How effective are heuristic solutions for electricity planning in developing countries

Acknowledgement The first author would like to acknowledge the University of Aberdeen and the Henderson Economics Research Fund for funding his PhD studies in the period 2011-2014 which formed the basis for the research presented in this paper. The first author would also like to acknowledge the Macaulay Development Trust which funds his postdoctoral fellowship with The James Hutton Institute, Aberdeen, Scotland. The authors thank two anonymous referees for valuable comments and suggestions on earlier versions of this paper. All usual caveats applyPeer reviewedPostprin

A community electrification project: combination of microgrids and household systems fed by wind, PV or micro-hydro energies according to micro-scale resource evaluation and social constraints

When electrifying isolated rural communities, usually standardized solutions have been implemented using the same technology at all the points. However these solutions are not always appropriate to the community and its population. This article aims to describe the technical design of the electrification system of the community of Alto Peru (in the region of Cajamarca, Peru), where the adequate technology was used at each area according to micro-scale resource evaluation and the socioeconomic requirements of the population. Specifically four technologies were implemented: wind microgrids in highlands, a micro-hydro power plant in the presence of a waterfall, a PV microgrid in a group of points sheltered from the wind and individual PV systems in scattered points with low wind potential. This project brought electricity to 58 households, a health center, a school, a church, two restaurants and two shops.Peer ReviewedPostprint (author’s final draft

Renewable microgrid projects for autonomous small-scale electrification in Andean countries

Nowadays, 84% of the world population without access to electricity is located in rural areas of developing countries. In particular, in the Andean countries, about 10.4 million people lack of access to electricity, mainly in isolated poor regions. Considering the relevance of electricity in overcoming poverty and promoting socioeconomic development, local-regional-national governments, supported by international organizations, are making efforts to achieve full rural electrification. In this regard, renewable microgrid projects are an effective alternative where the national grid extension has limitations. The literature on the design of such projects is significant. However, when evaluating experiences, most works focus on an analysis of projects’ performance from a technical and/or economical point of view. In contrast, very few literature has been reported on the comparison of such experiences from the perspective of the design process itself and how decisions are taken by project developers. In this article, five rural electrification experiences in Andean Countries (Bolivia, Ecuador, Peru and Venezuela) are reviewed, analyzing the decisions taken across the design process and showing the suitability of these technologies to extend access to electricity. In the target projects, first, a preliminary analysis is carried out to estimate the energy resources and demand. Next, the system is designed and implemented to meet the demand using the available resources. The five projects illustrate different options for the electrical generation (single, hybrid or combination of technologies), storage (battery or diesel backup) and distribution (microgrid or individual systems), as well as different methods for data gathering and systems design. In addition, a comparison of projects’ real behavior is carried out and their technical performance in terms of energy production and suitability of the technologies implemented is analyzed. These projects can be a good reference for the dissemination of such technologies in future projects in the Andean countries and abroad.Postprint (author's final draft

Including management and security of supply constraints for designing stand-alone electrification systems in developing countries

Hybrid wind-photovoltaic stand-alone systems have proven to be suitable to electrify isolated communities autonomously. Moreover, the use of a combination of microgrids and individual systems has been demonstrated to be very adequate. There are a few tools to assist their design but they only consider economical and technical characteristics. However, the management of the system and the security of supply, both at a community level, are key aspects to design appropriate electrification systems for end-users, thus ensuring projects' long-term sustainability, especially in rural areas of developing countries. In this context, this paper develops a mathematical model to optimise the design of wind-photovoltaic projects combining microgrids and individual systems, and including the aforesaid key issues as constraints. Thus, the aim is to minimise the cost while meeting the technical but also the management and the security of supply constraints. Finally a validation is carried out in the real community of Alto Peru (Peru), proving that the two studied aspects allow obtaining electrification solutions with some benefits that strongly compensate the obtained slight cost increases.Peer ReviewedPostprint (author’s final draft

Off-grid community electrification projects based on wind and solar energies: A case study in Nicaragua

Despite various institutional efforts, about 22% of the total Nicaraguan population still do not have access to electricity. Due to the dispersed nature of many rural inhabitants, off-grid electrification systems that use renewable energy sources are a reliable and sustainable option to provide electricity to isolated communities. In this study, the design of an off-grid electrification project based on hybrid wind-photovoltaic systems in a rural community of Nicaragua is developed. Firstly the analysis of the location, energy and power demands of all users of the community is carried out. A detailed resource assessment is then developed by means of historical data, in-situ wind measurements and a specific micro-scale wind flow model. An optimization algorithm is utilized to support the design defining generation (number, type and location of generators, controllers, batteries and inverters) and distribution (electric networks) systems considering the detail of resource variations. The algorithm is modified in order to consider a long-term perspective and a sensitivity analysis is carried out considering different operation and maintenance costs' scenarios. The proposed design configuration combines solar home systems, solar based microgrids and wind based microgrids in order to connect concentrated groups of users taking advantage of best wind resource areas. (C) 2015 Elsevier Ltd. All rights reserved.Postprint (author's final draft

Experiences of Community Wind Electrification Projects in Bolivia: Evaluation and Improvements for Future Projects

Postprint (published version

Electromechanical modelling and control of a micro-wind generation system for isolated low power DC micro grids

This paper describes the modelling and control of a micro-wind generation system, based on an axial flux permanent magnet synchronous generator (PMSG), for isolated low power DC micro grids. The system consists of a micro-wind turbine including a furling tail, a PMSG, a three phase diode rectifier and a buck converter connected to a battery bank and a load. Furthermore, it incorporates a control system to extract the maximum power output from the wind turbine using the minimum possible number of sensors. The system is simulated in Matlab/Simulink to analyze the dynamical response and it is compared with the current IT-PE-100.Postprint (published version

MILP-based heuristics for the design of rural community electrification projects

Wind-photovoltaic systems are a suitable option to provide electricity to isolated communities autonomously. To design these systems, there are recent mathematical models that solve the location and type of each of the electrification components and the design of the possible distribution microgrids. When the amount of demand points to electrify increases, solving the mathematical model requires a computational time that becomes infeasible in practice. To speed up the solving process, three heuristic methods based on mixed integer linear programming (MILP) are presented in this paper: Relax and Fix heuristics, heuristics based on a Corridor Method and Increasing Radius heuristics. In all algorithms first a relaxed MILP is solved to obtain a base solution and then it is used as a starting point to find a feasible solution by searching in a reduced search space. For each type of heuristic several options to relax and to reduce the solution space are developed and tested. Extensive computational experiments based on real projects are carried out and results show that the best heuristic vary according to the size of instances.Postprint (author's final draft

Optimizing PV microgrid isolated electrification projects—A case study in Ecuador

Access to electricity for the rural and indigenous population of Ecuador’s Amazon Region (RAE) is considered a critical issue by the national authorities. The RAE is an isolated zone with communities scattered throughout the rainforest, where the expansion of the national grid is not a viable option. Therefore, autonomous electrification systems based on solar energy constitute an important solution, allowing the development of indigenous populations. This work proposes a tool for the design of stand-alone rural electrification systems based on photovoltaic technologies, including both microgrid or individual supply configurations. This tool is formulated as a Mixed Integer Linear Programming model including economic, technical and social aspects. This approach is used to design electrification systems (equipment location and sizing, microgrid configurations) in three real communities of the RAE. The results highlight the benefits of the developed tool and provide guidelines regarding RAE’s electrification.Peer ReviewedPostprint (published version