DOWNSTREAM NATURAL GAS UTILITIES ARE INCREASINGLY AT ODDS WITH LOCAL, STATE, AND FEDERAL CARBON REDUCTION GOALS AND ARE INCENTIVIZED TO REDUCE THEIR CARBON FOOTPRINT BY BLENDING LOW-CARBON FUELS INTO THE PIPELINE NETWORK AS ONE DECARBONIZATION PATHWAY. CLEAN HYDROGEN IS CONSIDERED TO BE ONE OF THE PROMISING PATHWAYS FOR REDUCING THE CARBON EMISSION OF GAS UTILITIES AND END USERS1. HOWEVER, THERE ARE TECHNICAL UNCERTAINTIES AND CHALLENGES ASSOCIATED WITH BLENDING HYDROGEN GAS AT HIGH CONCENTRATIONS INTO THE NETWORK. INDUSTRIES THAT UTILIZE HYDROGEN-CONTAINING RESOURCES CONTACTING METALLIC STRUCTURAL MATERIALS INCLUDE ENERGY INDUSTRIES SUCH AS NATURAL GAS PIPELINES AND THERMOELECTRIC OR NUCLEAR POWER PLANTS, AUTOMOTIVE INDUSTRIES THAT PRODUCE ADVANCED AUTOMOTIVE STEEL AND HYDROGEN-POWERED CASES, AND/OR MARINE INDUSTRIES THAT SERVICE OFFSHORE PLANTS AND UTILIZE VESSEL STEELS. HIGH-STRENGTH STEELS USED IN THESE INDUSTRIES ARE PARTICULARLY SUSCEPTIBLE TO HYDROGEN EMBRITTLEMENT. COATING EXISTING PIPELINES WITH PROTECTIVE MATERIALS OFFERS A PROMISING SOLUTION FOR OVERCOMING THIS UNCERTAINTY AND HELPING REDUCE CARBON EMISSIONS MORE QUICKLY, AND WITHOUT THE FULL INFRASTRUCTURE COST OF REPLACING EXISTING NATURAL GAS PIPELINES. HOWEVER, THERE’S NO COMMERCIAL PRODUCT OR SYSTEM AVAILABLE THAT IS SCALABLE AND DEPLOYABLE IN THE TIMEFRAME THE ECONOMY NEEDS TO REACH NET ZERO. WE PROPOSE A NOVEL HYDROGEN BARRIER COATING WITH A MULTILAYER COMPOSITE STRUCTURE OF METAL AND OXIDE, WHICH CAN SERVE THREE PURPOSES: (1) THE METAL INTERLAYER BETWEEN THE STEEL PIPE AND THE OXIDE LAYER PROVIDES PHYSICAL AND MECHANICAL COMPATIBILITY TO PREVENT DELAMINATION OF COATINGS UNDER IN-SERVICE LOADS. (2) THE FORMATION OF EXTENDED SPACE-CHARGE ZONES AT THE OXIDE/METAL INTERFACE REPELS POSITIVELY CHARGED SPECIES. IN THE CASE OF HYDROGEN, WHICH DISSOLVES AS PROTONS IN AN OXIDE, THESE SPACE-CHARGE ZONES CAN BLOCK THE ENTRY OF HYDROGEN COMPLETELY. (3) THE STRONG MICRO-CRACKING RESISTANCE AND THE SELF-HEALING POTENTIAL OF THE COMPOSITE STRUCTURE ENABLE THE SYSTEM TO RETAIN HYDROGEN BARRIER PERFORMANCE EVEN AFTER MECHANICAL DAMAGE. THE COATING WILL HAVE TECHNICAL PERFORMANCE TARGETS RELATED TO FRACTURE RESISTANCE, TEARING MODULUS, REDUCTION OF FATIGUE CRACK GROWTH, H-PERMEABILITY RESISTANCE COMPARED TO SINGLE-LAYER COATINGS, AND MAINTAINING THE LIFETIME OF A TYPICAL PIPELINE. THE PROPOSED TECHNOLOGY WILL RESULT IN A REHABILITATION SOLUTION FOR EXISTING STEEL PIPES FOR GAS TRANSMISSION OWNERS/OPERATORS THAT PROVIDES STRUCTURAL SUPPORT TO WITHSTAND MECHANICAL LOAD AND A PROTECTIVE LAYER TO PREVENT HYDROGEN EMBRITTLEMENT. THIS SOLUTION HAS A SUBSTANTIAL VALUE PROPOSITION AS A COST-EFFECTIVE ALTERNATIVE TO DIGGING OUT AND REPLACING OLD PIPES AND HELPS PREPARE THE GAS INFRASTRUCTURE FOR HIGHER HYDROGEN CONTENT IF THE GAS INDUSTRY PURSUES THIS DECARBONIZATION PATHWAY.