DefinePK

Abstract

The depletion of conventional energy sources, the global quest to reduce greenhouse emissions and the exponential increase in fossil fuels are several reasons that there is more focus on hybrid renewable energy systems (HRES). HRES are deployed to, improve energy security, address the increase in energy demand, and mitigate against environmental degradation while reducing greenhouse gas emission to achieve socio-economic development. Power plants are particularly located closer to the load mostly in cities where they are far from rural areas. HRES microgrids provide an alternative to the grid in rural areas where it is inaccessible due to distance and terrain. The volatility of HRES requires an energy storage system for power balancing and provides continuous power flow even during power fluctuation from renewable sources. Energy management strategy is a necessity in such systems for reliability; provide good power quality, and optimal use, of distributed energy sources in the system. This paper hereby proposes an energy management system (EMS) which is a control technique for managing power flow in response to demand, supply, and storage conditions. This hybrid microgrid energy system is composed of a photovoltaic (PV) system, a micro-hydropower (MHP) system, and a Lithium-ion battery storage system to supply a 180kW load. The energy management strategy is designed to maintain the supply to the load by dispatching battery power when there is a drop in irradiance and absorb power when there is access. The system is implemented in accordance with IEC/ISO 62264 using internal control loop and primary control. The system is modelled in a Matlab/Simulink environment with various scenarios and the results obtained show immediate power injection from the battery storage system when there is a drop-in renewable power which helps to maintain power and voltage despite the fluctuation.