Title: Analysis of solutions alleviating CO2 emissions intensity of biogas technology

Authors: Wojciech M. Budzianowski; Kamila J. Budzianowska; Donata S. Budzianowska

Addresses: Consulting Services, Poleska 11/37, 51-354 Wrocław, Poland ' Consulting Services, Poleska 11/37, 51-354 Wrocław, Poland ' Consulting Services, Poleska 11/37, 51-354 Wrocław, Poland

Abstract: Biogas is a multi-purpose technology capable of harvesting renewable energy, converting organic wastes and supplying low-carbon biofuels for transport which all mitigate atmospheric carbon emissions. State-of-the-art biogas CHP technology is however characterised by relatively significant life cycle CO2 emissions intensity typically ranging from 200 to 450 gCO2eq/kWhe, depending on specific feedstocks and configurations. Due to high CO2 content in biogas, the direct biogenic CO2 emissions intensity of a biogas CHP plant is about 700 gCO2/kWhe, which is greater than the direct CO2 emissions intensity of natural gas combustion and it is comparable only with coal combustion. Therefore, in order to meet requirements of future low-carbon energy systems, solutions capable of cost-effectively mitigating various parasitic or even biogenic carbon emissions from biogas are needed. This study analyses the following categories of solutions alleviating CO2 emissions intensity of biogas technology: 1) anaerobic digestion (AD) of organic matter with increased CH4/CO2 selectivity; 2) biological H2 generation from organic matter; 3) AD with biogenic CO2 recycling; 4) biogas utilisation with facilitated CO2 sequestration; 5) low-carbon biofuels from biogas. For each of these categories solutions aiming at alleviating CO2 emissions intensity are provided and analysed. Finally, optimal embedding in the economic environment is discussed.

Keywords: biogas; CO2; carbon dioxide; carbon emissions; emissions intensity; low-carbon energy; anaerobic digestion; CHP; combined heat and power; hydrogen generation; organic matter; carbon sequestration; low-carbon biofuels.

DOI: 10.1504/IJGW.2016.076334

International Journal of Global Warming, 2016 Vol.9 No.4, pp.507 - 528

Received: 29 Oct 2014
Accepted: 22 Dec 2014

Published online: 04 May 2016 *

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