US Maritime Administration (MARAD) application details floating LNG export project off Texas coast
The latest deepwater port licence application submitted to the US Maritime Administration (MARAD) sets out detailed plans for an up to 8.4 million tonnes per annum (mta) offshore floating LNG export facility in the Gulf of Mexico (Gulf of America), incorporating four converted LNG carriers and a 9-km lateral pipeline to shore.
The proposed project is being developed by ST LNG, a joint venture of Sempra Infrastructure Partners and Japan’s Toyota Tsusho, and supported by engineering contractors Wood, Audubon and DORIS.
According to the application, the ST LNG Deepwater Port Development Project will consist of four separate gas processing and liquefaction units located approximately 30 nautical miles off the Texas coast.
Each unit will include four key platform types: a gas treatment platform, a liquefaction platform, an accommodation and utility platform and an LNG transfer platform. These will be supported by a series of mooring dolphins that allow four permanently moored, converted LNG carriers to be stationed there.
The liquefaction platforms will each be paired with one converted LNG carrier, used for liquefied gas storage. These vessels will remain moored and serve as storage units as well as loading points for shuttle tankers.
In total, 36 mooring dolphins will be installed to maintain stationkeeping for the LNG carriers and allow for tandem offloading operations.
Each liquefaction train is modularised, with pretreatment and gas conditioning handled by separate upstream units.
The platforms will be supported by a subsea and topsides infrastructure system connected to shore via a 9-km, 30-inch diameter gas pipeline lateral. This line will tie into a new connection hub receiving gas from four dedicated feeder lines originating onshore.
All offshore construction will be carried out in accordance with the requirements of the US Coast Guard and MARAD, under the Deepwater Port Act.
In addition to the fixed platforms and floating LNG units, the project includes three dedicated tugs to assist with positioning and offloading operations.
The planned offshore port will be capable of loading multiple LNG carriers annually, with export volumes depending on the final liquefaction capacities chosen.
The application notes, “The proposed project consists of four independently functioning systems to provide resilience and operational flexibility.” Each system, it states, “has a gas treatment, liquefaction and storage capability sufficient to support tanker loading operations.”
ST LNG is seeking regulatory approval to commence construction and operation of the port within the designated federal maritime zone.
The estimated cost of the full development was not disclosed in the MARAD filing. However, given the scale of the platform network and marine infrastructure, the project is expected to require a multi-billion dollar investment.
The engineering contractors named in the filing are United Kingdom-based Wood, US firm Audubon and French engineering group DORIS. Their respective roles in the project have not been itemised but are expected to cover design, construction and integration of both offshore and marine systems.
The application, filed 7 July 2025, initiates a public review and stakeholder consultation process overseen jointly by the US Coast Guard and MARAD, including environmental impact assessments, safety reviews and economic viability studies.
If approved, the ST LNG project would join a growing list of Gulf-based liquefaction export developments seeking to offer modular, floating alternatives to conventional onshore terminals.
