Exploring carbon dioxide removal strategies to help decarbonise Europe using high-resolution modelling

TL;DR

This study extends a high-resolution European energy system model to include various carbon dioxide removal strategies, demonstrating that a combination of these methods can achieve climate neutrality more cost-effectively without relying solely on direct air capture.

Contribution

The paper introduces additional CDR strategies into a high-resolution model and shows their full utilization and impact on achieving cost-effective climate neutrality in Europe.

Findings

A climate-neutral system is 9% less expensive with added CDRs.

Afforestation, perennialisation, and ERW are fully utilized across regions.

DAC is unnecessary when combining CDRs with underground sequestration and transport.

Abstract

The electrification of energy demand across sectors, powered by solar and wind generation, is the best strategy for achieving carbon neutrality. Carbon dioxide removal (CDR) strategies are also expected to play a crucial role by providing net-negative emissions that can offset residual CO2 emissions, including those from cement manufacturing. While previous studies have assessed the role of CDRs in Europe's decarbonisation, most either focus solely on combinations of biogenic point-source capture and direct air capture (DAC) coupled with underground sequestration, or consider multiple CDR strategies at low spatial and temporal resolution, thereby limiting the representation of linkages amongst technologies. In this study, the sector-coupled European energy system model PyPSA-Eur is extended to include afforestation, perennialisation, biochar, and enhanced rock weathering (ERW) as additional CDR strategies. Using this model with a 3-hourly resolution and a network comprising 90 nodes, results show that a climate-neutral energy system equipped with these CDR strategies is 9% less expensive. Afforestation, perennialisation, and ERW potentials are fully utilised across regions, whereas biochar is not selected due to limited solid biomass feedstock being allocated to other higher-value processes. Furthermore, when these CDR strategies are combined with underground sequestration and a continental CO2 transport network, DAC is no longer required to achieve climate neutrality in Europe.