Idemitsu Kosan Backs U.S. Startup CREW Carbon to Scale Wastewater Carbon Removal
Japanese energy conglomerate Idemitsu Kosan announced a strategic investment in U.S.-based climate tech startup CREW Carbon. The investment, executed through the company’s corporate venture capital arm (Idemitsu CVC), marks a significant step in Idemitsu’s push into the burgeoning Carbon Dioxide Removal (CDR) and negative emissions markets. Financial terms of the investment were not disclosed.
Co-founded and led by CEO Dr. Joachim Katchinoff, CREW Carbon specializes in capturing carbon dioxide emissions directly from wastewater treatment facilities. The startup is the first company globally to generate certified carbon credits using a methodology known as Wastewater Alkalinity Enhancement (WAE).
Technology and Commercial Viability
CREW Carbon’s proprietary process capitalizes on the natural biological breakdown of organic matter in wastewater, which ordinarily releases CO2. By introducing alkaline materials—specifically calcium carbonate (limestone)—into the treatment process, the CO2 is captured and converted into bicarbonate ions. This treated water is subsequently discharged into river systems and ultimately flows into the ocean, where the carbon remains safely locked away for millennia.
From a capital expenditure standpoint, the technology is highly attractive. Idemitsu noted that CREW’s system requires minimal structural overhaul, requiring only the addition of limestone storage, injection systems, and monitoring equipment to existing wastewater facilities. Furthermore, because inexpensive limestone replaces the standard pH adjusters typically used in wastewater treatment, the process offers a highly cost-competitive approach to carbon removal.
A critical component of CREW’s value proposition is its proprietary Measurement, Reporting, and Verification (MRV) system, which accurately calculates net CO2 reduction—factoring in any subsequent atmospheric release—to ensure data transparency. This robust MRV foundation enabled CREW to issue the world’s first WAE-based carbon credits in May 2025, certified by the U.S. carbon registry Isometric.
Strategic Synergies for Idemitsu
For Idemitsu, the investment is a calculated play to acquire technical know-how in the CDR sector as it pursues its 2050 carbon neutrality targets. Beyond emissions reduction, Idemitsu views carbon removal as an essential growth area and is actively building a portfolio in the “negative emissions” sector.
The partnership also holds strong domestic potential. Because Japan is one of the world’s leading producers of limestone, the primary raw material required for CREW’s process can be sourced domestically with high stability. Idemitsu stated it will work alongside CREW Carbon to evaluate the feasibility of deploying this wastewater CDR solution within Japan and other global markets.
As corporate demand for high-quality, verifiable carbon credits continues to surge globally, Idemitsu’s backing positions both companies to capitalize on an increasingly critical segment of the carbon management economy.