REVIEW OF THE DESIGNS OF THE MAIN TECHNOLOGIES FOR MICRO-HYDROELECTRIC GENERATION

Abstract

Mini-hydro, one of the main renewable alternatives of the current energy system, has decreased its production percentage in recent years due to different environmental considerations. However, this technology can be applied to microgeneration ranges, avoiding several of these drawbacks and taking advantage of sites where several kilowatts of hydraulic power are currently wasted, or where it is simply not feasible to keep them connected to the power grid. The problem lies in the greater difficulty in achieving a balance between the energy generated and the costs involved in these facilities, due to their low efficiency when traditional machines work far from the operating points for which they were designed and, therefore, to their lower production. In the present study, a bibliographic review has been carried out, gathering some modifications made to large traditional turbines to adapt their operation and efficiencies to lower flow rate and head ranges, having achieved values higher than 80 % only with geometric variations and/or by modifying the number of blades, among others. Furthermore, the analysis of several technologies developed expressly for these operating points has also been included, which will therefore work at their optimum points when working in microgeneration. It can be seen that in both cases the studies are still very varied and do not have a common pattern, so there is still a long way off in terms of research that will help to channel this technology. Key words: microturbines, hydropower, efficiency, new technologies, renewable energy.