A unique biomass based integrated energy system for cleaner production of multiple energy outputs for sustainable communities

Development of integrated energy systems where food wastes are converted into useful forms of energy is critical for establishing sustainable communities. In this study, a unique integrated energy system is developed and comprehensively analyzed to provide clean and sustainable electricity, biomethane, hydrogen, and heating from organic biomass energy and off-peak period excess electricity. An application of the developed system is considered for the Durham Region in Ontario, Canada. The organic food wastes collected under the Durham's green bin program are anaerobically digested to produce biogas. A high-pressure water scrubbing technique is utilized to upgrade the produced biogas to high purity biomethane. Excess electricity available during off-peak energy periods in the region is utilized for hydrogen production via proton exchange membrane water elec-trolysis. The produced biomethane and hydrogen is blended to synthesize an energy-dense fuel that is considered for power and heat generation via a combined regenerative gas-steam power cycle as well as a cleaner fuel for public transit buses in the region. On an annual basis, the proposed system provides about 1966 tons of bio-methane from food wastes and about 298 tons of H2 from excess off-peak electricity in the Durham Region. Furthermore, the current integrated system is capable of producing 10.72 MW of electricity and 7.5 MW of heat for space heating and hot water applications. The overall energetic and exergetic efficiencies of the system are obtained as 67.25% and 45.16%, respectively.

Automated summary

Development of integrated energy systems to convert food wastes into useful forms of energy is vital for sustainable communities. A unique integrated energy system is developed and analyzed in this study, providing clean and sustainable electricity, biomethane, hydrogen, and heating from organic biomass energy and off-peak period excess electricity. The system demonstrates the conversion of food wastes to biogas, upgrading biogas to biomethane, and utilizing excess electricity for hydrogen production. The system has significant potential in terms of energy output and efficiency.