Savonius hydrokinetic turbines for a sustainable river-based energy extraction: A review of the technology and potential applications in Malaysia

•A review on the vertical axis Savonius hydrokinetic turbine systems to extract energy from river streams in remote areas is presented.•Significant parameters and improvements on turbine power performance based on previous studies are quantified and discussed.•Gaps and challenges are highlighted and recommendations are proposed in terms of the technical, environmental and socio-economic aspects of the technology. The increasing need for access to reliable off-grid electricity in remote areas, coupled with the negative effects of diesel-based generators, is driving demand for renewable and sustainable energy productions. River-based hydrokinetic turbines are one such environmentally friendly technology that has received growing interest for further scientific studies and real engineering applications within the last decade. Several challenges remain which have hindered the realization of this technology in those areas. This review article focuses on the vertical-axis Savonius hydrokinetic turbines, which are primarily preferred for being simple, practical, and economical for low-load applications in low-income communities in remote areas. The principles, technicalities, and recent improvements of these turbines are comprehensively reviewed and discussed. The potential advantages of implementing such a technology in Malaysia are abundant, primarily due to its monsoon climate with ample precipitation and vast river networks. However, several challenges and gaps still remain, which are identified in this article to further improve the technology for realistic implementation.