Feasibility study of using a biogas engine as backup in a decentralized hybrid (PV/wind/battery) power generation system – Case study Kenya

• Published in: Energy (Oxford) 2015-10, Vol.90 (2), p.1830-1841
• Main Authors: Ghaem Sigarchian, Sara, Paleta, Rita, Malmquist, Anders, Pina, André
• Format: Article
• Language: English
• Subjects: Biogas engine; Decentralized energy system; Energiteknik; Energy Technology; HOMER; Polygeneration; Rural electrification; Techno-economic optimization
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2015.07.008

In this study, a hybrid power system consisting of PV (Photovoltaics) panels, a wind turbine and a biogas engine is proposed to supply the electricity demand of a village in Kenya. The average and the peak load of the village are around 8 kW and 16.5 kW respectively. The feasibility of using locally produced biogas to drive a backup engine in comparison to using a diesel engine as backup has been explored through a techno-economic analysis using HOMER (Hybrid Optimization Model for Electric Renewables). This hybrid system has also been compared with a single diesel based power system. The results show that the hybrid system integrated with the biogas engine as backup can be a better solution than using a diesel engine as backup. The share of power generation by PV, wind and biogas are 49%, 19% and 32%, respectively. The LCOE (Levelized Cost of Electricity) of generated electricity by this hybrid system ($0.25/kWh) is about 20% cheaper than that with a diesel engine as backup ($0.31/kWh), while the capital cost and the total NPC (Net Present Cost) are about 30% and 18% lower, respectively. Regarding CO2 emissions, using a biogas engine as backup saves 17 tons of CO2 per year compared to using the diesel engine as backup. •We did a feasibility study on a hybrid energy system with biogas engine as backup.•We compared using biogas and diesel engine as backup in the hybrid energy system.•Using locally-produced biogas in the hybrid system decreases the CO2 emissions.•Using the biogas engine as backup decreases the LCOE of the hybrid system.•Locally-produced biogas can be a good substitute for diesel in the hybrid system.