Institute for Development Studies, University of Nairobi

The need to increase the area of agriculturally productive land in Kenya and the fact that large-scale irrigation has been an expensive option for doing so has led planners to explore alternative means of providing water for the smallholder agricultural sector. It is generally believed that small-scale or micro-irrigation schemes hold some potential in this respect, but the costs and problems of using conventional pumping technologies sometimes make these approaches prohibitive. This study reviews the potential uses of wind and solar energy-based water pumping technologies for small-scale irrigation in Kenya. These technologies are dependent on the availability of an adequate wind regime or solar radiation and on the smallholder's access to ground or surface water resources. Financially, they are often characterized by high first costs and by low recurrent costs. Major constraints to the use of windmills and photovoltaic-powered pumps in Kenya are identified in this study, and possible policy options to affect their use are explored. Windmills and solar pumps appear to be financially competitive with and technically comparable (or superior) to diesel pumping technologies under certain conditions of operating load arid insulation or wind regime. This is particularly true for low-head applications and where diesel is costly or unavailable. The major constraint to their use is their high capital cost, even though in the long run they may be cheaper to operate than conventional pumping technologies. It is unclear, however, whether or not small-scale pumped irrigation schemes can be cost effective, regardless of the pumping technology that is used.