Bioenergy with carbon capture and storage (BECSS): Life cycle environmental and economic assessment of electricity generated from palm oil wastes

Abstract

Rapid deployment of negative emissions technologies (NETs) will be needed to help mitigate climate change. Among various NETs, bioenergy with carbon capture and storage (BECCS) is seen as an option with multiple environmental benefits, including increasing the share of renewable energy while capturing carbon and providing an effective solution for waste management if waste biomass is utilised. This research presents the first environmental and economic sustainability assessments of BECCS utilising palm oil waste abundant in palm oil producing countries, such as Malaysia. The following five types of waste are considered: fronds, trunks, empty fruit bunches (EFBs), shells and fibres. Process simulation, techno-economic analysis and life cycle assessment (LCA) are combined to determine the life cycle impacts and costs of BECCS from cradle to grave. Two units of analysis are considered for both the impacts and costs: ‘generation of 1 MWh of electricity’ and ‘capture of 1 tonne of CO2’. The global warming potential (GWP) is net-negative for both functional units, ranging from −1270 to −1410 kg CO2 eq./MWh and −840 to −1729 kg CO2 eq./t CO2 removed, the latter depending on the credits for electricity generation. However, all other 17 impacts increase by 13–217% with the addition of CCS. The systems without CCS have net-positive GWP of 59–126 kg CO2 eq./MWh. Per MWh electricity, the system with fibres has the lowest and palm fronds the highest impacts for most of the categories considered; per tonne of CO2 removed, there is no clear feedstock preference. The levelised costs of electricity (LCOE) of BECSS plants are US$98–119/MWh, with fibres being the best and fronds the worst feedstock. Compared to the systems without CCS, the LCOE of BECCS are 3.6–4.1 times higher. The costs of BECSS per tonne of CO2 removed are US$66–74, with CCS contributing US$50–53/t CO2. Based on the current availability of palm oil wastes in Malaysia, the system could generate 7730 GWh/yr, boosting the national share of bioenergy by 7.6 times, while removing 12 Mt CO2/yr, equivalent to 10% of annual emissions from the electricity sector.