In the pursuit of Net Carbon Zero Emission (NZCE), PETRONAS pipeline engineering is exploring the feasibility of blending hydrogen into Malaysia’s existing prime natural gas transmission pipeline network to reduce the CO₂ emission from power generation. The main objectives are to address technical barriers especially in the aspect of blending ratio, materials compatibility, techno-economic analysis, and life cycle analysis that will define the development concept that characterize the opportunities, costs, and risks of blending.

Hydrogen atom is known to be the smallest atom, capable of diffusing into various engineering materials including polymers and metals. Under the right condition, hydrogen atoms are capable to diffuse into polymer materials up to their saturation level and cause swelling. Then, when the pressure is released (e.g. hydrogen is consumed or transferred), it causes supersaturation in the polymer. On the other hand, when metal is exposed to hydrogen-rich environment, the atom is likely to segregate within the metal crystal lattice, weaking it chemical bonds leading to a failure commonly known as hydrogen embrittlement. These scenarios are mentioned in various standards and literatures related to hydrogen storage and transportation facilities which exposed to very high level of hydrogen. However, reference on exposure to small level of hydrogen is not available or hardly found in public domain, in which full understanding on the matter might be a key enabler in this decarbonization effort, especially when dealing with existing pipeline network.

This paper presents a compatibility study of existing sales gas transmission pipeline facilities to accept hydrogen added into the natural gas composition. All components exposed to hydrogen blended natural gas would be reviewed including linepipes, bends, valves, fittings, and gas turbine compressor. Besides these aims, this study also determined suitable injection location, recommended hydrogen percentage as well as the need for testing as to ascertain future replication.