It is usually uneconomic to provide mains power to small remote communities even when high voltage lines pass by a village. Local authorities normally resort to diesel-powered generators which require expensive fuel which is difficult to bring into remote areas. Furthermore they are noisy and require frequent maintenance which is often neglected in remote areas due to limited resources and know-how. Neither wind nor sun provides reliable power in humid tropical regions where there is a lot of still and overcast weather. Towers are found to attract lightning strikes which can destroy electronic controls, fungus grows on solar panels, and the multiple electrical connections on photovoltaic arrays corrode away in hot, humid climates. Micro hydro is an attractive option in mountainous areas, and a 30kW high head and a 3kW low head plant have been built, using village labour and surplus and discarded materials. Both are operating satisfactorily. However conventional micro hydro is not possible in flat country where there is little elevation, and work is now in progress to evaluate suitable hydrokinetic turbines on rivers in the humid tropics. Numerous companies around the world are now developing hydrokinetic turbines to harvest tidal and river flows, but a major problem with most designs is clogging by floating debris, especially in tropical rivers.