Optimization of excess energy storage from an islanding micro-hydropower system as an alternative to dump loads

Abstract Energy needs in many parts of the developed world is characterized by high increase in recent years. This is due to the population growth and industrial development which require a substantial amount of energy sources. But studies have shown a different trend for many developing countries especially in Africa where energy needs is increasing steadily and mostly in the urban areas due to the availability of national grid while in the rural and off-grid areas energy demand is supplied with the local available energy resources and technologies eg. solar energy, wind energy, hydropower or biomass energy technologies as well as hybrid energy systems. In the current research study, a water resource in a form of a small river is available in the rural and off-grid villages of the northern Tanzania. So, in this case a microhydro turbine system have been designed and developed to supply the required electrical power to the off-grid villages. The design configuration of the micro-hydro turbine systems consists of a 75 kW hydro turbine system that will supply a load demand of 1,114.38 kWh/day. But studies from the daily energy supply and demand analysis shows a power surplus of 50 kW (at night time) and power deficit of 30 kW (at evening time) from the MHP system. In this scenario the energy storage option have been considered and based on the analysis, hydrogen energy storage has been considered. This new energy storage approach has been proven to increase the energy storage capacity by eliminating 68.37% of the excess energy needed for the dump load and increasing the excess energy storage from 31.63% for the previous battery system to 100% for the hydrogen system.