Hitachi, MOL, and JAL Sign MOU for Japan's First Direct Ocean Capture Pilot Test on Kume Island, Okinawa

Hitachi, Ltd., Mitsui O.S.K. Lines, Ltd. (MOL), and Japan Airlines Co., Ltd. (JAL) have signed a Memorandum of Understanding (MOU) to conduct what will be Japan's first pilot test utilizing Direct Ocean Capture (DOC) technology—a method that directly separates and captures CO2 dissolved in seawater. The test will take place on Kume Island, Okinawa Prefecture. The initiative comes as Japan pursues its national goal of carbon neutrality by 2050, with engineered carbon removal increasingly seen as a necessary complement to emissions reductions.

Pilot Test Overview

The three companies aim to confirm the applicability of DOC technology using seawater from the waters surrounding Kume Island, while gathering foundational data on operational challenges and environmental impacts relevant to future deployment along Japan's coastline. The test will employ containerized pilot equipment installed on land at Kume Island, where seawater will be intake-processed to separate CO2.

Kume Island already hosts advanced pilot projects that take advantage of its geographic location, including Ocean Thermal Energy Conversion (OTEC). The island's concentration of ocean research expertise and talent makes it an optimal site for Japan's inaugural DOC pilot test.

Drawing on insights from this project, the three companies will explore broader applications and expansion of DOC technology. Potential directions include local utilization of captured CO2 and promotional and environmental education programs built around the pilot, all intended to contribute to the development of new ocean-based economic value—the Blue Economy.

Background and Rationale

In so-called "hard-to-abate" sectors such as shipping and aviation, where electrification alone cannot easily reduce emissions, offsetting has emerged as a critical complement to direct corporate reduction efforts. As global demand for transport continues to rise, CO2 removal technologies are increasingly viewed as essential tools, creating urgency around establishing engineered approaches that can directly extract CO2.

Building a domestic removal ecosystem is also gaining importance as a means of controlling the future cost of procuring carbon credits from overseas sources—a significant consideration for Japan, which relies heavily on imported energy and carbon offset supplies. All three companies have invested in Captura Corp., a U.S.-based DOC technology developer, through their respective investment subsidiaries and other channels. They have been jointly examining the feasibility of a domestic pilot to prepare for the deployment of Captura's technology in Japan, leveraging each company's specialized expertise.

The companies describe this pilot as a first step toward establishing an island-based, domestically self-sufficient carbon economy in which recovered CO2 could ultimately serve as a feedstock for synthetic fuels, including Electric Synthetic Aviation Fuel (E-SAF).

How DOC Technology Works

DOC directly removes CO2 from seawater. Under natural conditions, seawater absorbs carbon until it reaches equilibrium with atmospheric CO2 concentrations. When CO2 is artificially extracted from seawater, this equilibrium is disrupted, prompting the ocean to draw additional CO2 from the atmosphere to restore balance. Repeating this cycle can effectively reduce atmospheric CO2 concentrations through the ocean as a medium.

CO2 concentration in seawater is approximately 100 to 150 times higher than in the atmosphere. DOC is widely regarded as a promising climate change solution with the potential to capture CO2 at comparatively lower cost and energy consumption. This higher concentration gradient is a key differentiator from Direct Air Capture (DAC), which processes atmospheric air where CO2 exists at roughly 0.04% concentration and requires significantly more energy per ton captured. DOC is part of the broader emerging field of marine carbon dioxide removal (mCDR), which has attracted growing international investment and policy attention.

Roles of the Three Companies

Hitachi: Under its management plan, "Inspire 2027," the Hitachi Group has established its sustainability strategy, PLEDGES, and is leading this initiative. Using advanced analytical instruments and characterization methods from Hitachi High-Tech Corporation, Hitachi will measure and record operating conditions alongside water quality and environmental data, including Dissolved Inorganic Carbon (DIC) and pH levels in seawater. By analyzing this data and implementing Physical AI that feeds insights directly into plant operations, Hitachi seeks to identify and control operating conditions that achieve high energy efficiency. Additionally, by recording and verifying data on the volume of CO2 captured and electricity consumed, Hitachi will contribute to building an MRV (Measurement, Reporting, and Verification) data platform for generating highly trustworthy carbon credits. Hitachi Industrial Products, Ltd. will advance studies on proposing and supplying core equipment for commercial-scale plants. Through the "One Hitachi" collaborative framework, the group aims to establish an intelligent DOC model originating in Japan.

MOL: The MOL Group has positioned its environmental strategy as a key initiative under its group management plan, "BLUE ACTION 2035," advancing decarbonization as an ocean-based social infrastructure company. For this pilot, MOL will draw on the local foundation it established through a comprehensive partnership agreement with Kumejima Town, Okinawa Prefecture, to build cooperative relationships with local stakeholders and prepare the pilot environment. Based on the insights gained, MOL intends to contribute to the expansion of DOC technology adoption and to the creation of new local businesses and regional initiatives on Kume Island.

JAL: As part of its Green Transformation (GX) strategy under the "JAL Group Management Vision 2035," the JAL Group has identified carbon dioxide removal (CDR) technologies as a key initiative. For this pilot, JAL—working alongside Japan Transocean Air Co., Ltd. and Ryukyu Air Commuter Co., Ltd., both of which operate flights to Kumejima—will leverage regional partnerships to lead promotional activities and raise awareness of DOC technology within and beyond the aviation industry. JAL will also evaluate the utility of DOC technology with a view toward future procurement of E-SAF manufactured from captured CO2.

Source: Mitsui O.S.K. Lines