Our Investment in Mantel Capture
Point-source capture of CO₂ via a molten salt technology
At MCJ, we support founders driving the transition from fossil fuels to renewable energy. To get to a fully renewable grid, power generators today face two major challenges: rising electricity demand and the need for reliable energy sources to complement intermittent renewables like wind and solar. The result is a difficult balancing act—existing infrastructure, such as natural gas plants, produces massive emissions. Yet firm, low-carbon baseload power remains essential until a fully clean grid is feasible. Addressing this challenge requires immediate solutions to drastically reduce or eliminate CO₂ emissions from existing power plants and industrial facilities.
To put this into concrete terms, with the rapid expansion of data centers, the growing adoption of electric vehicles, and heightened cooling needs from heat waves, the world is experiencing an unprecedented surge in energy demand after two decades of relative stability. In response, utilities have doubled their projected power needs through 2028, leading states like Georgia, North Carolina, and Virginia to plan dozens of new natural gas power plants over the next 15 years to provide reliable baseload power. At the same time, natural gas remains a critical energy source beyond the grid, fueling a wide range of industrial processes that require behind-the-meter power and heat.
Point source carbon capture has emerged as a promising solution to meet growing energy demands while maintaining progress toward a cleaner grid by sequestering CO₂ directly from the fossil fuel combustion process. To this end, we’re proud to back Cameron Halliday, Danielle Colson, Sean Robertson, and the entire Mantel team in their Series A, co-led by Shell Ventures and Eni Next with participation from Engine Ventures, New Climate Ventures, and others. Keep reading to learn how Mantel reduces industrial CO₂ emissions through their unique carbon capture technology.
What is Mantel?
Boston-based Mantel aims to capture 95% of carbon emissions directly from industrial smokestacks, leveraging a novel high-temperature liquid solvent. This innovative technology uses molten salt that thrives in the high-heat environments typical of industrial processes.
Unlike traditional amine-based systems, which operate at lower temperatures and are prone to degradation in harsh conditions, Mantel's molten borates are specifically designed to handle industrial impurities such as sulfur oxides, nitrogen oxides, ash, and dust. This robustness ensures longer-lasting performance and reliability in demanding industrial settings.
Mantel's system achieves remarkable efficiency by recycling heat through the industrial process rather than generating extra heat for CO₂ release. This approach drastically reduces energy consumption and operational costs, overcoming the energy penalty that burdens traditional solutions like liquid amines. End-to-end, Mantel's carbon capture cuts costs by more than 50% compared to conventional methods, making it a financially attractive solution for industries with high emissions.
Additionally, Mantel's technology integrates seamlessly into existing infrastructure with minimal disruption to ongoing operations. By addressing the limitations of traditional carbon capture technologies, Mantel's molten salt innovation delivers a scalable, cost-effective path to cutting industrial emissions—helping accelerate the global transition to a net-zero future.
Why Did We Invest?
Compelling Founder-Market Fit
Besides its innovative carbon capture solution, a key driver behind our investment in Mantel is the deep expertise and leadership of Cameron, Danielle, and Sean, each of whom brings a unique and valuable skill set to the company.
Cameron Halliday, the company’s CEO, is commercializing his PhD research, leveraging years of academic and industry experience to drive innovation in the field. Cameron developed Mantel’s core molten borate technology as part of his PhD/MBA in Chemical Engineering at MIT. He previously worked with Shell (new energies research & technology group), EGA, and ABB (process safety consulting). Cameron studied Chemical Engineering at Loughborough University, and he’s a member of Forbes 30 Under 30 Energy Class 2023.
Danielle Colson, Mantel’s COO, brings over 10 years of engineering, business operations, and startup experience to the Mantel team. She previously managed operations at natural gas combined cycle power plants at NextEra Energy. Danielle received her MBA from Harvard Business School and a B.S. in Mechanical Engineering from Duke University. She is also a member of Forbes 30 Under 30 Energy Class 2023.
Mantel’s CTO, Sean Robertson, is a nuclear engineer with specialized expertise in molten salt chemistry and material science. He previously worked at Transatomic Power, helping to design a molten-salt reactor. Sean holds his PhD in Nuclear Science and Engineering from MIT, a M.S. in Nuclear Reactor Physics and Engineering from the Université Paris-Saclay, and a B.S. in Chemistry from Mount Allison University.
As the world grapples with the dual challenge of rising energy demand and the urgent need to reduce emissions, we believe technologies like Mantel’s will play a critical role in bridging the gap. Their molten salt-based carbon capture solution doesn’t just offer incremental improvement—it rethinks how industrial decarbonization can be achieved at scale with lower costs and higher reliability. Backed by a deeply technical and mission-driven founding team, Mantel is poised to unlock a cleaner path forward for some of the world’s most emission-intensive sectors.
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