ExxonMobil Faces Antitrust Claims Over Blue Ammonia Project's CO2 Pipeline Access

ExxonMobil and its Denbury subsidiary are facing expanded antitrust claims in Texas after a blue ammonia developer alleged the oil major used its control over carbon dioxide pipelines to block a competing project.

Start-up Clean Hydrogen Works has added ExxonMobil as a defendant in a year-old lawsuit originally filed against Denbury Carbon Solutions. According to Bloomberg Law, the amended petition filed in Texas Business Court describes ExxonMobil's actions as a "Rockefeller-style power play."

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The lawsuit centers on the Ascension Clean Energy (ACE) project, a $7.5 billion blue ammonia facility planned for Louisiana's Ascension Parish. When fully built, the project would produce up to 7.2 million metric tons of clean ammonia annually while capturing approximately 98% of CO2 emissions for permanent underground storage.

Clean Hydrogen Works alleges that after ExxonMobil acquired Denbury in late 2023, the company forced Denbury to terminate existing agreements that would have allowed the ACE project to use Denbury's extensive CO2 pipeline network. That network spans roughly 1,300 miles across the Gulf Coast region, making it the largest liquid CO2 pipeline system in the United States.

The original partnership between Denbury and Clean Hydrogen Works was announced in October 2022. Under that agreement, Denbury had secured exclusive rights to transport and sequester all CO2 captured at ACE for 12 years following startup, with the project expected to generate approximately 12 million metric tons of CO2 annually.

Adding another layer to the dispute, Clean Hydrogen Works claims ExxonMobil blocked their pipeline access while simultaneously developing its own competing blue hydrogen and ammonia project at the company's Baytown, Texas complex. That facility was announced in 2022 and would have been one of the world's largest low-carbon hydrogen plants, capable of producing 1 billion cubic feet of hydrogen per day.

However, ExxonMobil paused the Baytown project in late 2025 due to weak customer demand and difficulty securing sufficient offtake agreements. CEO Darren Woods cited economic uncertainty and an industrial slowdown in Europe as factors limiting demand for low-carbon ammonia.

The timing creates an unusual situation where the alleged victim of anticompetitive behavior, Clean Hydrogen Works, may now be better positioned to move forward than ExxonMobil's own project.

The ACE project had been designed with strategic advantages including proximity to Denbury's existing pipeline infrastructure, Mississippi River access for product shipment, and partnerships with shipping giants Mitsui O.S.K. Lines and Hafnia for global distribution.

ExxonMobil has not publicly commented on the lawsuit, consistent with the company's typical approach to ongoing litigation.

This case highlights the critical importance of CO2 pipeline infrastructure in the emerging low-carbon ammonia sector. As blue hydrogen and ammonia projects compete for limited transportation and storage capacity, control over these networks could significantly influence which projects ultimately reach completion.

The outcome of this Texas Business Court case could set important precedents for how carbon capture infrastructure is shared among competing clean energy developers.