An islanded renewable energy microgrid emulator for geothermal, biogas, photovoltaic and lead acid battery storage

An islanded renewable energy microgrid emulator for geothermal, biogas, photovoltaic and lead acid battery storage controlled by a two level control system is presented. The control system consist of a primary level voltage-reactive power and frequency-active power and a secondary level energy management algorithm based on the balance between the power produced by the renewable energy generators, state of charge of the battery bank and the loads. The management control strategy is to cycle charge the batteries at a reference value in order to use efficient the available resources. The primary resource is considered the geothermal energy and the most cost effective the photovoltaic energy. A buffer zone is kept in the battery bank in order to store energy produced by the photovoltaic system as much as possible. The presented microgrid used to test the energy management strategies uses emulators for the geothermal and biogas generators but the results can be scaled for a higher power microgrid.