A new study published on arXiv (Fernandes et al., March 2026) extends the sector-coupled European energy system model PyPSA-Eur to include four CDR pathways that most previous models have ignored or underweighted: afforestation, perennialisation, biochar, and enhanced rock weathering (ERW).
The results are striking — and structurally important for anyone thinking about CDR deployment priorities in Europe.
The Core Finding: CDR Makes the System 9% Cheaper
The model, run at 3-hourly resolution across 90 European nodes, finds that a climate-neutral energy system equipped with these CDR strategies is 9% less expensive than an equivalent system that relies only on direct electrification and point-source capture.
That’s a material number. It means CDR isn’t just an environmental nice-to-have — it’s an economic lever for decarbonization.
What Gets Selected: Afforestation, Perennialisation, ERW — Not Biochar
Here it gets interesting for portfolio thinking:
- Afforestation, perennialisation, and ERW are fully utilized across regions — meaning the model deploys them to their maximum technical potential.
- Biochar is NOT selected. The reason: limited solid biomass feedstock gets allocated to higher-value processes elsewhere in the energy system. Biochar competes with bioenergy for biomass, and in a optimized European energy system, that competition goes to bioenergy.
- DAC is no longer required to achieve climate neutrality — but this finding depends on one critical infrastructure assumption (see below).
The CO2 Transport Network Assumption
The key enabling condition: the model includes a continental CO2 transport network and underground geological sequestration. With that infrastructure in place, DAC becomes redundant because the other CDR pathways plus sequestration do the job.
Without a CO2 transport network, the picture changes — but the paper doesn’t show the counterfactual explicitly. What it does show clearly is that CDR pathway selection is infrastructure-dependent. Build the pipes, and the CDR mix shifts.
Why This Matters for CDI’s ERW Focus
CDI’s ERW worldview — that enhanced rock weathering is one of the most scalable and underappreciated CDR pathways — gets some rare modeling support here. ERW is fully utilized in the model across European regions. The paper models ERW as accelerated silicate weathering, using crushed rock spread on agricultural land to enhance natural carbon sequestration through mineral dissolution.
That’s consistent with what CDI’s Head of Science has been saying about ERW’s potential: passive, land-based, scalable without biomass constraints.
What the Paper Doesn’t Tell Us
The model is European and energy-system-focused. It doesn’t account for:
- Global supply chains for CDR feedstocks
- Verification and MRV challenges for ERW and afforestation
- Permanence questions for biochar versus geological storage
- Land competition between afforestation and agriculture at scale
It’s one model. But it’s one of the more rigorous European-sector-coupled analyses available, and it rewards the intuition that CDR diversity matters more than single-pathway bet.
Source: arXiv:2603.25663 — Fernandes et al., “Exploring carbon dioxide removal strategies to help decarbonise Europe using high-resolution modelling” (March 2026)