• Energy Research

Abstract Reaching universal access to electricity by 2030 requires a massive deployment of mini-grids in rural areas of developing countries. Among the many challenges hindering this process, there are the high uncertainties in assessing demand patterns in rural communities, the costs of field survey campaigns, and the absence of ample and reliable datasets coming from existing projects. This paper tries to address these issues by presenting and discussing a database of load profiles from sixty-one off-grid mini-grids from developing countries worldwide, gathered from the literature, private developers and fieldworks, and reported with technical, socio-economic and geographical characterization factors. A clustering procedure led to the identification of five archetypal load profile clusters, which are presented and analyzed together with their load duration curves. Subsequently, the distribution among the clusters of the various characterization factors selected is studied. The proposed approach allows to widen the range of load profiles usually considered, and to seek correlations between the load profile shapes, the peak power and average energy consumption per connection, the number of customers, the age of measurement, geographical position, operator model, type of tariff and generation technologies present. This work establishes a first step in the creation of a shared database for load profiles of rural mini-grids, helping to overcome the lack of available data and difficulties of demand assessment, proposing original insights for researchers to understand load patterns, and contributing to reduce risks and uncertainties for mini-grid developers.

This paper presents criteria for the optimal operation of an EV charging station, capable of providing the grid with regulation services such as frequency and voltage control, peak shaving, and load leveling. The presence of an additional storage device connected to the charging station is investigated; both configurations are analyzed in which the storage device of each vehicle contributes to such services and in which the charging profile is independently imposed by the vehicle charging control system.

Rural electrification in remote areas of developing countries has several challenges which hinder energy access to the population. For instance, the extension of the national grid to provide electricity in these areas is largely not viable. The Kenyan Government has put a target to achieve universal energy access by the year 2020. To realize this objective, the focus of the program is being shifted to establishing off-grid power stations in rural areas. Among rural areas to be electrified is Habaswein, which is a settlement in Kenya’s northeastern region without connection to the national power grid, and where Kenya Power installed a stand-alone hybrid mini-grid. Based on field observations, power generation data analysis, evaluation of the potential energy resources and simulations, this research intends to evaluate the performance of the Habaswein mini-grid and optimize the existing hybrid generation system to enhance its reliability and reduce the operation costs. The result will be a suggestion of how Kenyan rural areas could be sustainably electrified by using renewable energy based off-grid power stations. It will contribute to bridge the current research gap in this area, and it will be a vital tool to researchers, implementers and the policy makers in energy sector.

Artículos en revistas The governments of developing countries struggle to guarantee the universal access to electricity on their territory and 1.2 billion people are still without any service, especially in remote areas. Hybrid mini-grids can be an effective solution since they exploit local renewable resources integrated with energy storage devices, reduce the use of fuel generators, and defer the construction of long and expensive grids until the growth of demand makes it profitable. Off-grid mini-grids are typically operated with simple load-following dispatching strategies, but predictive approaches can provide better performances, although at the expense of additional computational requirements. This paper investigates the benefits of using rolling-horizon dispatching strategies during the mini-grid design stage, also comparing how the optimal size of components is affected by several technical and economical parameters. Moreover, we propose the use of a stochastic sizing procedure that captures the uncertainties related to the load, to the renewable generation, and to the time required for the fuel procurement and delivery. A case study with real load data collected from an existing mini-grid placed in Habaswein, Kenya, is presented and discussed. The optimal sizing of some components turns out to be almost unaffected by the operational strategies, so their preliminary design can be simplified to avoid time-consuming simulations. Conversely, the optimal sizing of the diesel generator and of its fuel tank is strongly related to both the local economic parameters and the operational strategy of the mini-grid, which must be properly simulated. info:eu-repo/semantics/publishedVersion

Governments are promoting energy community (EC) policies to encourage joint investment and the operation of shared energy assets by citizens, industries, and public authorities, with the aim of promoting economic, social, and environmental benefits. However, ECs require appropriate planning and energy management strategies, which require data that are rarely clean and well-structured. Data providers rarely adhere to a common format for data sharing, which hinders the development of ECs. As the number of ECs is expected to grow significantly, this poses significant issues for stakeholders to quickly and efficiently develop projects. To address this issue, in this paper we propose a literature-based analysis and classification to derive the major data needs for EC planning, as well as a template format for data sharing. Our literature review on ECs successfully identifies the main data required to properly describe this system and its components. Their classification further clarifies that data structures shall account for tabular-like data of various types and flexible dimentionality, or cardinality. A public release of an open dataset for a case study in Pisa, Italy is also provided, supported by realistic or real data for testing the sizing and operation of ECs. The results suggest that data standard practices are needed, and this paper can lay the foundation for their standardization for ECs to fast-forward their deployment as support policy and technical decision-making.

Degradation mechanism of batteries has to be carefully studied when considering their utilization in electrical power systems. This paper presents the results of an extensive experimental campaign, through which three different lithium–iron–phosphate (LFP) cells were subjected to different electrical cycling stresses. The purpose of the campaign was to evaluate the cells’ aging, as well as to try to find parameters on the cell behavior before its end of life, able to act as state-of-life (SOL) (or aging) indicators. The considered stress consists of the cyclic repetition of fixed-duration discharge steps, followed by full charge phases. The three cells under study were subjected to the very same stress pattern but with three different discharge and charge power levels: low, medium, and high. The results showed that the end-of-discharge voltage and the cell internal resistance can be used as good SOL indicators. However, both are significant functions of the cell conditions, such as the state of charge (SOC) and the cell temperature.

Abstract The paper presents the successful field application of active shielding of the magnetic field of HV overhead lines. Two plants have been deployed and are being operated since some years on a 132-kV and a 400-kV line. The solutions adopted minimize the impact on the line structure. Also the configuration of the control systems has been studied in order to avoid any impact on the normal operation of the line. Two different solutions were used; the first is based on a current sensor and a radio transmitter–receiver system, the second relies on the mutual effect between the line and the shield wires thus not requiring any device installed on the power conductors. Both systems have been continuously operated for some years and have assured to keep the magnetic field at the sensitive targets below the desired limits.

Reducing costs and risks to foster rural electrification in developing countries is one of the major hurdles for researchers, firms and practitioners aiming to develop business with rural minigrids, which are local networks that supply energy demand by exploiting local sources. Predictive rolling-horizon operating strategies have proven to reduce operating costs and better cope with uncertainties in renewable sources and demand than standard priority-list approaches, when forecasts are accurate enough. Their main drawback is the need for more powerful controlling devices, which, however, is becoming acceptable for modern operation purposes. Yet, calculating the optimal design of the minigrid operated with predictive strategies can easily require much larger computational requirements than with priority-list rules. In the present paper, we describe a two-stage procedure to reduce the computational requirements of design methodologies based on predictive strategies. First, an optimization is developed using a priority-list strategy, namely load-following, whose results are used to refine the second-stage optimization based on an advanced rolling-horizon strategy. Results suggest significant reduction in computational requirements, up to 84% with respect to standard predictive approaches, with negligible reduction in the optimality of results.

The Italian demo of the H2020 Osmose project, which stands for Optimal System-Mix Of flexibility Solutions for European electricity, is led by Terna and aims at developing a novel Energy Management System (EMS), which allows managing distributed Renewable Energy Sources (RES) and severe grid congestions. This is obtained by properly coordinating innovative flexibility resources which include Dynamic Thermal Rating (DTR) and Demand Side Response (DSR). The DTR methods proposed under this framework have been developed by Ensiel, a consortium of Italian universities active in power systems research. These solutions include a sensor-based method, based on a self-organizing sensor network composed by cooperative smart nodes deployed along the line route, and a weather-based technique, based on a thermo-mechanical model of the monitored line. The main features of these advanced solutions are described in this paper, and the first experimental results obtained on real case studies are presented and discussed in order to prove their effectiveness.