Mantel raises $18M to commercialize molten-borate capture

Mantel, a carbon-capture developer, has raised $18 million from Constellation Technology Ventures and Azimut Investments, with existing investors also participating; the round, reported by ESG News, brings the company's total capital raised to $50 million.

The list of deployments behind that number is the more useful measure. Mantel's pipeline now spans power generation, oil and gas, pulp and paper and other industrial sectors, including a project with one of Canada's largest oil and gas producers, selection as carbon-capture technology partner for the planned 1.6-gigawatt TerraSpark Energy Campus in West Virginia, and a system going in at Kruger's Wayagamack Mill in Québec.

The technology behind those deployments is molten-borate capture, designed to cut the cost and energy penalty that have made conventional capture hard to integrate into existing plants, and its modular approach avoids the capital-heavy retrofits that have stalled earlier projects. That is why named deployments, not the round size, mark carbon capture's shift from lab chemistry to industrial contracting.

The investor lineup reinforces that reading. Constellation Technology Ventures is the venture arm of Constellation, one of the largest U.S. producers of low-carbon electricity, so Mantel gains a backer with direct exposure to power markets and utility capital budgets. "This moment is about execution and how fast we can build," said Cameron Halliday, Mantel's CEO. "This round brings in partners who understand large-scale energy infrastructure as we move at the speed this transition demands." Constellation's Kate Norman, senior vice president for commercialization and market development, said the investment reflects the company's interest in "practical, clean-energy solutions, while balancing sustainability and reliability."

That balance has become the central question for carbon capture, which historically stumbled on high capital requirements, significant energy use and difficult integration with existing industrial facilities — the exact obstacles Mantel says its molten-borate chemistry and modular units are built to remove. The companies now signing up as hosts are the evidence that the technology is being tested against industrial timetables.

For transition-finance investors, the round's value is in its test of execution: carbon capture's next stage will be won or lost on project execution, and Mantel is spending its capital on exactly that — named plants, named partners, and a utility venture arm that understands the economics of large-scale energy infrastructure. The TerraSpark campus and the Wayagamack mill will be the first tests of whether the modular promise survives contact with industrial operating schedules.