Abstract
This paper reviews works involving small axial flow hydrokinetic turbines specifically for generating electrical power for off-grid remote communities and suggests improvements to overcome a major problem. Turbines mounted on pontoons or suspended using pivot arms from river banks or from jetties are reported able to produce about 1 kW to 2 kW of electrical power suitable for remote homes. However several deployments have experienced major problems with debris attaching to the turbines, resulting in interrupted operation. Excessive work in removing debris and furling result in frequent power cuts, a disadvantage in systems supplying AC power on demand, and this problem impedes the acceptance of hydrokinetic turbines in remote community electrification. Some methods of dealing with the debris problem have been suggested but these all involve interrupted operation. A system using a rotor with swept-back blades is suggested, where debris is shed automatically without lifting the turbine out of water. A deflecting device could also be used to push floating logs away from the swept area. By making the system resistant to debris, efficient axial flow turbines could be used practically in tropical rivers. Accessibility to power enables the use of basic home appliances and to encourage small village industries which can help to improve their socio-economic standard.