A Highly Practical and Affordable Microgrid Design Project for Developing Rural Communities: Case Study in Ghana

This paper describes a hands-on student-centered summer project in Africa. Through two separate Graduate and Undergraduate Cooperative Education courses, electrical engineering students at a University in North Dakota have the opportunity for participation and exposure to an early practical and professional work experience closely related to their academic focus area. This simultaneous combination of academic and professional work experience has proven to have a tremendous positive impact on students’ learning and enables them to fully develop their professional identity as engineers early before they graduate. At the completion of the courses, students submit a written report and give an oral presentation to a broader audience on details of the work performed and their findings and learning. The experience that students gain through this program directly contributes to the new ABET-EAC Student Outcomes (1) through (7). Using a set of rubrics designed based on the ABET-EAC Students Outcomes and in consultation with the students’ academic advisors and work supervisors, the course instructor issues a final course grade for the participating students. This paper presents the work experience of a participating student at the graduate level in a humanitarian community service program in Africa. Through this program, the student successfully designed and built an electrical power system microgrid for a small and remote community in Ghana. The paper first examines the difference between microgrids and centralized power networks and discusses the suitability of microgrids for providing electric power to rural communities in developing countries. Next, the advantages and disadvantages of employing AC and DC power in microgrids for developing regions are discussed with regards to expected loads, generation sources, transmission/distribution efficiency, stability and control, protection and safety, and reliability and maintenance, with the conclusion that DC microgrids are better suited for developing communities. A practical methodology for selecting optimal distribution conductor sizes is presented. The microgrid design principles developed in the first half of the paper are then applied to an actual case study of Lingbinsi, Ghana, an agricultural community consisting of 267 homes. A step-by-step design approach for the microgrid is presented, resulting in a microgrid design using about 13kW rated capacity of photovoltaic panels and about 40 kWh rated capacity of battery storage with a total lifetime cost of about $133,000. The microgrid supplies 15W of power to each home for five hours per day to provide basic lighting and charging needs and delivers power to a water tower pump that provides enough water for the entire village. The microgrid material, maintenance, and installation costs can be supported by household energy payments that are 17-47% less than current average lighting costs in the region, depending on the financing strategy, while also providing enough power for a water pump. This indicates that the microgrid is highly affordable to the community. This project and its practical engineering experience directly contribute to the new ABET Student Outcomes (1) through (7). Therefore, the project and its outcomes can be adapted to serve as a practical undergraduate senior design project or a case study in renewable energy systems courses.