# Marginal Cost of Carbon Sequestration Using Straw-Based Biochar in Great Britain

## TL;DR

This study estimates the cost of using straw-based biochar in Great Britain to help meet the UK's net-zero carbon goals.

## Contribution

The paper introduces a spatial model integrated with life cycle and economic analysis to estimate marginal carbon sequestration costs for straw-based biochar in GB.

## Key findings

- Straw-based biochar in GB can achieve 0.6–1.9% of the UK’s 2050 carbon removal target at marginal costs below £75 per tCO2e.
- Including higher-cost options increases potential removal to 0.8–2.1% of the target.
- Feedstock price, byproduct value, and biochar yield significantly influence marginal costs.

## Abstract

Achieving the net-zero target of the United Kingdom requires
substantial
greenhouse gas removal (GGR) in addition to emission reductions. Biochar,
a stable carbon-rich material produced through biomass pyrolysis,
is an established GGR method. Straw is abundantly available in the
UK and presents a viable option for large-scale biochar production.
However, uncertainties regarding its feasibility remain, particularly
concerning costs, spatial constraints, and facility construction.
Here, we use a spatial model integrated with life cycle assessment
and technoeconomic analysis to estimate the marginal cost curve for
net carbon sequestration through straw-based biochar production in
Great Britain (GB). Our findings reveal that straw-based biochar production
in GB can achieve 0.6–1.9% of the UK’s 2050 carbon removal
target at marginal costs below £75 per tCO2e. If higher-cost
options are also included (i.e., without the £75 per tCO2e constraint), the total potential removal increases to 0.8–2.1%.
The marginal costs are significantly influenced by the price and availability
of feedstock, the value of byproducts, and the biochar yield. Our
integrated spatial model helps identify optimal feedstock supply and
production strategies, reducing costs and uncertainties in net carbon
sequestration for biochar systems. This study elucidates the challenges
and limitations of utilizing straw for large-scale biochar production
in GB to support the climate change mitigation pathway.