Aptamus eyes dual-cargo Jones Act ATB for methanol, LCO2

Aptamus Carbon Solutions, Tampa, Fla., and Demeter Energy, Fort Myers, Fla., have signed a memorandum of understanding to develop a CO2 marine terminal and transportation system tied to a proposed biomethanol plant at Seaport Manatee, with Aptamus now eyeing a Jones Act articulated tug-barge capable of carrying methanol and liquefied CO2 simultaneously. 

Demeter’s proposed facility is expected to produce approximately 100,000 metric tons of low-carbon biomethanol annually while capturing about 200,000 metric tons of CO2 per year. Under the proposed system, Aptamus would receive the captured CO2, liquefy it for marine transport and move it from Florida to Texas or Louisiana for permanent sequestration or enhanced oil recovery. 

Kent Merrill, vice president of marine operations at Aptamus, told WorkBoat that the dual-cargo vessel remains conceptual but is beginning to move toward preliminary design.

“It’s conceptual, but it is moving into preliminary, and we’re starting to run through the challenges and the regulations,” Merrill said. 

Aptamus currently expects the vessel to take the form of an ATB rather than a self-propelled tanker. Merrill said the projected annual cargo volume would likely result in a relatively small tanker, while the ATB approach could also allow additional units to be added as transportation demand increases. 

The vessel is being developed to carry the two cargoes at the same time using separate tank arrangements.

“We think that it’ll be at the same time, simultaneously, because the tanks for the liquefied CO2 will be totally different than the methanol tanks,” Merrill said. “The methanol tanks will be a little more traditional gravity tanks integral with the hull, whereas the LCO2 tanks are going to be Type C pressurized tanks.” 

Both cargoes are expected to move from Florida toward Texas or Louisiana, Merrill said. While methanol could theoretically be carried in the CO2 tanks on a backhaul, that is not the operating pattern currently envisioned for the Demeter project. 

The new vessel will draw on work Aptamus has already completed for a larger LCO2 ATB developed for its T RICH and COAST 20 projects. That design received Approval in Principle from ABS in May 2025. Merrill said lessons from that project, including Type C tank placement, supports and structural loads, will carry into the smaller dual-cargo design. The addition of methanol tanks integral with the hull introduces another design consideration. 

Aptamus has also been selected for U.S. Department of Energy awards supporting design and engineering work for a CO2 loading and processing terminal at Port Tampa Bay and a discharge terminal at LBC Tank Terminals in Sunshine, La. 

Under the new MOU, Aptamus will evaluate potential locations for a CO2 terminal at Seaport Manatee, develop a site plan and advance the vessel concept. The proposed vessel is intended to be U.S.-built, U.S.-flagged, U.S.-owned and crewed by U.S. mariners in accordance with Jones Act requirements. 

The project must still move through feasibility work and more detailed engineering before an investment decision is made. Merrill said Aptamus believes enough engineering could be completed to support a financial investment decision within about a year.

If the project advances from there, detailed design and construction could take as little as 2½ to three years, he said, assuming the project proceeds as planned. 

Aptamus is an affiliate of Overseas Shipholding Group and part of the Saltchuk family of companies.