Optimal bioenergy power generation for climate change mitigation with or without carbon sequestration

Area of Science:

• Environmental Science
• Climate Change Mitigation
• Agricultural Science

Background:

• Global warming mitigation requires atmospheric carbon dioxide removal (CDR).
• Current climate models primarily consider bioenergy with carbon capture and storage (BECCS) for energy-sector CDR.
• Bioenergy-biochar systems (BEBCS) are a potential CDR pathway not yet included in major climate scenarios.

Purpose of the Study:

• To compare the economic viability and deployment potential of BECCS and BEBCS for climate change mitigation.
• To analyze the impact of carbon price and soil fertility improvements on the cost-effectiveness of different carbon dioxide removal technologies.

Main Methods:

• Utilized integrated assessment models (IAMs) and Monte Carlo simulations.
• Evaluated bioenergy production, carbon sequestration potential, and biochar-induced soil fertility improvements.
• Assessed cost-effectiveness across a range of carbon prices.

Main Results:

• BECCS offers higher carbon sequestration and bioenergy yields per unit of biomass compared to BEBCS.
• BEBCS can be more cost-effective at carbon prices below $1,000 Mg⁻¹ C, particularly when biochar significantly enhances agricultural yields.
• At carbon prices above $1,000 Mg⁻¹ C, BECCS is generally the most economical biomass-based CDR technology.

Conclusions:

• The choice between BECCS and BEBCS for CDR depends critically on carbon price and the agricultural benefits of biochar.
• BEBCS presents an opportunity for earlier and potentially cheaper CDR deployment by leveraging soil health co-benefits.
• Future climate mitigation strategies should consider the inclusion and comparative advantages of BEBCS alongside BECCS.