Marine Carbon Dioxide Removal: The Strategic Bridge to IMO Compliance
Shipping companies around the world face a potential $100/ton carbon tax as part of landmark net-zero emissions regulations drafted by the International Maritime Organization. A clear signal of growing ambition to decarbonize maritime shipping, it the first framework in the world to combine mandatory emissions limits and GHG pricing across an entire sector. Operators must act now to secure competitive advantages, while avoiding potentially crippling financial penalties.
The IMO net-zero framework is set to be formally adopted in October 2025 and to enter into force in 2027.
October 2025 (MEPC/ES.2): Adoption of the amendments during an extraordinary session of the Marine Environment Protection Committee.
Spring 2025 (MEPC 84): Approval of detailed implementation guidelines.
2027: Expected entry into force, 16 months after adoption (in accordance with MARPOL articles).
For shipping companies, this means cost-effective compliance strategies need to be implemented as soon as possible. But alternative shipping fuels and emission reduction or avoidance technologies are far from being implemented at scale. Learning from similar trends in the aviation industry, carbon credits are likely to be accepted as a near-term bridge on the path to net-zero, and the best time to secure the affordable supply is now.
Marine carbon dioxide removal (mCDR) is particularly suited to the maritime industry. Unlike other carbon removal approaches, mCDR has a strong synergy with maritime shipping operations – and shipping companies are well-poised to integrate mCDR into their existing operations.
Here’s why:
Immediate Economic Advantage: mCDR offers immediate cost savings over alternative compliance pathways, particularly compared to expensive low-carbon fuels.
Proven Scalability and Readiness: mCDR technologies can scale rapidly without requiring vast infrastructure changes or vessel modifications.
Supply Gap Mitigation: mCDR offers a critical bridge solution during the significant clean fuel supply gap projected through 2030.
The Economic Case for mCDR as a Compliance Strategy
The IMO's new carbon pricing mechanism creates yet another headwind for shipping companies already facing “uncertainty, rerouting and trade havoc” thanks to the US tariffs remaking the global economy. Under its framework, vessels must meet progressive reduction targets for greenhouse gas intensity (from 17% in 2028 to 43% by 2035 compared to the 2008 baseline) or pay a minimum $100/ton carbon levy on emissions above this threshold. Missing the weaker targets (4% in 2028 to 30% by 2035) incurs a much higher penalty of $380/ton.
From an economic perspective, if approved in the framework, offsetting emissions with mCDR presents a compelling advantage over switching right now to alternative fuels. High-sulfur fuel oil (HSFO) with a carbon intensity of ~94 gCO2e/MJ remains the most economical fuel option from an operational perspective. To meet the tougher 2030 target (21% reduction) through fuel switching would require blending ~34% UCOME (used cooking oil methyl ester) at approximately 3x the cost of HSFO. According to the UCL Energy Institute assessment, biofuels will be the primary beneficiary of this system in the short term but face significant supply constraints.
Gigablue, the largest mCDR developer to date, has pioneered MCFS (Marine Carbon Fixation and Sequestration) technology – a solution that delivers one of the most competitive dollar to ton removal ratios of any CDR approach.
This approach allows shipping companies to maintain their existing business models, vessel designs, and operational practices while achieving compliance – allowing them to save money by avoiding premature fleet renewal costs.
Deployment Ready: Implementation Without Infrastructure Delays
The second major advantage of mCDR solutions is their readiness for rapid deployment. Unlike alternative fuels that require global infrastructure changes, mCDR can be implemented without modifying vessels or establishing new supply chains.
In fact, Gigablue's MCFS technology uses "water and sunlight" as primary inputs. There is no need to wait for facilities or other infrastructure to be built – Gigablue's solution is fully operational today at the scale shipping companies require offset emissions immediately. The company has already demonstrated commercial viability through its 200,000-ton CO2 removal agreement with SkiesFifty – the largest marine carbon removal agreement to date.
With the IMO’s new regulations expected to take full effect within two years and at least 10-25 years of operational life remaining on most vessels, it is unlikely that entire fleets will be able to undergo significant enough transformations. Marine CDR, however, can be implemented immediately.
Solving the Clean Fuel Supply Gap
Perhaps the most compelling case for mCDR comes from the severe mismatch between supply and demand projections for clean marine fuels. International shipping currently consumes approximately 300 million tons of marine fuel annually, resulting in ~1 billion tons of CO2 emissions (3% of global emissions). Under business-as-usual scenarios, emissions could increase 90-130% by 2050 without intervention.
The IMO's requirement for 5-10% zero or near-zero GHG fuels in shipping's energy mix by 2030 would represent 15-30 million tons of alternative fuel. Current production capacity and announced projects for marine biofuels, e-methanol, green ammonia, and other alternatives will not be able to meet this demand by 2030. Even if all announced clean fuel projects are completed on schedule, the supply gap remains enormous.
Biofuels are particularly limited, with total global biofuel production at approximately 159 billion liters in 2022; marine shipping alone would require hundreds of billions of liters to achieve compliance. Green ammonia and hydrogen production capacities remain in early development, with negligible current supply compared to demand.
The Strategic Role of Gigablue's Safe & Proven mCDR Solution
Gigablue's technology offers distinctive advantages that make it particularly well-suited to address shipping's carbon challenge while avoiding ecological risks.
Marine carbon fixation and sequestration (MCFS) uses Gigablue’s proprietary substrate that optimizes phytoplankton growth. The substrates ensures rapid, controlled sinking of carbon-rich biomass to the deep ocean for long-term sequestration. The reliance on abundant, natural inputs (sunlight, water, and gravity) creates a fundamentally scalable approach. As one of the most cost-effective, high-quality CDR solutions operational in the world today, Gigablue will ideally positioned to provide an affordable large-scale solution to the entire industry when carbon credits become eligible in the IMO’s net-zero framework.
Gigablue’s methodology has been validated by world-leading scientific institutions, including New Zealand's National Institute of Water and Atmospheric Research (NIWA). The technology and materials have been rigorously assessed by Cawthron, the largest independent science center in New Zealand, and scientifically confirmed to be non-toxic with less than minimal environmental effects.
Designed for gigaton-scale carbon removal, Gigablue's technology aligns with the shipping industry's massive emissions footprint and is market-ready today.
The Pragmatic Path Forward
The historic IMO net-zero framework creates an urgent need for compliance strategies. While alternative fuels and efficiency technologies represent the long-term solution, the economic, scalability, and supply gap challenges make them impractical as the sole near-term strategy. Marine carbon dioxide removal (mCDR), and Gigablue's approach in particular, offers the shipping industry a pragmatic path that:
Provides immediate compliance at lower cost than alternative fuels
Can be implemented without major operational changes
Bridges the significant clean fuel supply gap projected through 2030
By incorporating mCDR into their decarbonization strategy, shipping companies can achieve immediate regulatory compliance while maintaining their existing operations. Partnering with Gigablue to offset emissions above regulatory thresholds provides a pragmatic bridge strategy—supporting compliance today and offering flexibility as clean fuel markets and regulations continue to evolve. When carbon credits become eligible in the framework, this balanced approach will represent the most economically sound and realistic path to meeting the IMO’s emissions reduction goals.
