DNV is launching the second phase of H2Pipe, a joint industry project (JIP) aiming to develop a new code for the design, requalification, construction, and operation of offshore pipelines to transport hydrogen, either pure or blended with natural gas. Industry is exploring ways to transport hydrogen as an additive or replacement for natural gas, but current offshore pipeline codes insufficiently address the topic, the standards and assurance body said.
Phase 2 of H2Pipe is planned to start in first-quarter 2023 and last 2 years. It will consist of a comprehensive experimental test program to enhance the understanding of the governing hydrogen embrittlement mechanisms and how hydrogen affects the integrity of the line pipe material. In addition to the experimental test campaign, Phase 2 will also include tasks such as a feasibility level design of offshore hydrogen pipelines and a risk assessment study to look at safety aspects of offshore hydrogen pipelines. DNV expects the primary outcome of Phase 2 of the JIP to be a detailed guideline offering specific guidance for use in design and repurposing of offshore pipelines for hydrogen transport.
DNV started the first phase of H2Pipe in 2021. An initial test program looking into potential degradation of steel pipe mechanical properties was carried out to fill gaps in existing knowledge and explore various test parameters and narrow down the number of variables as preparation for the main test program planned for Phase 2. The first revision of the guideline was delivered to participants the same year.
The guideline is currently at a high level, and more work is needed to develop more specific acceptance criteria, according to DNV. Phase 1 participants included Vallourec SA and Wellspun Corp.
The DNV standard for submarine pipeline systems (DNV-ST-F101) includes hydrogen as a listed transport product, but additional considerations are required to meet the target safety level for an increased use of hydrogen. A special concern in this respect is the potential detrimental influence of hydrogen on resistance to cracking in carbon steels, DNV said, explaining that to support the uptake of hydrogen as an energy carrier, it is imperative to update the standard to a level of design and material requirements that do not compromise pipeline integrity and safety.
DNV’s ‘Hydrogen Forecast to 2050’ anticipates that more than 50% of hydrogen pipelines globally (and as much as 80% in some regions) will be repurposed from existing natural gas pipeline networks, as doing so is expected to cost less than 35% of new builds.
