Hydrogen and Ammonia Blending in Existing LNG Infrastructure: A Technical Review of Compatibility, Retrofit Potential, and Conversion Pathways

Abstract

Liquefied natural gas (LNG) has long been regarded as a transition fuel, yet growing concerns over life-cycle greenhouse gas emissions have intensified interest in retrofit options for existing LNG infrastructure. This review examines whether hydrogen and ammonia can be introduced into the LNG value chain through blending, co-firing, and partial repurposing of existing assets. It synthesizes evidence across five infrastructure segments: liquefaction, marine transport, regasification and storage, pipeline distribution, and end-use combustion. The review finds that hydrogen is currently the more mature option for pipeline transmission and distribution, with pilot and demonstration projects supporting blends of around 20% by volume. However, material compatibility, leakage, metering, and end-use constraints remain important barriers. Ammonia offers advantages in storage and shipping because of its established handling legacy, but its combustion performance, toxicity, and retrofit requirements limit near-term deployment, especially in gas turbine applications. Liquefaction terminals appear to be the least suitable segment for either fuel because existing cryogenic process trains are optimized for methane and show limited compatibility with hydrogen or ammonia. Overall, the evidence suggests that retrofit strategies should be segment-specific rather than uniform: hydrogen is more promising for pipeline-oriented repurposing, ammonia is more suitable for storage- and logistics-oriented applications, and both fuels face substantial technical and regulatory barriers in LNG liquefaction systems.