Pyrogenic Carbon Capture and Storage (PyCCS)

Biochar alone captures 30–50% of the carbon in the original biomass. PyCCS — Pyrogenic Carbon Capture and Storage — showed that by sequestering all three pyrolysis products, the efficiency can exceed 70%, making biomass pyrolysis a serious negative emission technology. The concept, coined by the Ithaka Institute, now has a Wikipedia entry and was cited by the IPCC.

Until 2018, the climate discussion around biochar focused on the solid product alone — the carbon retained in the char after pyrolysis. Since only 30–50% of the feedstock carbon ends up in the biochar, the technology was dismissed by some climate modellers as too inefficient to matter at planetary scale. The liquid and gaseous pyrolysis products, containing the remaining carbon, were treated as energy by-products to be burned.

Schmidt et al. (2019) reframed the problem. The paper introduced the concept of Pyrogenic Carbon Capture and Storage (PyCCS): instead of burning the bio-oil and permanent pyrogas, these products can equally be processed into recalcitrant forms suitable for long-term carbon sequestration — bio-oil injected into geological formations or incorporated into durable materials, pyrogas converted to stable chemicals. When all three carbon streams are sequestered, the total carbon capture efficiency of pyrolysis exceeds 70% of the original biomass carbon. The paper showed that this threshold is critical: below it, the land and biomass requirements for meaningful climate impact are prohibitive; above it, PyCCS becomes competitive with BECCS and direct air capture.

The companion paper by Werner et al. (2018) modelled the biogeochemical potential of PyCCS at global scale, assessing how much biomass pyrolysis could contribute to limiting warming to 1.5°C. The analysis, conducted at the Potsdam Institute for Climate Impact Research, concluded that PyCCS could sequester 0.6–1.6 Gt CO₂ per year by mid-century without competing with food production or exceeding sustainable biomass supply — placing it among the most feasible negative emission technologies in terms of land efficiency and side-effect profile.

The PyCCS concept was developed within the BMBF-funded BioCAP-CCS project (2017–18) and has since entered the standard vocabulary of negative emission research. The concept directly underpins the Global Biochar C-Sink Standard, which certifies not only carbon sinks but also the carbon efficiency of pyrolysis systems.