Global biomethane and carbon dioxide removal potential through anaerobic digestion of waste biomass

Abstract

Anaerobic digestion is a bioenergy technology that can play a vital role in achieving net-zero emissions by converting organic matter into biomethane and biogenic carbon dioxide. By implementing Bioenergy with Carbon Capture and Storage (BECCS), carbon dioxide can be separated from biomethane, captured, and permanently stored, thus generating carbon dioxide removal (CDR) to offset hard-to-abate emissions. Here, we quantify the global availability of waste biomass for BECCS and their CDR and biomethane technical potentials. These biomass feedstocks do not create additional impacts on land, water, and biodiversity and can allow a more sustainable development of BECCS while still preserving soil fertility. We find that up to 1.5 Gt CO2 per year, or 3% of global GHG emissions, are available to be deployed for carbon removal worldwide. The conversion of waste biomass can generate up to 10700 TWh of bioenergy per year, equivalent to 10% of global final energy consumption and 27% of global natural gas supply. Our assessment quantifies the climate mitigation potential of waste biomass and its capacity to contribute to negative emissions without relying on extensive biomass plantations.

Cost-competitive decentralized ammonia fertilizer production can increase food security

“…In the bioenergy route, hydrogen and carbon dioxide would be produced from steam methane reforming of bio-methane, with additional carbon capture 24 . However, both electrolytic and biogenic hydrogen are subject to constraints of local renewables and feedstock availability 25 , 26 . In addition, an infrastructure upgrade would be required to transport hydrogen and carbon dioxide 27 .…”

Optimal Combination of Net-Zero Pathways for Minimum Energy, Land, and Water Consumption in Chemical Production

“…Ideally, the biomass used to produce chemicals is “sustainable”. Although there is no clear and globally accepted definition for sustainable biomass, we define it here as waste and residues biomass, which is grown without generating additional environmental impacts on the ecosystem (e.g., no loss of biodiversity). ,, Sustainable biomass can consist of crop residues, forestry residues, food waste, and livestock manure …”

“…6 However, waste biomass and residues do not compete for resources with other biomass uses and have the potential to contribute to a net-zero and sustainable chemical industry. 43,44 Overall, all net-zero pathways come with limitations and substantial energy, land, and water consumption. Given that different countries suffer varying degrees of resource scarcity, the deployment of these technologies must be country-specific so as to not exacerbate the depletion of these resources.…”

“…Finally, achieving net-zero emissions with biomass alone would translate into very large land use and water consumption when assuming to grow biomass purposely for producing chemicals . However, waste biomass and residues do not compete for resources with other biomass uses and have the potential to contribute to a net-zero and sustainable chemical industry. , …”

“…More specifically, an optimization model based on linear programming is formulated and solved to determine the optimal combination of net-zero pathways for producing chemicals with net-zero emissions while minimizing the use of renewable energy, land, and water, and while complying with waste biomass and CO 2 storage availability. Within this context, waste biomass is defined as waste or residue biomass that does not compete for land and water with other sectors . CO 2 storage availability is defined considering available underground capacity .…”