Design and Cost Analysis of an Off-grid Solar Grain Mill

Solar Energy in Rwanda is one of renewable energy sources that is being utilized nowadays in different remote regions of the country due to its considerable social-economic impact. The off-grid solar photovoltaic system turns solar irradiance into electricity to be used in remote areas without being connected to the national grid. Normally people living in those areas use diesel engines to perform their daily activities which require electricity and this has a crucial negative effect on the environment as they are contributing much to the environmental pollution. To address this problem and to reduce these effects caused by thermal engines, this project designs a solar system that will replace those thermal engines by not only reducing their environmental effects but also by allowing the households living in vicinity of system location to have easy access to the electricity. An off-grid solar grain mill provides the grain mill services to those people in remote areas far from the national grid. The system designed will use the solar home system components such as photovoltaic modules, charge controller, batteries and an inverter as generation components and grain mill machine. It has the capacity of 13.56kW whereby 7.5kW of them are used to run grain mill machines and the remaining are used by the local community for lighting purposes. Electrical design and simulation were done by using MATLAB SIMULINK for solar systems. The research method includes weather condition, site survey, data collected from different organizations related to agriculture and energy sector. The system designed and simulated via software has shown good characteristics in terms of both performance and running grain mill machines. The overall system provided ways of getting services to people who don’t have access to electricity especially whose daily life is agriculture based. The total cost of the project was estimated to be $29,690 with its annual income of $9,720 and then a payback period of 3.05years.