Feasibility Journey - Repurposing Existing Natural Gas Pipelines to Transport Hydrogen – Natural Gas Blends

Abstract

Transformation and decarbonization of existing energy systems are a key part of global energy transition efforts to meet targets set in the COP21 Paris Agreement. The feasibility of transitioning existing natural gas networks to hydrogen or hydrogen-natural gas (H2 – NG) blends, is being evaluated by many natural gas operators as part of their decarbonization strategy. It is recognized that the transportation of hydrogen or blended hydrogen and natural gas presents potential challenges that should be considered and assessed before exposing an existing system to hydrogen transport. One of the first steps in such assessment is conducting a high-level study of the existing network feasibility for the transitioning purpose. Such high-level studies include the material and equipment compatibility of the network with H2 to determine an acceptable range of H2 concentration (H2%) that could safely be added to the blend with modest levels of investment and system modifications. The network feasibility is investigated from different aspects including material integrity, equipment accuracy and functionality, chemical compatibility, end use as well as storage and handling. A thorough feasibility study assesses the entirety of the gas supply value chain, from injection to end-use compatibility and is based upon the operator’s hydrogen strategy and roadmap, which details the network capacity of handling hydrogen safely with a detail of necessary modifications. This paper provides an overview of the factors that should be considered throughout a hydrogen feasibility assessment and addresses additional aspects of the overall hydrogen journey that may be evaluated along the way.