevant location for the installation of new thermoelectric plants. [ABSTRACT FROM AUTHOR]

At present, energy represents a key element in the social and economic development of a territory. This is particularly true for fragile territories that are not interconnected, such as small island states. As is true for many of the Small Island Developing States (SIDS) worldwide, the energy situation of the Comoros is substantially based on fossil fuel imports. The socioeconomic development of this archipelago is overwhelmingly dependent on energy security from sustainability, availability and affordability perspectives. As a forward-looking response to energy vulnerability, the deployment of renewables to diversify the generation of electricity appears to be an essential prerequisite for guaranteeing a sustainable future. Nevertheless, despite a high potential for renewable energy, only 3.8% of the electricity supply in the Comoros is provided by hydropower. This paper provides a comprehensive overview of the energy situation throughout the Comoros and focuses on renewable energy opportunities to facilitate the supply of green power. This study ultimately shows that renewable energies are rarely exploited despite the powerful potential of different resources. Finally, this paper attempts to provide recommendations for the Comoros to pursue a more sustainable future. • Analysis of the current energy situation of Comoros. • Defining renewable potential and ongoing actions. • Analysis of the specific barriers and policy to the development of RES in the Comoros. [ABSTRACT FROM AUTHOR]

This paper presents an overview of current electricity generation and consumption patterns in the Arctic. Based on published data and new data collection this paper provides an overview of the installed capacity per energy source. A more detailed view of electricity systems is also presented, showing how different types of resources can be used and combined within Arctic communities. The paper briefly discusses which aspects of transmission systems are of special interest under the harsh climatic conditions of the Arctic. A description is given of the various electricity generation technologies that have been proven to be effective for use in Arctic environment, and those that are currently in use, including diesel, hydropower, photovoltaic, and wind power, in addition to discussion of different back-up options. Furthermore, for a more holistic view concerning such energy systems the socio-economic dimension is addressed with a focus on energy security, through an investigation of energy availability and affordability in the Arctic. The availability of energy in the harsh Arctic environments can be crucial for survival and affordability, and can have a huge impact among low-income communities. • Overview of current electricity generation and consumption patterns in the Arctic. • Potential use of different energy resources in the Arctic. • Arctic Energy security. • Socio-economic dimension of energy systems in the Arctic. [ABSTRACT FROM AUTHOR]

Nowadays, millions of people in remote areas do not enjoy an uninterrupted power supply due to the lack of connectivity to the main power grid. Under such circumstances, the only feasible way to access electricity is typically local power generation, often relying on diesel engine–generator sets or photovoltaic arrays. However, on many occasions, this configuration does not fully exploit all available local resources, including biomass. Indeed, most isolated areas have access to local biomass production from agricultural activities, which can be used for local electricity generation through gasification. This paper addresses this challenge by developing an innovative optimal sizing tool for hybrid power plants integrating biomass gasifiers, specifically designed for isolated areas with access to local biomass production. The novel approach models the particular features of biomass gasification technologies, including long on/off times or restrictive ramping limits. To this end, an efficient methodology based on representative weeks is proposed, which is combined with a solution strategy based on the multi-cut Benders' decomposition, thus resulting in a tractable framework that can deal with a huge amount of data efficiently. One of the most salient features of the new proposal is the consideration of local biomass production, which is included in the methodology through an original algorithm. Accordingly, a certain amount of biomass is sourced locally, leading to more accurate and reliable results. The new methodology is applied to a benchmark off-grid community in Ghana. The results demonstrate that the use of gasifiers reduces the project cost notably (by 90%) driven by the reduced biomass cost, which can be supplemented by locally generated biomass from agricultural activities. In addition, this technology constitutes a clean source of energy, reducing the total CO 2 emissions by 83% compared to a baseline case in which only diesel generators are used. Moreover, it is demonstrated that biomass gasification can effectively act as base load power generation technology to reliably cover most of the local demand, thereby enabling a clean and inexpensive dispatchable local power generation. Finally, a sensitivity analysis reveals that the economic feasibility of the plant is more sensitive to the biomass cost than the selling price of biochar, resulting in a 33% increment in the total project cost when the price of biomass increases from 0 to 0.4 $/kg. Nevertheless, gasification remains as the predominant power generation technology even under unfavorable prices. • A novel optimal tool for sizing hybrid plants with biomass gasifiers is developed. • The representative weeks' approach enables efficient data handling. • Multi-cut Benders' strategy is adopted to deal with extended time horizons. • Integrating biomass gasifiers in off-grid communities cuts project costs by over 90%. • Biomass gasification acts as base load power generation to cover most of the local demand. [ABSTRACT FROM AUTHOR]

A universal strategy that integrates PAA grafting, ion exchange, and in-situ chemical reactions to synthesize photothermal materials for enhanced solar-driven interfacial evaporation and gradient materials for electricity generation, respectively. [Display omitted] • A universal strategy is proposed for the preparation of SDIE and FFIPG materials. • Synthesized nanoparticles or nanoplates are evenly spread on SDIE fabric fibers. • A combination of one-way flow and suspension mode is used for fluid evaporation. • All SDIE fabrics achieve excellent evaporation rates at 0.5 cm suspension height. • The fluid flow can constantly generate a potential difference across the FFIPG fabrics. In our contemporary society, addressing the increasingly pressing global resource shortage, particularly the scarcity of vital water resources and energy, is critical for human survival. This paper presents a strategy that integrates PAA grafting, ion exchange, and in-situ chemical reactions to synthesize photothermal materials for enhanced solar-driven interfacial evaporation and gradient materials for electricity generation, respectively. The obtained photothermal material demonstrates exceptional light absorption and photothermal conversion performance. By employing a unique combination of unidirectional flow and suspension mode for water evaporation, remarkable evaporation rates are achieved, with all samples exceeding 2.03 kg m-2h−1. The hybrid mode is also applied to saltwater treatment, where it is found that the evaporation rate is not significantly affected, regardless of the salt concentration. No change in the evaporation rate is observed even after 12 h of continuous treatment with 10 % brine, indicating the robustness and stable performance of the evaporative materials. For the synthesized gradient materials, the flowing fluid can establish a potential difference at both ends of the gradient fabric. The magnitude of open circuit voltage and short circuit current can be controlled by adjusting the measurement distance, the deposited nanoparticles with different polarity and the amount of charge carried. We acquire a maximum output of 209.7 mV using the gradient Cu-S/PAA-cotton fabric, which can be connected in series to power small electronic devices like a digital watch. This research not only advances the design and practical application of high-performance solar evaporators but also illuminates a novel pathway for developing electricity-generating materials. [ABSTRACT FROM AUTHOR]

Several studies calculate the potential of renewable energies throughout the world. However, these studies vary in the underlying assumptions and do not consider several technologies within a uniform methodology, which affects comparability. In this paper, we calculate the worldwide potentials of ground-mounted photovoltaic (PV), concentrated solar power (CSP), and wind onshore and offshore on a 6.5 by 6.5 km grid. The results consist of installable capacity, generated electricity, and specific cost of electricity generation. Our methodology combines high-resolution data for land uses, slope, and hourly weather data with a thorough analysis of different factors for wind power, like hub heights and rotor diameters, and solar power plants, like tilt angle, and temperature-related loss of efficiency. The results show that the summed-up potential capacity of ground-mounted PV surpasses the amount of CSP, wind onshore and offshore combined with 450 TW. Given the cost-potential curve, ground-mounted PV reaches 560,000 TWh at costs below 20 €/MWh, which is twice the projected worldwide primary energy supply of the World Energy Outlook 2022 for the year 2050 with 205,557 TWh. The calculated results can function as input factors for energy system models, which are an important tool to analyse the energy transition. • Model-based global renewable potential calculation. • Calculation of capacity, electricity generation and costs for four technologies. • Results show technical potentials of 662,740 TWh for ground-mounted PV. • Ground-mounted PV shows potentials of 560,000 TWh at costs below 20 €/MWh. • Most cost efficient ground-mounted PV and CSP potentials can be found in Chile. [ABSTRACT FROM AUTHOR]

The rapidly growing of population in the developing countries and their lack of access to electricity, especially in the remote or rural areas, is causing huge challenges for on energy production. Energy is an enabler and a reliable energy supply is critical to sustainable socio-economic development for any nation. Most of Chad's people live in villages with no particular power supply system. Exploiting renewable energies is the only means of fostering development and improving people's welfare. This paper attempts at proposing an energy profile and storage model for Chad in vast remote towns. The paper addresses the key energy gap that is hindering on the development of such systems, it models and assess the potential on electricity generation and using hydrogen as surplus power storage system. A techno-econo-environmental survey on a solar-wind hybrid system in 25 towns in Chad is undertaken using NASA data and HOMER Software. Several hybrid scenarios of energy production and storage is analyzed. The results showed that in the electricity generation scenario, the average total NPC for the studied stations was $ 48164 and the average LCOE was $0.573. The lowest LCOE was related to Aouzou station with 0.507 $/kWh and the highest LCOE was obtained for Bol station with 0.604 $/kWh. In the simultaneous electricity and hydrogen generation scenario, the cheapest hydrogen ($4.695/kg) was produced in the "Grid" scenario, which was the same for all of the stations, with a total NPC of $2413770. The most expensive hydrogen ($4.707/kg) was generated in the "Grid-Wind" scenario and Bol stations with a total NPC of $2420186. The paper develops cost effective models for all hybrid systems combination for both electricity and hydrogen generation across Chad. These findings could help policy makers, investors and other developmental agencies make informed choices on energy access for sustainable development for rural communities in Sub Saharan Africa. • The wind turbine alone was the superior choice at no station in Chad. • The lowest LCOE (0.507 $/kWh) was associated with Aouzou station. • The lowest COH (4.695 $/kg) was associated with Grid scenario. • In electricity generation scenario, Abeche has the lowest emission (63.1 kg/year). • In hydrogen generation scenario, Aouzou has the lowest emission (1109 kg/year). [ABSTRACT FROM AUTHOR]

• Graphical approach to assess matching between photovoltaic electricity and loads. • Combines the conventional measures self-sufficiency and self-consumption. • Possible to visualize improved matching with energy storage and load shifting. • Contribution of photovoltaic electricity for Swedish nearly zero energy buildings. For on-site renewable energy supply, such as photovoltaic (PV) electricity generation, an important issue is the daily and seasonal matching between on-site supply and demand. The matching potential is frequently expressed using the load matching indicators such as self-sufficiency and self-consumption. This paper presents the Energy matching chart, which is a novel graphical approach to visualize the PV-load matching. The chart uses self-sufficiency and self-consumption to provide information regarding the matching in both size and time. Using the Energy matching chart, the matching between PV production and load presented in previous studies is graphically analyzed and compared. Furthermore, the potentials for the two most common measures for improving the matching, namely energy storage and load shifting, are investigated. The results show that energy storage has, on average, a significantly higher potential for increasing the PV-load matching than load shifting. The second part of the paper, illustrates the benefits of the Energy matching chart by evaluating the Swedish implementation of the EU legislation on nearly Zero Energy Buildings (nZEBs). The assessment is performed for detached houses and evaluates the feasibility to use PV and battery systems for Swedish nZEBs. The results show that on-site PV production can help buildings to meet the nZEB regulations, but there are limitations due to the poor time-dependent matching. With a combined PV-battery system, the potential to meet the regulation is significantly larger. To summarize, the Energy matching chart has the potential to become a useful tool in the assessment of PV system and the evaluation of load matching measures. [ABSTRACT FROM AUTHOR]

Accelerating engagement of distributed energy resources unleashed the dependency on traditional electric power generation. To reduce the craving for traditional power dependency and unplanned outages the power distribution sectors are gradually adopting cleaner and reliable electrification. However, the unscheduled and unorganized engagement of stochastic generation from renewable energy sources (RES) makes the distribution system operation more vulnerable. For reliable and continuous power supply with RES , scheduled operation of BSSs and power capacitor (CAP) units can be integrated to provide emergency power supply support to consumers. In this paper, the supply of continuous and reliable power to commercial and emergency customers has been investigated subject to complete reliability (CR). The benefit-to-cost ratio (BCR) has been maximized to give reliable power to consumers by the minimum investment cost by utility, which can benefit both electric customers and power distribution operators in a single platform. The maximization of BCR has been evaluated by optimal S-CDS of the BSSs and S-S of CAP units' operation through the PSO technique in the considered 28-bus active distribution network in different seasons. The techno-economic benefit of integrating only BSSs and BSSs with CAP units in the prospective locations has been analyzed. The improvement in battery life and decrease in SAENS , SADPL , and SADD have been obtained, which shows the efficacy of the proposed work. [ABSTRACT FROM AUTHOR]

In today's China, the reverse distribution of electricity resources and electricity demand makes large-scale and long-distance transmission of electricity inevitable, resulting in the problem of electricity allocation optimization. To address this problem in the region covered by the China Southern Grid (CSG), the paper establishes an optimized model for electricity generation and interprovincial trading strategies in southern China. Based on data from 2015, this paper simultaneously optimizes electricity generation and interprovincial trading strategies in each of the five provinces. The result shows that interprovincial trading in the CSG-served area can yield significant energy, economic, environmental and interconnection benefits. It can reduce the power supply cost and environmental pressure in Guangdong province, help make Yunnan province a hydropower base in China and a thermal power base in southern China, facilitate the completion of the "West-to-East Power Transmission" project, and partly resolve the issues raised in each province's 13th Five-Year Plan as well as the problem of optimizing electricity allocation in the region covered by the CSG. • We propose an annual total optimized model for electricity generation and interprovincial trading in Southern China. • The model optimizes the electricity trading and transmission routes across regions. • The model considers the generation cost and penalty cost of emitting CO 2 , SO 2 and NO x. • Corresponding policies and proposals are put forward for power grid and five regions in South China. [ABSTRACT FROM AUTHOR]

Cameroon has an abundant reserve of energy resources, such as crude oil, natural gas, hydropower, biomass, solar, wind and geothermal energies. However, these resources are still weakly valorised. The country relies mainly on hydropower energy for electricity generation (73%) with persistent power outages throughout the country especially in the dry seasons when water levels are low. Electricity access is about 65–88% in urban areas and around 14% for rural populations. Cameroon has experienced a strong economic growth (growth rate of 5.9% in 2015), accompanied by a rapid increase in electricity demand (1455 MW in 2014). Electricity needs are expected to continue rising over the next decade to reach 5000 MW by 2020 and 6000 MW by 2030. This paper seeks to address energy issues (reliability, accessibility and security) in Cameroon and brings to light the potential and meaningful contributions of renewables in solving energy concern. In order to achieve this objective, an overview, of the energy sector (energy source, access, demand, supply and distribution) is given followed by a review of renewable energy potential, policy, benefits and barriers. In addition, this paper introduces the energy roadmap to achieve a universal access to electricity, which will pave the way for the country emergence by 2035. It is found that energy sector of Cameroon holds promising possibilities of development and diversification given the country's energy potential. With adequate policy, standards, regulations, awareness, capacity building and off-grid renewable energy investments measures, it is possible for Cameroon to meet the future energy targets and ensure meaningful development throughout the country. [ABSTRACT FROM AUTHOR]

The electricity mix in Tunisia mainly relied on conventional energy sources for over 50 years. Recently, due to fossil fuel prices oscillations and national reserves shortage, the need arose for restructuring the energy supply system. Targeting the integration of renewable energies could be a plan for satisfying the increasing demand and the supply independence. However, several macroeconomic conditions and policies present barriers for the integration of Renewable Energy Sources (RES), despite their abundance, availability and environmental benefits. This paper presents a long-term model of Tunisia electricity system, based on OSeMOSYS (Open Source energy MOdelling SYStem), aimed at unveiling potential benefits of increasing RES in electricity production. The paper first investigates peculiarities of Tunisia electricity system, arguing the necessity to include them in the electricity system model. Then, it explains the choice of OSeMOSYS and brought modifications, including peculiar system characteristics. Finally, the model is applied to two scenarios, a Business As Usual case and a 30% RES target in electricity production case, for time horizon 2010–2030. Results demonstrate the importance of system features detailed modelling. Specifically, they show that targeting RES state-invested integration in the electricity mix may allow higher energy independence to be reached, without increasing significantly system costs. [ABSTRACT FROM AUTHOR]

The generation forecast helps to develop the scheduling plan of power sources, build a power balance system and ensure the adequacy of power supply to the power system at the macro level. Therefore, a novel structurally adaptive discrete grey Bernoulli model, called DHGBM(1,1), is proposed in this paper for the prediction of power generation. Firstly, the Hausdorff fractional order cumulative generation operation makes it possible to achieve new information prioritisation. As for the structure of the model, we have extended the nonlinear grey Bernoulli model with the introduction of a nonlinear dynamic structure term, which allows the model to simulate variable generation data and improves the adaptability of the model. In a comparative test of the algorithms, the well-performing differential evolution algorithm was used for hyperparameter optimisation of the model to obtain better predictive performance. Monte Carlo simulations and probability density analysis verified the excellent robustness of the model. In addition, through the simulation tests, we obtained a reasonable range of parameters for the structural terms, thus limiting the complexity of the model, and the phenomenon of model overfitting was effectively prevented. Finally, five actual cases of China's hydro, China's thermal, China's nuclear, China's wind power generation and China's electricity exports are predicted. • A novel nonlinear dynamic structural term is proposed. • A novel structural adaptive discrete grey Bernoulli model is developed. • The robustness analysis of the novel model is established. • Comparative study shows that the novel model is superior to other six models. [ABSTRACT FROM AUTHOR]

• Real case studies of Tazouta and Fez rural area in Morocco. • Hybrid biomass, wind, and solar electricity generation in areas those are rich in renewable energies. • Potential of bioenergy for producing power in rural areas of Fez-Meknes region in Morocco. High dependence of Morocco's energy sector on imported fossil fuels and subsequent associated expensive import bills, as well as global agreements with greenhouse gas emission reduction, has motivated Morocco to utilize renewable energy sources such as hydro, wind, and solar for energy generation. However, in recent years, the use of wind and solar energies in Morocco has accelerated more than hydropower usage because of the reduction in water levels as a result of rainfall drop, global warming, and natural droughts. Morocco has a great potential for electricity generation from solar and wind energies because of many sunny days, vast desert areas, long coastlines, and appropriate wind blow. However, accommodations of wind and solar generating units in electric power systems are difficult because of wind speed variations, solar irradiation uncertainty, and costly energy storage systems. Regarding the huge amounts of biowaste in Morocco, power generation from biomass can resolve this problem and compensate for the decrease in wind and solar energy generation during cloudy, rainy, and/or non-windy moments. Therefore, in the present paper, the capability of hybrid electric energy generation, using biomass, wind, and solar in a Moroccan village of Tazouta and the rural area of Fez city is evaluated. The proposed mixed-integer linear programming model was implemented in A Mathematical Programming Language (AMPL) using a linear solver of CPLEX. The biomass, solar, and wind power plants are biogas units fed by cow manure, 1-kW photovoltaic (PV) modules, and 5.1-kW wind turbines, respectively. The evaluation of the results indicates that hybrid utilization of wind, PV, and biomass energy resources is a more appropriate way for electricity generation in Tazouta and Fez rural areas compared to the individual operation of wind turbines and other combinations of mentioned renewable energy sources. [ABSTRACT FROM AUTHOR]

The centralised power grid bears a heavy burden in a time when consumers expect an uninterrupted reliable power supply, a reduction in carbon emissions, increased efficiency within the national grid and power supplied to remote communities. As expectations increase, it becomes the task of power systems research and design to develop new structures to meet these demands. This has led to alternatives being sought for centralised power generation, which is prone to outages (due to long distance transmission), is a substantial contributor to global carbon emissions, has large transmission losses and is often not a practical solution when supplying remote communities. Distributed generation (DG) looks to remedy these inadequacies by producing power close to its point of consumption, often utilising carbon neutral, renewable energy (RE) sources (sun, wind). To maximise the efficient use of DG, control structures are used to balance the intermittent RE power production with consumer power consumption. One such structure is used to implement control of small scale DG, at a single house/small building level: the nanogrid. This paper explores the current nanogrid research, it collates the existing definitions and uses the knowledge to give a concise definition of a nanogrid. It then discusses the control topologies and techniques which enable the intelligent control of the nanogrid, before presenting the hardware platform used to ensure the efficient operation of a small scale DG system. The paper then considers the interconnection of multiple nanogrids forming a network (microgrid), facilitating the sharing of power between individual nanogrids. The future developments are then explored before the paper's conclusions are presented. [ABSTRACT FROM AUTHOR]

Majority of the power generation in India is carried out by conventional energy sources, coal and fossil fuels being the primary ones, which contribute heavily to greenhouse gas emission and global warming. The Indian power sector is witnessing a revolution as excitement grips the nation about harnessing electricity from various renewable energy sources. Electricity generation from renewable sources is increasingly recognized to play an important role for the achievement of a variety of primary and secondary energy policy goals, such as improved diversity and security of energy supply, reduction of local pollutant and global greenhouse gas emissions, regional and rural development, and exploitation of opportunities for fostering social cohesion, value addition and employment generation at the local and regional level. This focuses the solution of the energy crisis on judicious utilization of abundant the renewable energy resources, such as biomass, solar, wind, geothermal and ocean tidal energy. This paper reviews the renewable energy scenario of India as well as extrapolates the future developments keeping in view the consumption, production and supply of power. Research, development, production and demonstration have been carried out enthusiastically in India to find a feasible solution to the perennial problem of power shortage for the past three decades. India has obtained application of a variety of renewable energy technologies for use in different sectors too. There are ample opportunities with favorable geology and geography with huge customer base and widening gap between demand and supply. Technological advancement, suitable regulatory policies, tax rebates, efficiency improvement in consequence to R&D efforts are the few pathways to energy and environment conservation and it will ensure that these large, clean resource bases are exploited as quickly and cost effectively as possible. This paper gives an overview of the potential renewable energy resources in Indian context while evaluating the present status, the energy demand of the country and forecast consumption and production, with the objective to evaluate and assess whether India can sustain its growth and its society with renewable resources. [ABSTRACT FROM AUTHOR]

If all the resources in power supply side, transmission part, and power demand side are considered together, the optimal expansion scheme from the perspective of the whole system can be achieved. In this paper, generation expansion planning and transmission expansion planning are combined into one model. Moreover, the effects of demand response in reducing peak load are taken into account in the planning model, which can cut back the generation expansion capacity and transmission expansion capacity. Existing approaches to considering demand response for planning tend to overestimate the impacts of demand response on peak load reduction. These approaches usually focus on power reduction at the moment of peak load without considering the situations in which load demand at another moment may unexpectedly become the new peak load due to demand response. These situations are analyzed in this paper. Accordingly, a novel approach to incorporating demand response in a planning model is proposed. A modified unit commitment model with demand response is utilized. The planning model is thereby a bi-level model with interactions between generation-transmission expansion planning and operation simulation to reflect the actual effects of demand response and find the reasonably optimal planning result. [ABSTRACT FROM AUTHOR]

Variability and intermittency are some of the main features that characterize renewable energy sources. Intermittency usually includes both predictable and unpredictable variations. The many drawbacks of intermittency of renewable sources can be overcome by considering some special design considerations. Integrating more than one renewable energy source and including backup sources and storage systems are among the few measures to overcome these drawbacks. These additional design considerations usually increase the overall cost of the renewable system. Furthermore, the presence of more than one energy supply/storage system requires the control of energy flow among the various sources. Therefore, optimizing the size of the components and adopting an energy management strategy (EMS) are essential to decreasing the cost of the system and limiting its negative effects. The energy management strategy is commonly integrated with optimization to ensure the continuity of load supply and to decrease the cost of energy production. Therefore, energy management is a term that collects all the systematic procedures to control and minimize the quantity and the cost of energy used to provide a certain application with its requirements. The energy management strategy usually depends on the type of energy system and its components. Various approaches and techniques have been used to develop a successful energy management strategy. In this paper, a comprehensive review of the approaches proposed and used by authors of many papers is conducted. These approaches include both the standalone hybrid renewable energy systems and the grid-connected hybrid renewable systems. More attention is focused on popularly used techniques to address the features of each system. The selected papers in this review cover the various configurations of the hybrid renewable energy systems for electric power generation only. [ABSTRACT FROM AUTHOR]

Stand-alone micro-grids (MGs) and grid-connected MGs with high penetration level of Distributed Generation (DG) are growing at a fast rate. In these grids, the power quality disturbances such as harmonics, inter-harmonics and deviation from the fundamental frequency are widespread. The influence of these disturbances on two categories of digital metering algorithms is evaluated in this paper. The first category is related to the measurement of the fundamental frequency component of current and voltage signals, which are used as inputs of the digital protection algorithms. Most of the relays only use fundamental frequency component of their input voltage and current signals to fulfill the desired protective functions. The accuracy of the protective relays highly depends on the performance of the applied algorithms for extracting the fundamental components. The second evaluated category is related to the reactive power calculation algorithms, which are used in the static VAr compensator (SVC) control system. Utilizing SVC is growing due to the DGs such as wind turbines magnify voltage fluctuations called flicker. Since the SVC compensates only the reactive power related to the fundamental frequency component, the reactive power signal should not be sensitive to the harmonics. In addition, the reactive power calculation should be fast enough that SVC can follow the abrupt changes to mitigate the flicker, efficiently. In this paper, frequency deviation, harmonic, and inter-harmonic phenomena are considered as the most causes for power quality problems. Their influence in digital metering algorithms is evaluated. It is confirmed that defining new indices is mandatory to fully reflect algorithms׳ accuracy and efficiency. Furthermore, the field measurements of instantaneous voltage and current of a wind farm and electric arc furnaces are used for the evaluation. [ABSTRACT FROM AUTHOR]

• Proposed an original concept called spatial load migration (SLM), which is supposed to fully utilize the space connection between power loads, and provide a new load dispatch approach to address power transmission limitation. • Analyzed the feasibility and constraints of the typical power loads applied on SLM base on a holistic literature review and a utilized assessment architecture, including data center, base station, electric vehicle, mobile storage, and multi-energy equipment. • Provided a brief case study describing the potential of SLM on effective power distribution. • Concluded the power level and accessible appliance of each load type, and discussed the future research direction of SLM. As the transmission capabilities of power systems face challenges from renewable generation and massive electricity usage, power load resources have an increasingly important role in power dispatch. Traditional load dispatch methods are mainly based on the dispatch of load behavior in the time dimension, disregarding the potential of heterogeneous space connections existing in loads, such as communication connections and transportation connections. Although some studies, such as energy hubs or data networks, have utilized some part of space connections, no unified framework has been proposed to distinguish the problems caused by applying space connections or a horizontal review of spatial resources. In this paper, a framework named spatial load migration (SLM), which provides solutions to solving spatial network constraint problems with the enhancement of space connections, is proposed. With respect to SLM, this paper analyzes the mechanisms of typical power load types participating in SLM and qualitative appliance potential. A multi-system-coupled case study is designed with the occasion of power line disconnection. The results show that applying space connections to load dispatch can both expand the controllable objects and increase system performance. [ABSTRACT FROM AUTHOR]

Highlights • Define a global PQ planning problem from both technical and economic perspectives. • Propose an objective function to incorporate both technical and economic aspects. • Develop an optimisation-based global PQ planning approach to mitigate PQ phenomena. • Demonstrate long-term financial benefits of applying proposed mitigation scheme. Abstract This paper presents a comprehensive methodology for techno-economic assessment of power quality (PQ) mitigation solutions, both network-based and device-based, and proposes an optimisation-based PQ mitigation strategy for delivering differentiated PQ in networks integrated with renewable generation. The proposed strategy is based on the evaluation of financial losses due to several critical PQ phenomena, the cost of different mitigation solutions and the payback due to the adoption of particular solution. Furthermore, it accounts for different customers' requirements and provides differentiated levels of PQ across the network. The simulation results present both the financial and technical benefits of the optimal mitigation scheme. [ABSTRACT FROM AUTHOR]

Highlights • Energy exchanges between interconnected utilities has been performed. • Electric energy production is estimated from different fuel sources. • Oligopolistic energy market models with uncertainty/certainty have been proposed. • The power-flow study verifies the quantitative nature of the energy exchange. Abstract An analysis of estimating the electric energy production from different fuel sources and its exchanges between interconnected utilities has been performed, based on the historical trend of economic growth. We used a model that considers meeting the load by committed generators where capacity weighted availability has been factored in for generating units run by same types of fuel. The focus is on Bangladesh, in particular, studying energy exchanges between its different regions as well as potential international energy trading between selected countries in South East Asia (SEA). Another aspect of the paper is to study the utilization of energy resources with less possible negative environmental impacts. Our model also accommodates the effect of gradual/impulsive changes of energy generation and availability of different energy sources. The estimated values match well with the actual energy generation, as reported in Bangladesh power authority's publication. Based on the evaluated expected energy generation, oligopolistic energy market models with uncertainty/certainty have been proposed here to show the probable trading in private sector, and in the mix of private and public sector utilities. Market models also consider the potential cross-border trading. In addition, a power-flow study has been conducted to verify the quantitative nature of energy exchanges between regions. This analysis is intended to facilitate energy system planners and designers with the necessary tools to predict energy distribution in growing electric power systems. [ABSTRACT FROM AUTHOR]

Highlights • India has set a goal to achieve 40% cumulative electric power installed capacity from non-fossil fuel based energy resources by 2030. • Indian bioenergy sector increased by 5.42 times in last 10 years. • Small scale biomass gasification plants, solution for waste biomass disposal. • Energy generation for environment protection. • Reducing air pollution by utilizing crop residue in energy generation. India is an agriculture based economy, and also has a forest cover that comprises roughly 24% of its total geographic area. Thus, an abundance of biomass, in the form of waste material is readily available throughout the country annually. The forest biomass, which consists of deadwood and residues, and the agricultural biomass in the form of crop residues, are presently disposed of by burning, which causes air pollution and damage to the local ecology. This waste biomass can be better used for electricity generation using gasification technology. The total installed capacity for electricity generation in India is 344 GW as of March 2018. Renewable energy makes up 20% of this total, and bioenergy, in turn, makes up 14% of renewable energy. Bioenergy makes up 2.8% of total energy installations in India at present. However, the power being generated through bioenergy sources is about 9.5 GW. In this paper, the most recent statistical data regarding energy generation through bioenergy resources has been presented using currently available sources. Brief descriptions of gasification conversion routes have also been included, with their sustainability conditions, as well as the government policies necessary for implementation in the Indian context. [ABSTRACT FROM AUTHOR]

Abstract Demand response has proven to be a distributed energy resource of great potential over the last decades for electrical systems operation. However, small or medium size facilities generally have a very limited ability to participate in demand response programs. When a facility includes several generation resources, energy storage systems, or even demand flexibility, the decision-making becomes considerably harder because of the amount of variables to be considered. This paper presents a method to facilitate end users' decision-making in demand response participation. The method consists of an algorithm that uses demand and generation forecasts and costs of the available resources. Depending on the energy to be reduced in a program, the algorithm obtains the optimal schedule and facilitates decision making, helping end users to decide when and how to participate. With this method, end users' capability to participate in these programs is clearly increased. In addition, the method is contrasted by simulations based on real programs developed at the Campus de Vera of the Universitat Politècnica de València. The simulations carried out show that the developed method allows end users to take advantage of the potential of their facilities to provide demand response services and obtain the maximum possible benefit. Highlights • A method to facilitate decision-making in demand response is proposed. • The proposed algorithm enables facilities to participate in demand response programs. • The proposed method maximises the benefits that can be obtained with demand response. • A method to optimise demand response participation is tested. • Participation in demand response with distributed energy resources is facilitated. [ABSTRACT FROM AUTHOR]

Abstract During the last two decades, a relevant development of renewable energy sources for electricity generation has been observed in Spain. Their diffusion has provoked deep changes that at times have been controversial. The large penetration of renewables under the recent economic conditions has affected power plants, triggering changes in the regulatory framework. In Spain, the use of Combined Cycles Gas Turbines (CCGTs) for complementing intermittent renewables is meant to ensure the security of supply. This paper aims toward a better understanding of the effects of renewables deployment and the modifications of the regulatory framework in terms of resource and capacity support schemes. Highlights • A relevant development of RES has been observed in the Spanish electricity system. • A substantial loss of generation was detected for Spanish CCGT. • National regulatory framework in the field of electricity changes continuously. • A clear regulatory position should be taken in order to re-order the electricity sector. [ABSTRACT FROM AUTHOR]

Abstract The Brazilian electricity system is an important example of a large country relying on a high renewable energy matrix with a major focus on hydropower, which has historically allowed for low carbon electricity production. However, the increase in the demand and climate change impacts on the availability of these renewable resources represent important challenges for long-term power planning. The contribution of this paper is twofold: Firstly, a first attempt to use the EnergyPLAN model for the analysis of the Brazilian electricity sector and in particular to study future scenarios is presented. Secondly, the possibility of achieving a 100% RES system is also addressed. The 100% RES scenario is found to be theoretically possible but a substantial increase in the overall installed capacity would be required, to support the grid mainly during the spring and summer season. The results underline the importance of seasonal complementarity of hydro and wind power and reveal how an increase in RES would add exportation potential, reducing also the Brazilian external energy dependency. The study identifies risk factors for these high RES scenarios and outlines several avenues for future research to address cost, environmental and technical uncertainties of the system. Highlights • The Brazilian power sector is analysed with EnergyPLAN computer model. • Renewable scenarios are compared for technical, cost, emissions and risk parameters. • The importance of seasonal complementarity of hydro and wind power is outlined. • The 100% RES scenario results in full decarbonization of the system at higher cost. • The 100% RES scenario results in higher exportation and lower importation potential. [ABSTRACT FROM AUTHOR]

Malaysia's framework for energy development was established in the early 1970s. Henceforth, many successive policies were introduced as potential resources for electricity generation and utilization. Currently, as a signatory to the United Nations Framework Convention on Climate Change, Malaysia is sparing a number of effort to comply with the policy to meet the challenges of mitigating over-dependence on fossil fuels, reducing carbon levels, and achieving sustainable national development. This paper reviews the baseline studies on electrical energy policies and the measurement indicators used in Malaysia's electric power system. This research involves a comprehensive survey of electrical energy policies in Malaysia that focus on issues pertaining to energy supply, utilization, its environmental impact and considerations, renewable energy (RE) policies, production and consumption, energy efficiency, and feed-in tariffs. Fourteen energy indicators for sustainable development in Malaysia were investigated through the identification of energy policies in significant areas, such as reliability, safety, adequacy and cost-effectiveness of energy supply; increasing energy efficiency; minimizing environmental impact; and enhancing quality of life in terms of social well-being. The policies and the indicators are classified into different sustainable dimensions and summarized in tables along with the corresponding key references. In this study, future energy planning and options, especially in nuclear and RE programs, as well as the conflict between them, are illustrated through the overall performance relative to targets and benchmarks for past and future projections up to the year 2030. This review seeks to examine the past, present, and future policies and indicators to provide a sufficient overview of Malaysian energy policies for optimizing sustainable development. The goal is for this review to lead to increased efforts to accommodate the increasing demand for the management and utilization of RE, promote energy efficiency, and improve performance in achieving sustainable national development. [ABSTRACT FROM AUTHOR]

Unlike other traditional energy resources, wind power outputs depend on natural wind resources that vary over space and time. Accurate wind power forecasting can reduce the burden of balancing energy equilibrium in electrical power systems. In this paper, we propose the short-term probabilistic forecasting of wind energy resources using the enhanced ensemble method. The enhanced ensemble forecasting methods are grouped into two main categories: temporal ensemble and spatial ensemble forecasting. The temporal ensemble forecasting is implemented by autoregressive integrated moving average with explanatory variable model, polynomial regression with time-series data, and analog ensemble for a probabilistic approach. The spatial ensemble forecasting is implemented by geostatistical model and interpolation with geographical property data. In addition, the stochastic approach, analog ensemble is applied to reduce the uncertainty in wind power forecasting and use of Numerical Weather Prediction models for accurate wind power forecasting is considered. We conduct stochastic wind power forecasting using practical data of Jeju power system and evaluate the system reliability on wind power generation variations. As a result, the proposed model shows better performances than single models, while at the same time providing probabilistic forecasts. Based on these forecasts, the grid operators can identify critical operating time points to prepare for problems that can occur in the system due to wind power variations in advance. [ABSTRACT FROM AUTHOR]

Abstract Three models for the projection of long-term electricity generation for Pakistan are developed in this paper. Baseline (BL), Coal and Renewable Energy (RE) scenarios are used to analyze current and future electricity generation. From an environmental perspective, both the BL and RE scenarios are found to be superior to the Coal scenario, but a cost-benefit analysis indicates that the RE scenario is most expensive though it brings the benefit of effectively reducing dependence on imports of primary fuel. [ABSTRACT FROM AUTHOR]

A transition in the electricity market is required to manage the volatility of increasing renewable energy generation. These fluctuations can be faced with flexible consumption through Demand Side Management (DSM), establishment of further centralized storage capacities and provisioning of dynamic back up generation capacities. At least the latter two options can impose large establishment and operation costs upon the electricity market. Therefore, the feasibility and the resulting potential of coupling the electricity grid with the thermal supply of residential buildings is analysed in this paper. Thereby, inexpensive and widespread thermal storage capacities could be used to improve the integration of dynamic renewable electricity generation. In this paper the technical and economical key impact factors for such thermal DSM approach are elaborated. Based on a literature review, the identified key factors are aggregated to form consistent scenarios of the German “Energiewende” (turnaround in energy policy). The practicability and possible magnitude of the intended DSM is then analysed based on the identified scenarios. All resulting scenarios highlight the growing demand for a flexible electricity market. Especially in scenarios with strong growth of renewable electricity generation, up to 45 GW of flexible electric capacities would be required in Germany by the year 2030. Furthermore, the analysis demonstrates that independently of the energy market development, it is very likely that electricity coupled supply systems will continuously have installed capacities of at least 14 GW. It is found that especially the strong dissemination of smart metering and smart control infrastructure is crucial to incorporate these capacities into DSM activities. Furthermore, the necessity and the resulting benefits of residential end-user participation in the electricity market need to be communicated to all stakeholders to ensure the availability and acceptance of dynamic pricing schemes in the future. [ABSTRACT FROM AUTHOR]

This paper presents a methodological framework using a multi model approach to assess power system security. System security is viewed here as a multidimensional systemic property of the entire energy system. The paper shows that the different dimensions of a secure energy system are correlated, and hence their behaviour cannot be explained solely by an understanding of the individual dimensions or by system elements in isolation. The implication of this is that a proper assessment of the security of a power system requires a combination of different techno-economic models. The paper develops a comprehensive multi-model approach for investigating energy security issues within power systems, and applies it to a case study focussing on the Italian power sector. The core research activity involves using an energy systems model of Italy (MONET) to build a dedicated power systems model (PLEXOS_IT) and then undertaking a soft-linking exercise between the two models. The purpose is to use PLEXOS_IT to investigate the system adequacy of the power system results produced by MONET for future possible energy system scenarios. [ABSTRACT FROM AUTHOR]

Microgrids comprising multiple distributed resources are being increasingly considered for integration into electricity networks. Considering the multiplicity of the distributed resources in a single location and distributed nature of such single entities, it is impractical to represent them as detailed models in power system simulations. Hence, it will be attractive for electricity utilities to employ simplified models of microgrids in dynamic studies. This paper proposes a method for representing grid-tied microgrids as simplified generator or load units in such studies. For this purpose, the paper takes an approach in investigating the applicability of modal analysis as a tool for model equivalencing of grid-tied microgrids with inverter and non-inverter interfaced distributed generators. Validity of the reduced order dynamic equivalents is tested under different operating conditions: power export and import modes, with different load types and fault conditions. Scalability of the model equivalencing approach is demonstrated using a case study developed based on the IEEE 13-Bus test feeder. Furthermore, the model equivalencing is applied on microgrids in a multi-microgrid environment to validate the methodology. The dynamic model equivalent of the microgrid can be represented as a current source at the point of common coupling while retaining all imperative dynamic characteristics. The proposed methodology is also applicable to distribution network clusters comprising distributed generators. [ABSTRACT FROM AUTHOR]

Energy is the basic necessity for life and a key factor to excel a country’s economy. Pakistan despite being richly blessed with natural energy resources is dependent on foreign sources and is currently facing severe energy deficiency. At the time of its independence in 1947, Pakistan inherited 60 MW of power. The energy sector had made some progress in the beginning but unfortunately the growth in positive curve couldn’t last long. The dilemma of the ever increasing gap between demand and supply has rendered Pakistan an energy deficient country where most the people have none or limited access to electricity. This paper gives an overview of the energy status of Pakistan. In this paper, I have discussed (a) major aspects of energy sector of Pakistan—its establishment, history and accomplishments, (b) various institutions for energy generation and distribution, (c) total installed and generation capacity, (d) current energy reserves in the country such as coal, oil, natural gas, nuclear energy, as well as the renewable energy resources which include wind energy, biogas, Hydel energy, geothermal energy, solar energy, tidal and wave energy, (e) current energy crisis in the power sector, discussing the key issues leading to the origin, causes and consequences of the problem. The paper also presents; (f) possible solutions to overcome this crisis which is becoming hazardous for the country’s economy. The various government, semi-government and private organizations and their efforts to resolve the situation of energy deficit and (g) renewable energy can provide an alternative form of energy, why and how it can provide better replacement of other forms of energy, barriers that halt progress in this area and various renewable energy projects have also been illustrated. The goals, principles and impacts of the National Power Policy—2013 is also mentioned in this paper. [ABSTRACT FROM AUTHOR]

Renewable energy sources have a critical role to play in contributing to the diversity, sustainability and security of energy supplies. The main objective of the paper is to gain an understanding of the support mechanism of renewable energy sources most preferred by households in the United Kingdom. This paper analyses households' preferences and willingness to pay under a mandatory scheme where all households contribute compared to a voluntary scheme where only those who wish to pay to support renewables do so (such as the green tariffs offered by electricity suppliers in the UK). Two contingent valuation method (CVM) surveys are used to explore whether the type of payment option has an impact on households' willingness to pay (WTP) for increasing share of renewable energy in electricity generation. The paper also investigates whether the type of payment mode affects respondents' self-reported certainty of paying their stated valuations. The results indicate that the likelihood of paying a positive amount for supporting renewable energy is higher under a mandatory scheme compared to a voluntary payment option in the UK. Respondents have a higher level of certainty in paying their stated WTP under a mandatory payment scheme. [ABSTRACT FROM AUTHOR]

Abstract: Two-thirds of input energy for electricity generation in the USA is lost as heat during conversion processes. Additionally, 12.5% of primary fuel and 20.3% of electricity are employed for space heating, water heating, and refrigeration where low-grade heat could suffice. The potential for harnessing waste heat from power generation and thermal processes to perform such tasks is assessed. By matching power plant outlet streams with applications at corresponding temperature ranges, sufficient waste heat is identified to satisfy all USA space and water heating needs. Sufficient high temperature exhaust from power plants is identified to satisfy 27% of residential air conditioning with thermally activated refrigeration, or all industrial refrigeration and process heating from 100 to 150 °C. Engine coolant and exhaust is sufficient to satisfy all air conditioning and 68% of electrical demands in vehicles. Overall, this study demonstrates the potential to reduce USA primary energy demand by 12% and CO2 emissions by 13% through waste heat recovery. A detailed analysis of thermal energy demand in pulp and paper manufacturing is conducted to demonstrate the methodology for improving the fidelity of this approach. These results can inform infrastructure and development to capture heat that would be lost today, substantially reducing USA energy intensity. [Copyright &y& Elsevier]

This paper analyzes the capability of Reunion Island to achieve electricity autonomy by 2030. Currently, electricity production in Reunion Island is mainly based on imported fuels while it is blessed with high levels of renewable energy potentials. The issue addressed in this paper is the technical and economical feasibility of this ambitious target. The approach relies on a prospective study conducted by the TIMES-Reunion model which provides future production mixes according to different scenarios. It is combined with a quantitative assessment of reliability of power supply with two reliability indicators, regarding that intermittent sources may highly develop and consequently worsen reliability. This study enables us to draw three main conclusions: (i) electricity autonomy can be achieved thanks to high levels of biomass production and of intermittent sources; (ii) however, since fuel oil׳s power plants appear as back-up units, the reliability of power supply will be lowered. This is illustrated by the decrease of the reliability indicators over the time horizon; (iii) however, provided that appropriate rules on the instantaneous production are enforced, a generation mix that both complies with the electricity autonomy target and with a satisfying reliability of power supply is possible. [ABSTRACT FROM AUTHOR]

As an important means of demand-side response, the reasonable formulation of the electricity price mechanism will have an important impact on the balance between the supply and demand of electric power. With the introduction of Chinese intelligence apparatus and the rapid development of smart grids, real-time electricity pricing, as the frontier electricity pricing mechanism in the smart grid, will have great significance on the promotion of energy conservation and the improvement of the total social surplus. From the perspective of system dynamics, this paper studies different real-time electricity pricing mechanisms based on load structure, cost structure and bidding and analyses the situation of user satisfaction and the total social surplus under different pricing mechanisms. Finally, through the comparative analysis of examples under different real-time pricing scenarios, this paper aims to explore and design the future dynamic real-time electricity pricing mechanism in China, predicts the dynamic real-time pricing level and provides a reference for real-time electricity price promotion in the future. [ABSTRACT FROM AUTHOR]

The city of Pécs in Hungary has developed an energy strategy to be implemented in the years to come which proposes structural changes in both the supply and demand sides. This paper offers a model based on the proposed system aimed at providing a basis for comparison for decision-makers. The model has been developed with the help of energy system analysis tool energyPRO, and covers the three basic sectors of heat, electricity and transport. It shows the energy system of Pécs in terms of hourly production and demand levels – and these values enable the model to analyse intermittent energy sources. The model is also validated – to ensure that it is satisfactory for the simulation of future energy systems. It analyses two scenarios – one where the city does not implement the changes proposed in the strategy, and one where it does. The paper compares the two scenarios based on sustainability, energy security and affordability. [ABSTRACT FROM AUTHOR]

Rice husk-based electricity generation and supply has been popularized in South Asia by the Husk Power Systems (HPS) and the Decentralised Energy Systems India (DESI), two enterprises that have successfully provided electricity access using this resource. The purpose of this paper is to analyze the conditions under which a small-scale rural power supply business becomes viable and to explore whether larger plants can be used to electrify a cluster of villages. Based on the financial analysis of alternative supply options considering residential and productive demands for electricity under different scenarios, the paper shows that serving low electricity consuming customers alone leads to part capacity utilization of the electricity generation plant and results in a high cost of supply. Higher electricity use improves the financial viability but such consumption behaviour benefits high consuming customers greatly. The integration of rice mill demand, particularly during the off-peak period, with a predominant residential peak demand system improves the viability and brings the levelised cost of supply down. Finally, larger plants bring down the cost significantly to offer a competitive supply. But the higher investment need and the risks related to monopoly supply of husk from the rice mill, organizational challenges of managing a larger distribution area and the risk of plant failure can adversely affect the investor interest. Moreover, the regulatory uncertainties and the potential for grid extension can hinder business activities in this area. [ABSTRACT FROM AUTHOR]

Burnable off-gases generated in engineering process plants are regularly utilised as energy sources. A common use is for steam production, where excess steam is allocated to power generation turbines. Fluctuating off-gas productions may, however, result in power generation losses from turbine trips, due to insufficient steam. Numerous power co-generation investment models exist, which are typically based on cost minimisations or meeting energy demands. These models do not, however, incorporate plant-specific historic steam profiles and typically use average-based patterns for decision making. This paper presents a novel stochastic mixed integer linear programming model that utilises historic steam profiles to determine optimal turbine investments in terms of the net present value. A further advantage is the ability to investigate the investment and procurement of a, typically very expensive, supplementary energy resource to assist during low off-gas flow periods. The proposed model is solved to optimise over 10 years for an engineering factory seeking to invest into an energy recovery plant. Optimal results demonstrate how natural gas in a fluctuating off-gas environment can increase power generation profits and should be invested in, together with a 30 MW turbine. Furthermore, an average-based approach yields sub-optimal investments and overestimates the net present value beyond 22%. [ABSTRACT FROM AUTHOR]

Bangladesh, currently a low middle-income economy aspires to become a high middle income country by 2021. To achieve such aspiration, the country will have to ensure adequate power supply for its fast growing economy. Bangladesh lacks energy resources for power generation. This paper explores some of the power supply scenarios with special focus on power imports and higher use of renewables. Using the technology rich, least cost optimization model 'The Integrated MARKAL-EFOM System (TIMES)', the authors developed four possible future power supply scenarios for Bangladesh. These scenarios include an energy security framework (based on the Power System Master Plan (PSMP) 2016 report), a high power import scenario, a scenario with higher use of renewables and a combined high power import - high renewables development scenario. The analysis indicates that the present energy security framework ensures energy security with diversifying fuels used for power generation, however, scenarios with high power imports and a high share of renewables (including the combined scenario) bring down the cost of supplying power along with a reduction in expensive fossil fuel imports while maintaining energy security as fuel sources for power generation still remain diversified. [ABSTRACT FROM AUTHOR]

The carbon emission reduction being achieved by Chinese coal combusted electricity generation are critical for global sustainable development and environmental protection. In this paper, to achieve carbon emission reduction and reliable electricity generation, an equilibrium strategy based on a hydro-wind-thermal complementary system under an uncertain environment that fully considers the cooperation of hydro power plants, wind power plants, and coal combusted thermal power plants is proposed as an optimization method. By considering the randomness of seasonal wind speeds, the water flow uncertainty and the fuzziness of coal thermal plant carbon emissions, the complementary model is more scientific and practical than current models. A case study from Bijie City is presented to demonstrate the practicality and efficiency of the optimization model. The results from 12 different wind speed and water flow level scenarios showed that the complementary system provides a superior method to solving the conflicts between carbon emission reduction and reliable electricity generation and therefore could be of great assistance to system operators when scheduling generation. [ABSTRACT FROM AUTHOR]

In the present paper, life cycle analysis of coal-based synthetic natural gas (SNG) is performed for heat supply and electricity generation in China with a full consideration of energy efficiency, environmental pollutions and greenhouse gas emissions. Several different technical routes of SNG are studied in detail and the emissions of SO 2 , NO x , CO 2 and energy efficiency are all calculated. For comparisons, technical routes of ultra supercritical and coal-fired power generations are also analyzed together with a direct use of coal for heat supply. Our results show that the cogeneration of heat and electricity is a suitable technical route for SNG utilization. Comparing with ultra-supercritical and coal-fired power generations, technical routes based on SNG could significantly reduce the emissions of pollutants (especially for heat supply) with an acceptable level of the energy efficiency. After synthesis of SNG, our life cycle analysis suggests that SNG should be transported to the energy demand center for further power generation locally. [ABSTRACT FROM AUTHOR]

Tidal range power plants represent an attractive approach for the large-scale generation of electricity from the marine environment. Even though the tides and by extension the available energy resource are predictable, they are also variable in time. This variability poses a challenge regarding the optimal transient control of power plants. We consider simulation methods which include the main modes of operation of tidal power plants, along with algorithms to regulate the timing of these. This paper proposes a framework where simplified power plant operation models are coupled with gradient-based optimisation techniques to determine the optimal control strategy over multiple tidal cycles. The optimisation results inform coastal ocean simulations that include tidal power plants to gauge whether the benefits of an adaptive operation are preserved once their hydrodynamic impacts are also taken into consideration. The combined operation of two prospective tidal lagoon projects within the Bristol Channel and the Severn Estuary is used as an example to demonstrate the potential benefits of an energy maximisation optimisation approach. For the case studies considered, the inclusion of pumping and an adaptive operation is shown to deliver an overall increase in energy output of 20–40% compared to a conventional two-way uniform operation. The findings also demonstrate that smaller schemes stand to gain more from operational optimisation compared to designs of a larger scale. [ABSTRACT FROM AUTHOR]

This paper proposes the use of Combined Heat and Power systems for providing water and energy, and thermal and electric utilities, in geographically isolated communities, where the interconnection with the grid is not available. A common design practice is to implement different energy storage technologies, usually batteries, for reducing the gap between energy generation and electric consumption. However, in communities with low incomes, it is not possible to use batteries due to the high capital costs. This work presents a new approach for providing simultaneously electricity and water using the fresh water extraction and storage for reducing the gaps between generation and consumption. The proposed approach is based on a mixed integer nonlinear programming formulation, which accounts for the optimal selection of multiple combined heat and power technologies and the sizing of the water storage and pumping technologies. A multi-objective analysis is presented considering as objective functions the economic costs and environmental impact associated with the space used by the system and water consumption. A community in the mountains of Mexico is presented as case study. The results show that it is possible to provide energy and water at low costs and reducing the environmental impact, reaching a trade-off between the considered objective functions. [ABSTRACT FROM AUTHOR]

Distributed energy resources present opportunities to serve grid and customer need through two-way power flow. New values, methods, and planning are required to efficiently interconnect and utilize DERs. This paper analyzes New York’s and California’s DER proceedings to provide a comparison of the similarities and differences between these and other states that will result in different levels of deployments and valuations of DERs. [ABSTRACT FROM AUTHOR]

Thermal absorbers and their integration methods are critical to solar photovoltaic/thermal (PV/T) modules. These two elements directly influence the cooling effort of PV layers and as a result, the related electrical/thermal/overall efficiency. This paper conducts a critical review on the essential thermal absorbers and their integration methods for the currently-available PV modules for the purpose of producing the combined PV/T modules. A brief overview of different PV/T technologies is initially summarized, including aspects of their structure, efficiencies, thermal governing expressions and their applications. Seven different types of thermal absorbers and four corresponding integration methods are subsequently discussed and summarized in terms of their advantages/disadvantages and the associated application for various PV/T modules. Compared to traditional thermal absorbers, such as sheet-and-tube structure, rectangular tunnel with or without fins/grooves and flat-plate tube, these four types, i.e. micro-channel heat pipe array/heat mat, extruded heat exchanger, roll-bond heat exchanger and cotton wick structure, are promising due to the significant enhancement in terms of efficiency, structure, weight, and cost etc. The appropriate or suitable integration method varies in different cases, i.e. the ethylene-vinyl acetate (EVA) based lamination method seems the best option for integration of PV layer with thermal absorber when compared with other conventional methods, such as direct contact, thermal adhesive and mechanical fixing. Finally, suggestions for further research topics are proposed from five aspects. The overall research results would provide useful information for the assistance of further development of solar PV/T modules with high feasibility for widespread application in energy supply even at district or city-level in the near future. [ABSTRACT FROM AUTHOR]

• A two-stage optimization framework is presented for the self-healing operational scheduling. • The capacity withholding process of non-utility distributed energy resources is considered. • The proposed framework reduced the maximum values of the capacity-withholding index by 71%. • The algorithm reduced the expected values of aggregated operational and interruption costs by 88%. This paper presents a multi-stage day-ahead and real-time optimization algorithm for scheduling of system's energy resources in the normal and external shock operational conditions. The main contribution of this paper is that the model considers the non-utility electricity generation facilities capacity withholding opportunities in the optimal scheduling of system resources. The real-time simulation of external shock impacts is another contribution of this paper that the algorithm simulates the sectionalizing of the system into multi-microgrids to increase the resiliency of the system. The optimization process is categorized into two stages that compromise normal and contingent operational conditions. Further, the normal operational scheduling problem is decomposed into three steps. At the first step, the optimal day-ahead scheduling of system resources and the switching of normally opened switches are determined. At the second step, the optimal real-time market scheduling is performed and the switching of normally closed switches is optimized. At the third step, different extreme shock scenarios are simulated in the real-time horizon and the effectiveness of sectionalizing the system into multi-micro grids are assessed. Finally, at the contingent operational conditions, the optimal topology of the system and scheduling of energy resources are determined. The proposed method was successfully assessed for the 33-bus and 123-bus test systems. The algorithm were reduced the expected cost of the worst-case contingencies for the 33-bus and 123-bus systems by about 97.89% and 88.11%, respectively. Further, the average and maximum values of the 123-bus system capacity-withholding index for real-time conditions reduced by about 67.40% and 71.05%, respectively. [ABSTRACT FROM AUTHOR]

Abstract: There is a general consensus that solar power is one of the cleanest energy technologies available. Nevertheless, investment in large-scale Solar Power Generators (SPGs) is largely impeded by the intermittent nature of solar power. Since the electricity market has a critical responsibility to maintain the reliability of energy supply, the SPG can be registered only as the market semi-scheduled generator (AEMC, 2011). This option excludes the advantages of providing baseload supply, which in turn impedes efficient market contracting for SPGs. The existing approach relies on energy storage or co-generation facilities to be built at the same connection point as the SPG to compensate for output shortages when there is insufficient sunlight. The co-located facilities require significant additional investment in infrastructure. This paper proposes a market based financial approach that does not require an additional construction effort. The approach financially links solar or other intermittent power generation with a gas-fired station through a set of tailored swap-type instruments. These swaps (based on solar energy forecasting) are designed to insure and hedge the SPG against a drop in its output. They contractually link physically separated solar and gas generators to form a single entity termed the Virtual Generator (VG). The VG arrangement requires the SPG to provide solar power when possible and the gas generator to kick in when there is any shortfall due to random clouds or at nightfall. Thus the proposed VG will have the capacity to produce reliable baseload supply. The profitability and design of the proposed financial setup for both the solar and gas generator has been tested in this research. The model has been prototyped on real market and solar data, the results demonstrate the benefits of implementation. While the paper is focused on links with gas generators, the developed financial setup is applicable to a broad range of fast-ramping power generators, such as hydro, including pumped-hydro storage as well as electrical batteries and biofuels. [Copyright &y& Elsevier]