Abstract:
Hybrid power systems consist of at least two energy sources deployed to serve a common load. Renewable energy resources are largely dependent on weather and/or time of day and this gives them the disadvantage of low availability, unreliability, instability and high cost of energy. Hybrid Power Systems are designed to address individual weaknesses of deployed energy resources. In this study, design and optimization of wind-solar and grid hybrid power system was done in order to determine its viability in meeting a specific load of a commercial consumer in Kenya. East African School of Aviation (EASA) was selected as a case study because it is a midsized learning institution with diverse and reasonably high energy demand typical of a commercial consumer. It did therefore provide a suitable case study for developing a viable hybrid power system for similar energy consumers. This research was thus focused on designing an optimized Wind-Solar PV-Solar Thermal and Grid power system to meet local energy demand of EASA in Nairobi Kenya. This objective was met by carrying out site energy demand assessment, resource assessment, power system components selection and simulation using a simulation software (HOMER). The peak load, base load and daily average energy consumption were found to be 177 kW, 60 kW and 1864.28 kWh/day respectively. Local energy resource assessment for the site established that solar resource potential is high and suitable for most solar energy applications. Wind energy on the other hand was found to be a Class 1 category which denotes a poor wind resource regime. System simulation and optimization gave positive results for wind-solar and grid hybrid systems. The most optimal system was composed of Wind-Solar PV-Solar Thermal-Grid energy sources with a Net Present Cost and Cost of Energy of KSh 68,927,127 and KSh 7.38/kWh respectively. The Cost of Energy is lower than the utility charges for a commercial consumer charged under the method CI1. Further, this system has a Simple Payback Period of 4.93 years hence making it an attractive project to undertake. The study revealed that hybrid power system utilizing grid connected local energy resources can provide low cost power hence the same can be adopted by commercial consumers with similar energy demands.
