Feasibility analysis of river off-grid hydrokinetic systems with pumped hydro storage in rural applications

• The option of using hydrokinetic with pumped hydro storage in rural South Africa is examined.
• Techno-economic feasibility is conducted in comparison to the system with battery storage systems.
• The two schemes are compared in terms of cost of energy produced and technical viability.
• Results show that hydrokinetic with pumped hydro is a cost-effective and reliable rural electrification option.

Hydrokinetic power generation is currently gaining interest as a cost effective way of supplying isolated areas where reasonable water resource is available. However the seasonal characteristic of the water resource as well as the intermittent fluctuating load demand prevents this power generation system from being entirely reliable without appropriate energy storage system. Few researchers have recently analyzed the use of hydrokinetic systems as standalone or combined with other energy source, however the authors of these researches did not explore other means of storing energy except for traditional battery storage systems. In this study, the most conventional and established storage technology, pumped hydro storage, is proposed to be used in conjunction with a standalone hydrokinetic system in off-grid power supply. The techno-economic feasibility of such combination is analyzed and compared to the option where batteries are considered as storage system. The operation principle of the system is presented; the mathematical model and simulation model are also developed. Simulations are performed using two different types of loads in rural South Africa as case studies to demonstrate the technical cost advantages as well as the cost effectiveness of the proposed supply option. The results reveal that the novel micro-pumped hydro storage based hydrokinetic system is a cost-effective, reliable and environmentally friendly solution to achieve 100% energy autonomy in remote and isolated communities.