Developments in the pipeline

David Evans and Graeme Peacock, Tata Steel, UK, discuss some key points regarding the pipeline materials and standards required to assist in a smooth energy transition.

As the world moves forward in the energy transition, the range of solutions to support our future energy needs and questions about how they will be delivered to markets become increasingly more complex.

While the oil and gas sector will continue to have a large say in the future direction of the global energy mix, renewable energy will play an increasingly greater role. This was reaffirmed at the recent COP26 conference in Glasgow alongside national commitments to net zero carbon emission targets.

The contribution made by renewables to UK power has more than doubled since 2014: the country’s target for offshore wind capacity by 2030 is 40 gigawatts (GW), compared to current capacity of 11 GW.1

The use of hydrogen is also expected to feature prominently in future energy provision. The International Energy Agency has stated that the time is right to tap into hydrogen’s potential while UK Government analysis suggests up to 30% of the country’s energy consumption by 2050 could be hydrogen-based. 2, 3

In support of net zero emissions targets, momentum in the carbon capture utilisation and storage (CCUS) sector is increasing. In the UK, the first two CCUS projects have already been approved for development while the Government has committed to increasing to four CCUS clusters by 2030 at the latest, with an ambition to capture 10 million t CO2/year by 2030.4

Almost every aspect of the UK Government’s decarbonisation plan is steel intensive – huge amounts of steel will be needed for renewable energy, low-CO2 transportation, and infrastructure schemes for large-scale hydrogen production and distribution, and carbon capture, usage and storage. It will be needed to build and power electric vehicles of tomorrow, as well as creating sustainable buildings and major infrastructure projects, which will help the nation achieve its net zero goals.

Each of the different pieces in the energy mosaic generates questions around delivery, specifically regarding infrastructure and pipeline provision. How can we ensure the power we need is delivered to the end user in the safest, most environmentally effective and financially efficient way? Furthermore, how can we make our steel and pipe making processes as sustainable as possible?

It’s worthwhile examining some of the key sectors within the energy transition, to consider current trends and to explore what the future pipeline and steel requirements might be in each case.

Higher strength for more challenging applications While many analysts suggest consumption and production of oil and gas will decline in future, there is a widespread recognition that it will continue to have an important role to play well into the middle of this century. However, many of the more accessible reservoirs and easier plays around the world have already been exploited, resulting in the need for operators to venture into more challenging and difficult environments, specifically deeper and colder offshore locations.

Meeting the demands found in these more challenging environments is encouraging operators to consider higher strength, high frequency induction (HFI) pipes with higher toughness and greater wall thickness to withstand the impact of hydrostatic pressure. Traditionally 16 mm pipe has been widely used in subsea applications. However, the trend for greater thickness is inspiring some steel manufacturers to increase their manufacturing limits. Tata Steel, for example, has increased its maximum wall thickness for HFI pipe up to 17.5 mm.

The increased use of HFI in deepwater application is another trend that we are likely to see grow. The use of HFI pipe creates significant advantages compared to seamless pipe, but the key is in the manufacturing process. The tight dimensional control that HFI provides can deliver highly consistent wall thickness and diameter. This is a benefit to lay contractors because consistent dimensions across multiple pipes can help speed up their welding processes. It also has potential advantages for possible future applications where data sharing between the manufacturing and welding processes will assist in streamlining operations. An additional benefit over seamless pipe manufacture is that HFI is manufactured by a less energy intense process, which provides considerable cost advantages.

Maximising hydrogen’s potential Hydrogen is attracting significant interest in the drive to reduce carbon emissions and a vast amount of research is currently underway across various industrial sectors to understand how this resource can be most effectively exploited. A major aspect of this research focuses on what the infrastructure requirements will be for hydrogen and how these can be met. How much new infrastructure will be needed and how much of the existing infrastructure

Figure 1. Tata Steel has increased its maximum wall thickness for HFI pipe to 17.5 mm.

Figure 2. Reel lay line pipe.

Figure 3. Manufacturing HFI pipe at Tata Steel’s 20 in. mill in Hartlepool, UK.

will still be usable is a key consideration. The fact that the existing pipeline network across Europe ranges in age from approximately 100 years old to modern line pipe-type steel adds to the challenge.

One of the main issues with hydrogen for pipelines is embrittlement, where hydrogen diffuses into the metal and weakens it. To reduce the potential and impact of embrittlement on pipes will require a high degree of toughness and wall thickness. Some standards organisations such as the American Society of Mechanical Engineers (ASME) have established design standards with safety factors included for increasing the wall thickness of pipe. However, lack of a complete understanding of the impacts of hydrogen embrittlement on pipelines creates a potential for over conservatism in material selection. More research is required to fully understand hydrogen embrittlement on pipelines and to more fully explore the safety standard issues.

The European Pipeline Research Group, which includes Tata Steel among its members, has commissioned significant research into the requirements, while Tata Steel is currently testing hydrogen embrittlement and fatigue life of its own materials at Swansea University. Within the next two years it is expected the industry will have a more settled view on the effects of hydrogen embrittlement on pipelines.

A carbon copy? Like hydrogen, the methodology for the development of CCUS systems is established but the infrastructure implications are still under consideration. Questions about the use of existing pipelines versus new ones are as relevant for CCUS as for hydrogen but, again, higher toughness is expected to be a requirement for pipes bearing CO2. If old and new systems are to be linked together, it is important for pipeline operators to have access to as much of the old pipeline’s history as possible so that the degree of deterioration can be accurately assessed. Furthermore, different countries have their own regulations and it will be essential for operators to be mindful of these when planning new infrastructure networks.

Another aspect to consider is that the degree of preprocessing experienced by the gas onshore will likely have an influence on the potential for corrosion to be suffered by pipelines transporting it to disused fields offshore.

Winds of change Over half of Tata Steel’s tube products go into structural applications, including offshore wind turbines and the infrastructure associated with them, such as transformer stations. As the offshore wind industry continues to expand, demand for structural products in this sector is only expected to increase.

Avoiding over conservatism There are justifiable concerns and considerations when it comes to selecting pipeline steels, but there are occasions when the comfort of over conservatism is unnecessary and uneconomic. The trend for the over specification of materials in the oil and gas industry is well understood but it doesn’t always make for the most lean and efficient operations. As industry explores the pipeline requirements of other energy sources, there is a concern that the culture of over specification in, for example, wall thickness or test temperatures beyond the already-conservative boundaries set by design standards, may spread into these sectors too. It is right to be cautious but it can be counter-productive to be overly cautious.

The value of early engagement The expansion into unchartered territories – whether that is new pipelines for deepwater oil and gas or a network for hydrogen production and transportation – will not be straightforward for asset owners. It is therefore important for them to call on as much available expertise and support as possible, including the experience of pipeline and steel manufacturers.

Engaging with the supply chain as early as possible in the project design phase can help ensure budgets remain within scope and that the supply chain is able to meet project requirements.

A vital link in the energy transition The future of our energy systems is set to create many challenges but also significant opportunities as we transition from dependence on fossil fuels to more environmentally acceptable sources. Delivering these well established and new energy sources from the point of production to the end user will be one of the most critical components in ensuring national energy stability. Achieving this will require pipelines and networks that are fit for the intended purpose.

References

1. https://www.spglobal.com/platts/en/market-insights/latest-news/energytransition/100421-uk-targets-power-from-100-renewable-sources-by-2035 2. https://www.iea.org/reports/the-future-of-hydrogen 3. https://www.iea.org/reports/the-future-of-hydrogen 4. https://www.gov.uk/government/publications/design-of-the-carboncapture-and-storage-ccs-infrastructure-fund/the-carbon-capture-andstorage-infrastructure-fund-an-update-on-its-design-accessible-webpage