Surplus Generation Research Articles

The sufficiency-based, the de-growth, and the official – Critical remarks of the electricity chapter of the Hungarian national energy and climate plan based on a comparison to alternative scenarios

Hungary relies heavily on fossil and nuclear fuel imports from Russia. An urgent challenge is to develop a more sustainable and more independent energy system. There is a 2019 and a 2023 (draft) version of the National Energy and Climate Plan (NECP) but they arguably do not follow this direction. However, there are also alternative scenarios for Hungary that propose more comprehensive changes. This paper compares the targets proposed by the Hungarian NECPs to those proposed in two alternative studies: the sufficiency-based European-focused CLEVER (Collaborative Low Energy Vision for the European Region) scenario (created by a research team including 26 partner organisations from 20 European countries), and the de-growth-based “This Way Ahead” (TWA) scenario (which is the result of a Hungarian inter-university research, coordinated by the ELTE University's energy geography research group). A new element of this recent study is the simulation of hourly electricity supply and demand in these scenarios using EnergyPLAN to compare import requirements, potential surplus generation, and self-sufficiency. The review shows that the NECPs need to be reconsidered to increase the share of decentralized renewable electricity supply in a way that allows progress without increasing energy use and environmental burdens. Priority must be given to the rapid expansion of wind energy capacity by at least 10–20 times, which should be complemented by biogas-based flexible energy supply.

Glimpse on Spot and Derivative Market of Electricity and Nepal’s Hydropower

Energy plays a vital role in a country’s economic development. Nepal abundantly blessed with various renewable resources like hydropower, solar energy, biogas, and biomass can achieve prosperity both economically and socially. Further, with a significant opportunities for the regional electricity market as the country has been surrounded by big powerhouses like China and India. It has huge possibilities for regional trading of renewable energy. The present total Installed capacity of power is 3157 MW in Nepal. With 95% hydropower generation, the energy mix in the Integrated Nepal Power System makes the country a surplus of electricity during the wet season when the water in the river is very high and a shortage during the dry season when the discharge in the river is minimal. Hence, to address the surplus generation during the wet season and shortage of power during the dry season, trading in the region plays a very vital role in balancing the demand and supply of the country. Nepal has been importing power during the dry season power deficit in the market during the dry season when the demand is high leaving NEA at risk of interrupting the supply to its customers. Likewise, uncertainty about clearing a bid during the wet season when the power production is high and Nepal is in the position to export the power in the regional market, as the Hydropower plant has to compete with the cheap coal power plant resulting in financial loss and uncertainty of return on investment. Hence, to tackle the mentioned financial risks, the Electricity Derivative market can be one of the best options as derivatives markets can be used to hedge against price fluctuations in electricity spot markets. Similarly, the uncertainty of power sale can be avoided by selling or buying the electricity through a derivative market for the future time period that secures the price and the amount that can be sold in the market in the future. In a nutshell, the Electricity Derivative market can be a useful mechanism for the development of hydropower in Nepal in the future.

A data-driven distributionally robust expansion planning model for ADNs with multi-microgrids considering energy trading strategy based on game theory

With the increasing integration of distributed energy resources, demand response, microgrids, and automation technologies in modern distribution networks, a market framework for local energy trading among microgrids and the distribution utility is a reality. However, the expansion planning problem for active distribution networks (ADNs) with multiple microgrids is complex due to uncertainties associated with distributed generation and competitive scenarios. This paper proposes a novel data-driven distributionally robust model that considers energy trading and uncertainties in generation and load to solve the expansion planning problem for ADNs with multiple microgrids. The uncertainties are represented using data bins and their probabilities, and the energy trading strategy is modeled based on game theory. The proposed model enables the distribution system operator (DSO) to find the best expansion planning from their perspective, while each microgrid seeks its own benefits. We exemplify the proposed model using a modified version of the IEEE 123-bus test system. Results demonstrate the effects of surplus generation levels on the energy price strategy and the influence of competitive environments on the expansion planning decision. The proposed model provides a new approach to address the complexities associated with the expansion planning problem for ADNs with multiple microgrids and could have significant implications for the design and operation of future power systems.

Status, Problems and Challenges of Kaduna South L.G.A Nigeria on the Solid Waste Management in Unguwan Sanusi

The rapid increase of people, booming budget, rapid urbanization, increase in marketable, agricultural and industrial events are the major reasons for the increase in generation of solid surplus. This paper will inspect the domestic waste management in Unguwan Sanusi, Kaduna South L.G.A Nigeria with the precise objectives which are, to identify the types of domestic waste produced, to identify the approaches of domestic surplus dumping in the study area, and to identify the challenges faced by the inhabitants resulting from waste. According to the findings of the field study, domestic waste management in Unguwan Sanusi area of Nigeria is the responsibility of both the government and private organizations because it affects both parties in some manner. The lack of adequate dumpsites provided by the relevant agencies appears to have an impact on domestic waste disposal techniques in the research area. The analysis was done and presented using, method of questionnaire where in 250 questionnaires were placed and 150 people responded. The data revealed that the respondents had a diverse range of socioeconomic characteristics. It also revealed that locals were dissatisfied with trash management procedures, with many of them being unaware of the body/agency in charge of waste management. For proper hardsurplus management, environmental teaching courses should be introduced in all levels in schools in Nigeria and an additional formal disposal site must also be provided which must be close to one another.

Predictive Energy Management of a Building-Integrated Microgrid: A Case Study

The efficient integration of distributed energy resources (DERs) in buildings is a challenge that can be addressed through the deployment of multienergy microgrids (MGs). In this context, the Interreg SUDOE project IMPROVEMENT was launched at the end of the year 2019 with the aim of developing efficient solutions allowing public buildings with critical loads to be turned into net-zero-energy buildings (nZEBs). The work presented in this paper deals with the development of a predictive energy management system (PEMS) for the management of thermal resources and users’ thermal comfort in public buildings. Optimization-based/optimization-free model predictive control (MPC) algorithms are presented and validated in simulations using data collected in a public building equipped with a multienergy MG. Models of the thermal MG components were developed. The strategy currently used in the building relies on proportional–integral–derivative (PID) and rule-based (RB) controllers. The interconnection between the thermal part and the electrical part of the building-integrated MG is managed by taking advantage of the solar photovoltaic (PV) power generation surplus. The optimization-based MPC EMS has the best performance but is rather computationally expensive. The optimization-free MPC EMS is slightly less efficient but has a significantly reduced computational cost, making it the best solution for in situ implementation.

Stochastic scheduling of energy sharing in reconfigurable multi-microgrid systems in the presence of vehicle-to-grid technology

On the one hand, the inherent intermittency in demands and renewable energy sources (RES) frequently bring challenges such as overload or surplus generation within microgrids. On the other hand, electric vehicle aggregations (EVAs) have garnered substantial attention as a pivotal strategy to address climate change and serve as a sustainable substitute for petroleum-based vehicles. However, the uncoordinated deployment of EVAs within microgrids, especially in the face of the intermittent nature of RES, poses a potential threat to the secure operation of microgrid systems. To tackle the mentioned issues, this research concentrates on interconnecting a group of scattered microgrids to create a multi-microgrid system. In more detail, by developing an energy management strategy to reconfigure the interconnections among microgrids, the efficient exchange of power among these multi-microgrid systems is facilitated, addressing the variability in load demands amidst the stochastic generation patterns of RESs. Besides, grid-to-vehicle (G2V) and vehicle-to-grid (V2G) concepts of EVAs are synchronized within the reconfigurable microgrid structure to enhance the flexibility of the model. To evaluate the model under realistic situations, a scenario-based method is also employed to reflect the effects of uncertainties on the model. The proposed approach, characterized by its mathematical convexity, allows for employing efficient solvers like CPLEX, ensuring the attainment of a feasible global solution within a finite timeframe. The effectiveness of the proposed method is demonstrated through its implementation on a modified 33-bus test system operated as multi-microgrid system. The results show the effectiveness of the proposed approach as a promising tool for optimizing the operation of reconfigurable multi-microgrid systems in the presence of EVAs, leading to operational cost reduction and voltage profile enhancement.

Why germanys energiewende may fail to meet its goals: insights from power system simulation with natural generation

In order to achieve the Paris climate targets, the German government has developed phased plans and anchored these in an amendment to the Renewable Energy Sources Act (EEG). This not only defines expansion targets for renewable energy producers, but also the additional amounts of energy that must be available in the electricity grid in future if it is to supply the mobility and building heating sectors, which are currently still powered by fossil fuels. While the lack of grid transport capacities is recognized and discussed in the public debate, another known and critical hurdle is rarely presented here. This is the temporal distribution of power from renewable energies and its effects on the processes involved in controlling the grid balance. By analyzing a target scenario specified in the EEG for 2030 and another for 2040+, which a German economic research institute recommends to policymakers, the aim is to investigate whether their targets can be achieved under the conditions of the natural fluctuations occurring in Germany and the quantities of renewable energy that can be harvested with a reasonable use of resources. The focus is on simulating future generation curves using historical data in such a way that they show the typical weather-driven behaviour to be expected in Germany. Unavoidable Surplus generation is used as efficiently as possible with electricity and hydrogen storage systems. Both scenarios fall considerably short of their targets. CO2-free coverage of the demand specified for the long-term future is only possible with a quantity of generators that is at the limit of what is feasible. The reason for this is that the current plans are obviously based on an unrealistic picture of the temporal distribution of renewable energy output. Achieving the transformation goals in Germany could be much more complex than politicians currently believe and may require a change in strategy sooner or later.

ECONOMIC FOUNDATIONS IN ANTIQUITY: A HISTORICAL EXPLORATION OF ANCIENT EGYPT

This exhaustive investigation thoroughly explores the complex economic history of ancient Egypt, providing insights into key components such as agriculture, trade, and inflation. The study illuminates the significant roles played by the state system in molding the economic landscape of this ancient civilization. The economic structure of ancient Egypt demonstrated a profound interdependence with its imperial dynastic structure and advanced technological capabilities. Agriculture, serving as the foundational element, prospered through the annual Nile inundation, yielding crucial surpluses essential for trade and taxation. Trade, predominantly conducted through barter, played a substantial role in the economic framework, with documented instances of both state-controlled and private enterprises. A central focus of the article entails a thorough exploration of the widespread social and economic ramifications resulting from inflation, particularly the noteworthy Ptolemaic copper inflation. This nuanced analysis significantly contributes to a deeper comprehension of the intricacies inherent in the economic history of ancient Egypt. Precisely, the article conscientiously recognizes the significance of surplus generation and the assessment of labor value. It underscores the pivotal roles undertaken by both g

Optimal generation expansion planning model for solar PV generation on Run of River-based hydro-based power system using binary genetic algorithm

Abstract This paper presents a binary genetic algorithm approach developed to solve the optimal generation expansion planning problem for solar photo-voltaic (PV) based Run of River (ROR) hydro generation systems. The results show that the methodology effectively solves mixed-integer, constrained nonlinear generation expansion problems. The model is then used to optimize the generation expansion problem for the electricity grid in the eastern region of Nepal, considering the under construction and planned solar PV and ROR-based hydropower plants. The optimal problem is formulated to determine the optimal number, location and type of power plant to fulfill the demand for the electricity grid of the eastern zone grid of Nepal. Results show that the total generation from the optimal sites combining hydro and solar sites is found to be about 26% of that of total energy in the Nepalese grid. However, the total demand in the system under consideration for the year is about 1352 GWh. With eliminating line losses, a surplus generation of about 1377 GWh has been found. This surplus can be used as power pooling with neighboring countries. The system has a surplus during the wet season but needs to be improved during the dry season. Hence, appropriate policies can be formulated for power banking and pooling to balance the demand–supply in the system.

Análisis técnico y económico del sistema de producción de <i>Theobroma cacao </i>L. en el sur del departamento de Córdoba, Colombia

The southern zone of the department of Córdoba Colombia, for more than two decades has been promoting the cultivation of cocoa as a productive alternative in the replacement of illicit crops. There is no evidence of a study documenting the technical and economic characterization of the cocoa production system. The objective of this work was to analyze the production system from a technical and economic point of view. The sample is made up of 158 farmers selected at random. The information included aspects related to this production system in the municipalities of Montelíbano, Puerto Libertador, Tierralta and Valencia. The economic returns were obtained by the technique of the concession with producers with experience. The producers with an average age of 57 years of which 77% are male and 23% are women, about the educational level, basic primary predominates with 54% and 20% not having access to any level of schooling. The production model is that of family farming, average yields are 570 k/ha-1. The average income per year is 5,687,500 $/ha-1 the costs are 5,041,015 COP. per hectare which allows the generation of surpluses. The internal rate of return is 36% higher than the capital opportunity cost. It is concluded that with the local technology the costs are recovered, and generate surpluses for the producer of 1658,984 COP per hectare per year.

Generic optimal power flow for active distribution networks

Active distribution networks (ADN) may operate in different modes according to the generation demand balance and the capacity of the primary grid for imposing a constant frequency. Conventionally, a customized optimization model is used for each operating mode. Unlike that conventional approach, this article proposes a general optimization model capable of operating the system in three different modes: grid-connected, islanded with a surplus of generation, and islanded with a deficit of generation. Real-time operation is required in this framework with guarantees such as global optimum, uniqueness of the solution, and fast algorithm convergence; for this reason, a convex approach is employed for grid modeling. Numerical experiments demonstrate that the proposed optimization-based operation model can handle the three types of operation while ensuring the safety operation with frequency and voltage within expected limits.

Hydropower station scheduling with ship arrival prediction and energy storage

Effectiveness improvement in power generation and navigation for grid-connected hydropower stations have emerged as a significant concern due to the challenges such as discrepancies between declared and actual ship arrival times, as well as unstable power generation. To address these issues, this paper proposes a multi-objective real-time scheduling model. The proposed model incorporates energy storage and ship arrival prediction. An energy storage mechanism is introduced to stabilize power generation by charging the power storage equipment during surplus generation and discharging it during periods of insufficient generation at the hydropower stations. To facilitate the scheduling with the eneragy storage mechanism, the arrival time of ships to the stations are predicted. We use the maximization of generation minus grid load demand and the maximization of navigability assurance rate as two objective functions in the scheduling process. The model uses the Non-Dominated Sorting Beluga Whale Optimization (NSBWO) algorithm to optimize and solve the real-time discharge flow scheduling of the hydropower stations in different time periods. The NSBWO algorithm combines the Elitist Non-Dominated Sorting Genetic Algorithm (NSGA-II) and the Beluga Whale Optimization (BWO). The experimental results show that the proposed method has advantages in predicting the expected arrival time of ships and scheduling the discharge flow. The prediction using XGBoost model reaches accuracy with more than 0.9, and the discharged flow obtained from scheduling meets the demand of hydropower stations grid load while also improves the navigation benefits. This study provides theoretical analysis with its practical applications in a real hyropower station as a case study for solving hydropower scheduling problems.

The Prediction of IVF Outcomes with Autologous Oocytes and the Optimal MII Oocyte/Embryo Number for Live Birth at Advanced Maternal Age.

Background and Objectives: Delayed childbearing in advanced age might be associated with a low prognosis for achieving pregnancy. Therefore, it is important to establish a predictive tool that will optimize the likelihood of a live birth at advanced age. Material and Methods: The retrospective study was conducted at the Ferona Fertility Clinic in Novi Sad (Republic of Serbia), between January 2020 and May 2021. The survey included 491 women aged ≥35 who met the inclusion criteria and who were subjected to an IVF (in vitro fertilization) treatment cycle. Results: The average number of retrieved oocytes, MII (metaphase II) oocytes, and developed embryos significantly decreased in advanced age. Age was also found to have a significant adverse effect on pregnancy and live birth rates. In women aged ≥35, 10/12 MII oocytes or 10/11 embryos are required for reaching an optimal live birth rate/cumulative live birth rate. Optimal CLBR (cumulative live birth rate) per one oocyte was achieved when 9 MII oocyte were retrieved. Conclusions: The study indicates that the cut-off for increased risk is ≥42 year. However, despite low live birth rates, autologous IVF for these women is not futile. An increase in the number of retrieved mature oocytes and a generation of surplus cryopreserved embryos could reinforce LBR (live birth rate) and CLBR. Clinicians should be very cautious in counseling, as autologous IVF may only be applicable to women with good ovarian reserve.

Wind generator and storage system scheduling for customer benefit and battery life

Due to increased fossil fuel use and fossil fuel limitations, the Indian energy industry is migrating to non-conventional energy resources such as solar power, wind production, and fuel cells, among others. The unpredictability of non-conventional energy sources makes it difficult to balance an electrical system when they are incorporated, necessitating the incorporation of a storage device into the grid. In a microgrid system with wind turbine generation (WTG) and a battery energy storage system (BESS), the BESS may reserve energy during periods of surplus generation and release it to the grid during times of peak demand. The suggested technique establishes the state of charge (SOC) schedule for the BESS by employing an artificial rabbit optimisation (ARO) algorithm that minimises energy costs for customers. The state of health (SOH) of the energy storage is incorporated as an ageing coefficient, which causes the BESS to behave conservatively in order to retain its lifespan. Using a time of use (TOU) tariff, simulation results suggest a substantial possibility to boost the savings of consumers in a grid-connected micro-grid. The simulation findings indicate that by efficiently scheduling the BESS power management technique, the proposed method improves a number of distribution system efficacy.

Local Economy as the Key Driver of Urbanization in the Indian Sundarbans

The relationship between local economic development and urbanization is a vital policy concern across the world, especially in the developing countries. The local economy exhibits enormous potential in the process of transformation of a rural area into an urban one. Based on the theoretical discourse of planetary and subaltern urbanization, this article explores the role of the local economy, even in the form of banal activities, in the process of urbanization of the Indian Sundarbans, a highly vulnerable part of the Ganga–Brahmaputra delta. For this study, we have relied on two facets of local economy—that of the local market centres, and the household economy of small towns. In the local market analysis, we have analysed market details such as the growth story of entrepreneurs, the function of shops in providing services and in developing their own profit level for sustenance and further growth. Household economy has been analysed from the perspective of changes in the occupational structure, nature of employment and household income in order to understand the surplus generation and reinvestment of the same as the local capital. This article is based on an intensive field survey that used the stratified random sampling method. A total number of 240 households and 100 shops have been surveyed from four towns. Both quantitative and qualitative methods of data collection have been followed. The article argues that the local economy plays a key role in the urbanization process of the Indian Sundarbans, as the regional economy is gradually shifting from the farm to non-farm activities.

Quantification and economic assessment of surplus bread in Italian small-scale bakeries: An explorative study

The generation of bread waste at suppliers and retailers is often linked to the production of surplus bread. This study reports the results of the first direct quantification and economic assessment of surplus bread conducted in Italy, involving a panel of 12 bakeries and their branches located in the Lazio region, which compiled a daily diary for 5 months. They are small-scale bakeries which reflect the typical structure of the Italian businesses in the bakery sector, producing fresh bread and selling it directly to consumers. The surplus bread measured during the study consists of 6,694 kg in total, with an average quantity of 4.83 kg/day per bakery. Studying the three main products (common bread, focaccia bread and bread rolls), the average rate of surplus is respectively 5.88 %, 3.99 % and 5.28 % of the production. The corresponding economic loss represents, on average, 5.44 % of the daily turnover. A set of factors seems to exert highest influence on the generation of surplus, as the range of production, location and number of customers. When surplus bread occurs, in 63 % of the cases it is managed on alternative routes to avoid disposal. Even if detected surplus bread does not necessarily become waste, it indeed represents a big loss for bakeries.

An Energy Management Approach for Isolated Power System using Low Load Diesel

Renewable energy sources (RES) are well known sources for providing energy in distant regions. This is the reason that hybrid isolated power system (HIPS) is utilized which integrates solar energy and wind energy. Renewable energy (RE) relies on environmental conditions. The technologies such as batteries or diesel generator (DG) need to be employed to meet the load demand. Battery energy storage system (BESS) can diminish the limitation but this can add expense and intricacy to the system. DG is an excellent choice to meet load demand but it has certain limitations. Due to diesel load set point, excess RE generation is consumed via regulating devices such as dump load or BESS. As a result, systems designed for high RE penetration are now more complex, expensive, and wasteful. This study analyses low load diesel (LLD). It is a method for minimizing surplus generation hence decreasing system intricacy. It also reduces fuel utilization without causing the control architecture to become overly complicated hence reducing the need for BESS. It provides an alternate method for redefining diesel generation's low load capacity. This work provides an economic analysis of LLD including comparisons to traditional BESS applications. This analysis shows low operational cost of the system including LLD than BESS. Hence demonstrating that BESS can be replaced with LLD. The use of LLD also lowers fuel usage. A power system model of HIPS is simulated using MATLAB/Simulink.

The effect of pretreatment choice on cellulosic ethanol production from sugarcane straw: An insight into environmental impact profile and GHG emissions mitigation potential in Brazil

The exploration of residual lignocellulosic biomass for biofuel production is crucial to achieve significant greenhouse gas (GHG) emissions mitigation within the following decades, translating to diminished agricultural environmental impact and land-use change dynamics. On the other hand, cellulosic ethanol production pathways are typically resource-intensive, in energy and chemical terms, which directly influence its carbon intensity. Pretreatment choice, to this end, is key, since it dictates the overall process performance and yield, and may include crucial flows, under the life-cycle perspective, such as solvents and other chemicals. This work, then, aims to evaluate the effect of pretreatment choice, namely hydrothermal (HT), steam explosion (SE), and alkaline (AK), in the technical and environmental performance of cellulosic ethanol production from sugarcane straw (SCS), extending this analysis to the final GHG emissions mitigation potential for gasoline and fossil-generated electricity substitution, under the Brazilian context in São Paulo. Results show that, while AK provided the highest ethanol yield, this pretreatment option gave the lowest electricity generation surplus, and its sodium hydroxide usage was identified as an important environmental hotspot in most impact categories, which narrowed down its GHG emission mitigation gap for gasoline substitution. HT and SE presented similar ethanol and electricity yields, with SE being the most balanced option in terms of productivity and environmental impact profile. By selecting the SE route, all of the available SCS in São Paulo could be converted into 10% of the Brazilian annual ethanol production, and mitigate 5.4 MtCO2e of gasoline emissions, 15% of the Brazilian Biofuel Policy (RenovaBio) target for 2022.

"Москітна флотилія" на енергетичному фронті: малі енергетичні мережі на базі цифрових платформ

In the conditions of Russia's military aggression, the role and importance of measures aimed at ensuring the energy security of the state is growing. The introduction of digital technologies has a significant potential for improving management mechanisms, increasing the reliability and efficiency of both individual components and the country's energy system as a whole. A special place in this process is occupied by the deployment and integration of the sector of local networks of renewable energy generation into the country’s energy system, which are created on the basis of digital platforms. The purpose of the proposed work is to define the potential of digital platforms as a means to coordinate the interaction between private generators of renewable energy in local energy markets. The research tools include structural, functional, systemic and institutional analysis. It is shown that the development of microgrids of renewable energy generation based on digital platforms is able to stimulate radical restructuring of the production system and electricity distribution markets. The author reveals various peculiarities of digital platforms as an organizational form of interaction in local energy markets. It is shown that they provide a synergistic effect of uniting small producers of renewable energy into a microgrid and forming a two-sector model of the public energy system. The structure of microgrid digital platforms is presented. They unite the owners of personal rooftop solar photovoltaic systems, wind, bio-, and hydropower units, power generation surplus storage stations, consumers, and energy distribution companies on the basis of the core platform. The article reveals the mechanism of building energy systems based on the principles of "Industry 4.0". Attention is focused on the need to implement a comprehensive policy to support the platformization of the renewable energy sector. The tools for its provision are presented.

Differentiation tracing identifies hematopoietic regeneration from multipotent progenitors but not stem cells

Hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs) generate the immune system in development, and contribute to its maintenance under steady-state conditions. How stem and progenitor cells respond to increased demand for mature cells upon injury is a fundamental question of stem cell biology. Several studies of murine hematopoiesis have reported increased proliferation of HSCs in situ when exposed to inflammatory stimuli, which has been taken as a proxy for increased HSC differentiation. Such surplus generation of HSC may fuel enhanced HSC differentiation or, alternatively, maintain HSC cellularity in the face of increased cell death without enhanced HSC differentiation. This key question calls for direct measurements of HSC differentiation in their natural niches in vivo. Here, we review work that quantifies native HSC differentiation by fate mapping and mathematical inference. Recent differentiation tracing studies show that HSC do not increase their differentiation rate upon a wide range of challenges, including systemic bacterial infection (sepsis), blood loss, and transient or persistent ablation of specific mature immune cells. By contrast, MPPs differentiate more rapidly in response to systemic infection to accelerate the production of myeloid cells. These new in vivo data identify MPPs as a major source of hematopoietic regeneration; HSCs might not contribute to regeneration while remaining protected.