Power Load Shedding Research Articles

Solar empowerment in agriculture: investigating photovoltaic energy’s impact on efficiency among wheat farmers

Persistent electricity shortages in Pakistan, causing prolonged grid power load shedding, have adversely impacted various sectors, notably agriculture and the livelihoods of rural farmers. Literature suggests that adopting photovoltaic solar energy can mitigate these issues. This research aims to measure the impact of photovoltaic solar energy on the technical efficiency of food productivity in Khyber Pakhtunkhwa, Pakistan, applying data from 580 respondents. Addressing self-selective bias through ESR and stochastic frontier production function model is utilized to assess technical efficiency. The findings of this study reveal that farmers using solar energy experience a significant improvement in technical efficiency, with 15.8 percent of them achieving a 7.643 percent increase, after accounting for self-selection bias. Furthermore, the positive effects are more pronounced among larger farms and those with greater farming experience. This study underscores the importance of evidence-based approaches in implementing solar energy solutions, highlighting their potential to foster sustainability and equitable development at the grassroots level. The research culminates with policy recommendations that underscore the importance of promoting the photovoltaic solar energy use among farmers to improve food security and increase agricultural productivity.

Optimized Battery Capacity Allocation Method for Wind Farms with Dual Operating Conditions

In order to solve the problems of wind power output volatility and wind power participation in frequency regulation, a method for optimizing the capacity allocation of wind farm storage batteries based on the dual grouping strategy and considering the simultaneous execution of the dual conditions of energy storage in fluctuation smoothing and primary frequency regulation is proposed. Firstly, a two-layer model is established to optimize the capacity allocation under dual operating conditions, i.e., the planning layer takes into account the lifetime, cost, and benefit, and the operation layer considers the wind turbine reserve backup and storage control to participate in the primary frequency regulation in a cooperative manner. Then, the dual battery pack operation strategy is embedded with the variational modal decomposition method to determine the charging and discharging operation strategy of energy storage after considering the grid-optimized reference power. An improved particle swarm algorithm with inverse learning pre-optimization combined with variational crossover post-optimization is embedded in the GUROBI computation to obtain the optimal battery storage capacity allocation scheme. Finally, the superiority of the model proposed in this paper in terms of improving energy storage utilization, service life, and economic efficiency as well as reducing wind power load shedding is verified by comparing it with a single execution working condition scenario and traditional battery control strategy.

Chance-Constrained Joint Dispatch of Generation and Wind Curtailment-Load Shedding Schemes With Large-Scale Wind Power Integration

Wind curtailment (WC) and load shedding (LS) are indispensable measures to mitigate the operational risk in high-renewable power systems. Moreover, WC and LS schemes should be pre-scheduled and confirmed by related entities to make them applicable. In this paper, we propose a novel chance-constrained economic dispatch (CCED) model which can generate optimal WC and LS schemes accounting for the reserve shortage and transmission congestion problems. In the proposed method, WC and LS power are formulated as random decision variables, with which the infeasibility issues of conventional CCED are fully addressed. To solve the proposed model, we first convert the complicated chance constraints into a set of deterministic inequalities equivalently by employing the conditional Value-at-Risk (CVaR) representation and duality theory. Then, a two-layer iterative algorithm is proposed to solve the equivalent problem efficiently, which is based on the generalized Benders decomposition (GBD) framework. Numerical tests demonstrate the effectiveness and efficiency of the proposed method.

Exposure levels of radiofrequency electromagnetic fields from mobile base stations in Mpumalanga province, South Africa

This study assessed the radiofrequency electromagnetic fields (RF-EMF) exposure levels proximal to primary school structures in the Mpumalanga province of South Africa. A calibrated Acoustimeter was used to measure the RF EMF levels at defined distance points of 50 and 100m away from the three mobile base stations, that provide a 4G network coverage. All the measurements were obtained from three mobile stations, each from one district municipality, using 30 minutes intervals for repeated measurements. The measured peak exposure level at 50m was 887 μW/m2 and 905 μW/m2 at 100m. No statistical difference was found when comparing the measurement data obtained at 50 and 100m from the three district municipalities. However, comparison of measurements obtained at 50 and 100m for all base stations were statistically significant, p-value< .002 and p< .003 respectively. The measured RF EMF exposure levels at both distance points were below the reference levels found under International Commission for Non-ionizing Radiation Protection (ICNIRP) RF guidelines. It is therefore essential for mobile base station companies to consider proximity of residential structures when installing new base stations in the future, and regularly maintain the components of mobile base towers, especially in the current state of power load shedding in South Africa.

A Solar Photovoltaic Performance and Financial Modeling Solution for Grid-Connected Homes in Zambia

Zambia is today 90% hydropower dependent, but this may change because Zambia and the World at large are today facing a changing climate that affects the ecosystem, rain patterns, and spurs drought which reduces the production of hydropower. The current power deficit experienced in Zambia points to a need to deploy a renewable energy generation-mix strategy. This study conducts a solar photovoltaic performance and financial analysis for grid-connected homes in Zambia to investigate the role of solar energy as an enabler for energy security in Zambia using the National Renewable Energy Laboratory (NREL) System Advisor Model (SAM) simulation method. It further reviews the available solar irradiance, modeling a detailed grid-connected photovoltaic system using locally available products for a single owner in a power purchase agreement (PPA) with the Zambia Electricity Company Limited (ZESCO). This model would alleviate the current power load shedding experienced by the residential sector, of up to 22 hours of no electricity out of 24 hours in a day. Alongside the technical performance model and an unfavorable business climate in Zambia, a financial model is also developed to help assess project feasibility and financial viability. A 1 kW solar PV system was modeled at an installation cost of US$1.27 per watt on a short-term basis of 5 years and found that the project is feasible with a 28.52% IRR achieved in 3 years and a 69% performance ratio and a debt service coverage ratio (DSCR) of 5.12 by the end of the project life, thereby indicating capability to turn around Zambia’s energy poverty to meet the UN SDG 7.

Effects of Climate Change induced electricity load shedding on small holder agricultural enterprises in Zambia: The case of Five Southern Province Districts

Zambia is currently facing electricity shortages, which affect the power supply throughout the country. Load shedding and power outages have had effects on agricultural subsectors, industries and household food security with negative implications for the productivity of the country‘s economy. This paper analyses the effects of climate change induced electricity power load shedding on smallholder farmers‘ agricultural productivity and production in Mazabuka, Monze, Choma, Kalomo and Namwala districts of Southern Province of Zambia for the 12 months period starting February 2015 through to February 2016 . To gather the information needed to understand the effects and extent of load shedding and also determine whether there were differential outcomes on various enterprises, 149 structured sets of questionnaires were administered at enterprise level comprising of Dairy, Abattoir (beef), Crop irrigation, Feedlot and Poultry. Furthermore, to broaden and deepen the understanding of the effects and extent of load shedding on smallholder farmers, 17 focus group discussions were conducted with a total of 203 farmers from the same studied enterprises. Although ZESCO had released load shedding time tables for each district and for each different feeder, the study reveals that some enterprises in sample area were apparently either not aware of the scheduled power cuts or ZESCO had failed to follow their programmed load shedding time table. The findings show that Monze and Namwala respectively started experiencing power cuts as early as February 2015 and March, 2015, and were the top two districts having abrupt power cuts. Many enterprises experienced reduction in the estimated average level of production during load shedding. The production level reduced by 26.6% for cattle slaughtered in abattoirs, 19.3% for steers raised for market in feedlots, 13.5% for chickens raised for market in poultry and 34.7% for quantity of milk produced in dairy (milk collection centers). On the contrary, the quantity of irrigated crop harvested increased by 18.6% during load shedding. The effects and extent of load shedding was profound in the extra costs incurred to sustain operations of the enterprise. More than half (64.71%) of Non sole proprietors (compared to Sole proprietorship (45.26%) agree to incur more costs due to power cuts. Further, there were delivery delays from suppliers (46.3%) and to customers (46.3%) due to load shedding. As they try to adapt and mitigate the effects of load shedding on the operation of the enterprise, majority of Sole proprietorship (49.47%) and 46.15% of Non-Sole proprietorship often times reduce the expansion of the enterprise. It is also significant that stocking and use of charcoal/firewood during load shedding was often used by Sole proprietorship (61.7%) compared to 26.92% of Non-Sole proprietorship. Similarly the majority Sole proprietorship (85.26%) and Non-Sole proprietorship ( 75%) resorted to renting alternative tools/equipment to back up power during load shedding, while the highest proportion of Non-Sole proprietorship (69.23%) often resort to buying alternative tools/equipments to back up power supply. Of the assets bought/rented in as alternative power sources, charcoal/breezier became very common among the poultry enterprise while generators were common among dairy, abattoir and feedlot.

Reactive Power Aspects in Reliability Assessment of Power Systems

Reactive power plays a significant role in power system operation. However, in reliability evaluation, attention has seldom been paid to reactive power. In conventional power system reliability evaluations, the fixed maximum and minimum values are applied as the reactive power limits of generators. Failures of reactive power sources are rarely considered. The detailed causes of network violations for a contingency are also seldom studied. Real power load shedding is usually used to alleviate network violations without considering the role of reactive power. There are no corresponding reliability indices defined to represent the reactive power shortage in the existing techniques. Reactive power shortage and the associated voltage violations due to the failures of reactive power sources are considered in this paper. New reliability indices are proposed to represent the effect of reactive power shortage on system reliability. The reliability indices due to reactive power shortages have been defined and are separated with those due to real power shortages. Reactive power limits determined by real power output of a generator using P-Q curve have been studied. A reactive power injection technique is proposed to determine possible reactive power shortage and location. The IEEE 30-bus system has been modified and analyzed to illustrate the proposed technique. The results provide system planners and operators very important information for real and reactive power management.