Design and Construction of a Small-Scale Vertical Axis Wind Turbine for Off-Grid Lighting in Northern Bauchi State

Many rural settlements in the North East hinterland of Bauchi State lack grid electricity connection and are located in areas with moderate annual average wind speeds that could support small wind energy systems. This study presents the design, construction, and performance testing of a small-scale Savonius-type vertical axis wind turbine intended for off-grid lighting in a rural household in Alkaleri local government area. The turbine was designed for a rated output of 50 watts at a wind speed of 5 metres per second, consistent with the local wind resource assessment conducted using data from a portable anemometer deployed over four months. Rotor dimensions, blade geometry, and shaft bearing specifications were determined through aerodynamic and structural calculations. The rotor and tower were fabricated using sheet metal blades, mild steel shaft, and a welded tubular tower, with a permanent magnet generator salvaged from a bicycle dynamo system. Performance tests were conducted in the field at measured wind speeds between 3 and 8 metres per second, with output voltage and current measured using a digital multimeter and clamp meter. The turbine generated usable electrical output at wind speeds above 3.2 metres per second and achieved a maximum output of 47 watts at 6.5 metres per second. The system powered two 9-watt LED bulbs and a mobile phone charger during testing. Keywords: Savonius turbine, vertical axis wind turbine, off-grid energy, rural electrification, Bauchi State.