Idemitsu Kosan Co Ltd. has closed a debt facility with German carbon dioxide removal company InPlanet GmbH, stepping up its efforts to support the commercial expansion of enhanced rock weathering (ERW) as a durable carbon removal technology.
The financing was arranged through Idemitsu’s wholly owned U.S. subsidiary, Idemitsu Americas Holdings (IAH). The Japanese energy company said it plans to support InPlanet’s expansion while exploring broader collaboration on carbon removal market development in North America, Japan and Asia, joint projects and policy coordination.
InPlanet is commercializing ERW in Brazil, where finely crushed silicate rock is spread over farmland to accelerate natural weathering. The process converts atmospheric CO₂ into stable bicarbonate ions that can remain stored in waterways for long periods.
The technology is gaining attention as companies and governments seek carbon removal solutions that can complement emissions reductions on the path to carbon neutrality by 2050. ERW can also deliver potential agricultural benefits, including improved soil fertility and reduced use of fertilizer and limestone.
InPlanet has partnered with quarries and farmers across Brazil’s agricultural regions to deploy ERW. In December 2024, the company delivered what it described as the world’s first independently verified ERW carbon removal credits under Isometric’s Enhanced Weathering Protocol.
The company is also developing measurement, reporting and verification systems to quantify atmospheric CO₂ removal from its operations, while strengthening its commercial model through long-term offtake agreements and carbon delivery insurance.
Idemitsu said it sees InPlanet as a promising ERW partner based on the company’s commercial, technical and operational experience. The two companies aim to build expertise in ERW, support InPlanet’s growth, expand Idemitsu’s carbon removal business and contribute to the development of the wider CDR market.
IAH President and CEO Masanori Abe said: "InPlanet's efforts in Brazil combine scientific rigor with hands-on application, making them an important player in advancing durable CDR from the demonstration stage to full-scale deployment. This funding is an important step to deepen our understanding of durable CDR and support its development. Going forward, we will continue to contribute to the overall development of the CDR market through collaboration and knowledge sharing with InPlanet.”
Enhanced rock weathering is one of several high-durability carbon dioxide removal approaches being developed globally. Other technologies include biochar, direct air carbon capture and storage (DACCS), and bioenergy with carbon capture and storage (BECCS).
