| Abstract [eng] |
In the face of the problem of climate warming, the need to seek sustainable methods and decarbonization technologies to reduce the damage of climate change to the environment increases. Biochar or bioenergy carbon capture and storage (BECCS) technology attracts considerable attention as a means of CO2 storage and climate change mitigation. Biochar produced through biomass pyrolysis, which is a solid carbon material similar to charcoal, not only provides a long-term storage solution for carbon but also improves soil properties. This research is concentrated on a comprehensive assessment of the environmental footprint and carbon storage potential of biochar production, and use, specifically comparing two different biomass sources. The cradle-to-grave analysis of life cycle emissions of biochar using Life Cycle Assessment (LCA) methodology for a functional unit of 130 kg biochar from cleft timber/sewage sludge, is performed. To produce 130 kg of biochar, 1 t of cleft timber/ 5 t of sewage sludge are used by performing pyrolysis. Four cycle phases were considered: biomass production, transport, production, and use. The SimaPro 9.1 software, Ecoinvent v.3.6 database5, PURO2 guidelines, and data from a biochar production facility based in Lithuania have been used to perform that analysis. Furthermore, the evaluation of life cycle greenhouse gas emissions was carried out by applying the IPCC GWP100a v1.03 method and assessment of impact categories by ReCiPe 2016 method. Results present that life cycle stage biochar production in the case study is the biggest contributor to climate change, resulting in 146 kg of CO2 eq (IPCC GWP100a v1.03 method). The same pattern is spotted in the life cycle assessment of biochar from sewage sludge, with results of 322.3 kg CO2 eq. On the other hand, the phase biochar use, where final product biochar is used in the soil because of its gradual release of carbon resulting in progressive enrichment of the soil, generated 6.6 kg CO2 eq in both cases. Overall, it was also indicated that the amount of carbon sequestered over a 100-year time horizon by the amount of biochar manufactured from cleft timber is equal to 425.3 kg CO2 eq and by the biochar from sewage sludge is – 255.3 kg CO2 eq. Although greenhouse gas emissions are highest during biochar production in both cases, the study concludes that biochar's application in soil from cleft timber has a positive effect on the environment due to carbon storage, yet biochar from sewage sludge resulted in a negative net amount of CO2 sequestered, meaning unsuccessful climate mitigation. Therefore, the study suggests that the biochar from cleft timber can be a viable net-negative technology for climate change mitigation, and pyrolysis of sewage sludge is a good way to manage waste before further analysis on the characteristic of biochar from sewage sludge is conducted. |
