Experimental Testbed and Performance Evaluation for Rooftop Solar PV System and Generator Set

Adoption of renewable energy sources into daily energy consumption has become both trends and necessity worldwide to cultivate environmentally friendly attitude of living. On top of that, Indonesia was once a member of oil exporting countries, but recently the county has been forced to become a net oil importer due to increasing internal demands. So fossil fuel and electricity are getting pricier. The use of rooftop solar photovoltaics system with a backup system such as a generator set (genset) provides a viable alternative solution. Such a solution is quite popular in Indonesia due to their wide availability and abundance of solar radiation. The underlying questions are: how efficient is such approach, and how can the efficiency be improved. In this paper, first the electric power and energy production of an installed rooftop solar photovoltaics system is studied and possible losses in the system are estimated by comparing daily measurements and PVGIS modelled energy productions. The study reveals that the current system is estimated to have 29% loss that is attributable to the inefficiency in the PV panel, cabling and inverter.Tests on the genset were performed to verify the quality of the AC electricity output and to produce the fuel consumption characteristic of the genset. It was achieved by attaching electric loads to the genset output while inputting a fixed amount of gasoline volume, and recording the running time of the genset for each load. Each test was done for a different electric load. Knowing the running time of the genset, total electrical energy output of the genset could be calculated and its energy efficiency could be calculated. The resultant efficiency curve for the genset used in this study yielded a maximum of 15% of usable electric energy out of 100% of supplied fuel energy. It demonstrated the quite big loss in converting fuel energy to electric energy. Genset producing electricity ideally should be loaded high enough of around 80% of its ideal capacity to further minimize losses.These findings from experimental setup are useful to consider and where to focus for the next study to gain improved efficiency when combining multi-sources in the context of renewable energy and smart grid. These findings will be applicable in most parts of the world.