Reframing anaerobic digestion as a defossilization platform

Abstract

Anaerobic digestion (AD) coupled with carbon capture, utilization, and/or storage (CCUS) is a deployable bioenergy platform that supplies renewable energy and bioresources while valorizing biogenic CO₂ for integrated carbon management on the pathway to net-zero. Framing AD solely as a waste-treatment technology undervalues its broader contribution to defossilization, particularly its capacity to directly substitute fossil-based natural gas, fertilizers, and chemicals. Here, we reconceptualize the role of AD-CCUS in future net-zero policy frameworks by synthesizing recent life cycle assessment findings. We further identify priority research directions, including (i) developing energy-water-resource hubs to enable multi-product ecosystems, (ii) advancing environmental–economic analyses to quantify ecosystem service values derived from bioresource valorization in AD-CCUS systems, (iii) integrating AD-CCUS into CO₂ transport, storage, and e-fuel networks, (iv) leveraging artificial intelligence, digitalization, and digital twins for performance optimization and emissions verification, and (v) establishing governance frameworks and market instruments that recognize biogenic CO₂ as strategic carbon infrastructure. Repositioned in this way, AD-CCUS emerges as a central pillar in the portfolio of solutions for a defossilized economy.