In a world grappling with the urgent need to curb carbon emissions, a groundbreaking study published by the Potsdam Institute for Climate Impact Research (PIK) and Humboldt University of Berlin sheds new light on the complex landscape of carbon dioxide removal (CDR) technologies. Led by Quirina Rodriguez Mendez, the research delves into the deep uncertainties surrounding the costs and resource limits of various CDR options, offering a roadmap for designing robust portfolios that can withstand the vagaries of future scenarios.
The study introduces a novel mixed-integer linear optimization model, aptly named the CDR sustainable portfolios with endogenous cost model. This model is designed to navigate the treacherous waters of cost-optimal and time-dependent CDR portfolios, taking into account the dynamic nature of technology costs. “The key challenge,” explains Rodriguez Mendez, “is the deep uncertainty in three critical dimensions: realizable mitigation potentials, cost dynamics, and resource constraints. Our model helps to illuminate the path forward by providing a framework that can adapt to these uncertainties.”
The findings are both enlightening and somewhat surprising. Afforestation and reforestation, along with soil carbon sequestration, emerge as robust options that are likely to be deployed regardless of the removals required. These nature-based solutions offer a reliable anchor in the stormy seas of CDR uncertainties. Direct air carbon capture and storage (DACCS) stands out as the most deployed technology by 2100, with a median value of 6.7 gigatons of CO2 per year. However, the range of possible outcomes is vast, stretching from 4 to 8.7 gigatons of CO2 per year, depending heavily on future renewable energy capacity and geological storage injection rates.
Bioenergy with carbon capture and storage (BECCS) faces severe constraints due to land availability, with the median deployment falling from 1.8 to 0.3 gigatons of CO2 per year in land-constrained scenarios. Yet, when future energy availability is bounded, BECCS gains a larger share in the portfolio. The study also reveals that ocean alkalinization could become a dominant solution in high removal scenarios, adding another layer of complexity to the CDR landscape.
For the energy sector, the implications are profound. The study provides a framework to explore trade-offs across different aspects relevant to planetary boundaries, moving beyond mere economic costs. This holistic approach is crucial for decision-makers in the energy industry, who must navigate the delicate balance between economic viability, environmental sustainability, and technological feasibility.
The research, published in the journal Environmental Research Letters, translates to English as ‘Letters on Environmental Research,’ underscores the need for a nuanced understanding of CDR technologies. As the world races to meet its climate goals, this study offers a beacon of clarity in a field fraught with uncertainty. It challenges the energy sector to think beyond conventional wisdom and embrace a more adaptive, resilient approach to carbon management.
The insights from this research are set to shape future developments in the field, pushing the boundaries of what is possible and necessary in the fight against climate change. As Rodriguez Mendez aptly puts it, “The future of carbon management is not about picking winners and losers, but about building a portfolio that can adapt and thrive in the face of deep uncertainty.” This study is a significant step towards that future, offering a roadmap for a more sustainable, resilient energy landscape.
