The carbon footprint is the internationally recognised reference standard for calculating the CO2e impact of an organisation or product over its entire life cycle. At the basis of the Biogas Optitool© calculation system is a cradle-to-gate study, i.e. from the storage of livestock manure and other biomass to the storage of digestate/other co-products at farms. The latter can be both feeders and users of digestate. With regard to livestock manure, the calculation of CO2e savings compared to a situation without a plant with regard to methane and nitrous oxide emissions, the bibliographical data were found to be incomplete. A ‘typical farm’ (in terms of size and type of livestock) was therefore identified that was representative of the biogas plant’s feeders. Chemical and physical characterisation analyses and biochemical methanogenic potential (BMP) tests were then conducted on a series of livestock effluent samples. Based on methodologies proposed by the IPCC, these experimental data were then processed by cross-referencing them with literature studies, establishing a CO2e trend curve for storage, depending on storage duration and ambient temperature. The company owning Biogas Optitool© is certified with CFP Systematic Approach by Bureau Veritas Italia Spa in accordance with the ISO 14067:2018.
