Carbon Dioxide Removal: A Portfolio of Solutions
The fight against climate change requires more than just reducing emissions—it demands actively removing carbon dioxide (CO₂) from the atmosphere and storing it securely for the long term. This is where Carbon Dioxide Removal (CDR) technologies come in. These methods are designed to pull CO₂ out of the air and lock it away, helping to counterbalance emissions that are difficult or impossible to eliminate entirely. But no single solution can do it all. Each CDR method has its strengths and weaknesses, and together they form a toolkit we can use to tackle the climate crisis.
Afforestation/Reforestation (A/R)
Planting or restoring forests is one of the most natural ways to remove CO₂ from the atmosphere. Trees absorb CO₂ as they grow, storing it in their trunks, branches, and roots. It’s a simple, cost-effective solution that also provides other benefits like improving biodiversity and protecting ecosystems.
But there’s a catch: forests aren’t permanent carbon sinks. The carbon stored in trees can be released back into the atmosphere through wildfires, disease, or deforestation. This makes A/R vulnerable to reversal, especially as climate change increases the frequency of extreme weather events. While it’s an important tool in our CDR portfolio, it’s not a silver bullet.
Bioenergy with Carbon Capture and Storage (BECCS)
BECCS combines renewable energy production with carbon removal. Here’s how it works: biomass (like crops or wood) is burned to generate energy, and the resulting CO₂ emissions are captured and stored underground instead of being released into the atmosphere. This method offers high durability because the captured CO₂ is locked away in geological formations for thousands of years.
However, BECCS comes with challenges. It requires large amounts of land to grow biomass sustainably, which can compete with food production or lead to deforestation if not managed carefully. Scaling up BECCS also depends on having access to infrastructure for capturing and storing CO₂—something that isn’t yet widely available.
Direct Air Carbon Capture and Storage (DACCS)
DACCS is one of the most high-tech solutions in the CDR toolkit. Machines use chemical processes to capture CO₂ directly from the air, which is then compressed and stored underground. This method is incredibly durable—once stored, the CO₂ stays out of the atmosphere for millennia.
But DACCS is still in its early stages. It’s expensive and energy-intensive, requiring significant advancements before it can be deployed at scale. Despite these hurdles, DACCS holds promise as a long-term solution for removing large amounts of CO₂ from the atmosphere.
Pyrolysis/Biochar
Pyrolysis offers a unique approach to carbon removal by turning waste biomass into biochar—a stable form of carbon that can be stored in soil or used in construction materials for hundreds to thousands of years. The process involves heating biomass (like agricultural residues or forestry waste) in a low-oxygen environment, which prevents it from decomposing or burning and releasing CO₂ back into the air.
What makes pyrolysis stand out is its versatility. In addition to producing biochar, it generates bio-oil (a liquid energy source) and syngas (a mixture of gases that can power the pyrolysis process itself). This means pyrolysis can be energy self-sufficient—or even a net producer of renewable energy.
Unlike other methods that require significant land or energy inputs, pyrolysis uses waste feedstocks that would otherwise decompose or be burned. This makes it a sustainable option with minimal competition for land or food resources.
Why We Need a Portfolio Approach
Each CDR method has its role to play, but none of them can solve the problem alone. Afforestation is inexpensive but vulnerable to reversal; BECCS and DACCS offer high durability but face challenges related to scalability; pyrolysis strikes a balance with high durability, moderate costs (80–350 per ton), and readiness for large-scale deployment.
The key is diversity. By combining these methods into a portfolio approach, we can address different contexts and challenges while minimizing risks. Some solutions may work better in certain regions or industries than others—and that’s okay. What matters is that we use every tool at our disposal to tackle this crisis head-on.
The Unique Role of Pyrolysis-Based Carbon Removal
Among all these tools, pyrolysis stands out as one of the most practical and scalable solutions available today. Its ability to transform waste biomass into valuable products while sequestering carbon durably makes it an indispensable part of our climate strategy.
How Pyrolysis Works
The process begins with waste biomass—things like crop residues, wood chips, or other organic materials that would otherwise decompose or be burned. Instead of letting this material release its stored carbon back into the atmosphere, it’s fed into a pyrolysis reactor where it’s heated in a low-oxygen environment.
This produces three outputs:
Biochar: A stable, carbon-rich material that locks away carbon for centuries when applied to soil or used in construction materials.
Bio-oil: A liquid that can be used as an energy source or stored underground for permanent sequestration.
Syngas: A mixture of gases that can provide renewable energy to power the pyrolysis process itself.
Why Pyrolysis Matters
Pyrolysis doesn’t just remove carbon—it creates co-benefits that make it even more valuable:
Improved Soil Health: Biochar enhances water retention, reduces nutrient runoff, and boosts crop yields—especially in degraded soils.
Renewable Energy Production: The syngas generated during pyrolysis can power the process itself or be used as an additional energy source.
Waste Management: By using agricultural residues and other organic waste as feedstock, pyrolysis helps reduce landfill use and methane emissions from decomposition.
These benefits make pyrolysis more than just a carbon removal technology—it’s a platform for building sustainable systems that support agriculture, energy production, and waste management.
Strategic Recommendations for Scaling Pyrolysis
To unlock pyrolysis’ full potential as a gigaton-scale solution, we need coordinated action across policy, investment, and industry:
For Policymakers
Incentivize Multiple Benefits: Design policies that reward not just carbon removal but also co-benefits like improved soil health and renewable energy generation.
Support Research on Monitoring Systems: Fund long-term studies to improve our understanding of biochar’s durability in different environments.
Promote Decentralized Systems: Encourage smaller-scale pyrolysis units located near feedstock sources (e.g., farms or sawmills). This reduces transportation costs and emissions while fostering local economic development.
For Investors
Focus on Sustainable Projects: Prioritize investments in projects with robust monitoring systems and sustainable feedstock supply chains.
Diversify Revenue Streams: Evaluate projects based on their ability to generate income from multiple sources—carbon credits, biochar sales, energy production—rather than relying solely on volatile carbon markets.
For Industry
Co-locate Facilities with Feedstock Sources: Build pyrolysis units close to farms or forestry operations to minimize transport costs and a steady supply of biomass.
Collaborate Regionally: Work within industrial clusters to share infrastructure for biomass processing and energy distribution.
Conclusion
Pyrolysis-based carbon removal offers something rare: a solution that balances durability, affordability, scalability—and immediate readiness for deployment. It addresses legacy emissions while supporting agricultural sustainability through improved soil health and renewable energy generation.
By investing in this technology now—through supportive policies, strategic investments, and industry collaboration—we have an opportunity not just to mitigate climate change but also to build systems that benefit communities worldwide.
