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Pathways to decarbonisation

Janka O’Brien, Director of Sustainability, MEA, Emerson Automation Solutions, UAE, considers opportunities to store, transport and distribute hydrogen.

The oil and gas industry are going through a massive transformation towards sustainability and decarbonisation. While we see several initiatives at play towards more sustainable operational practices by operators and oil and gas end users, there continues to be much to do in order to meet net-zero targets.

Even with the emergence of newer energy sources such as solar and wind, there is consensus that the molecule form of energy is here to stay – we are transitioning from coal to oil to natural gas as the primary drivers of global energy, and are approaching the beginning of a new wave of energy through emerging value chains such as hydrogen.

The emissions problem As operators look for opportunities to progress their sustainability journeys – the focus shifts to oil and gas pipelines. Much of traditional emissions measurement and reduction focus has been around the operating plant, yet oil and gas pipelines have one of the highest methane emissions profiles across the value chain – not just with oil pipelines, but also with gas pipelines. This is an interesting situation, as gas is broadly seen as a ‘cleaner’ fossil fuel and a transition fuel as the world shifts to net-zero. In fact, across the natural gas value chain, pipeline transport is a key source of emissions, especially for older pipelines and networks. To add context and scale to this problem – it is estimated that the global length of oil and gas pipelines transportation networks is approximately 1.8 million km long, enough to circle the earth 30 times over.

Roadmap towards emissions reduction First and foremost, pipeline operators must have quantified emissions reductions targets; according to a DNV survey that was conducted across global pipeline operators, as many as 63% have quantified goals around reducing emissions by at least 50% by 2050.

From here, an operational roadmap towards emissions reduction can begin with the low hanging fruit:

Fugitive emissions and leaks through flanges, valves and packaging material. Regular inspection, maintenance and upgradation of packing material to minimise leaks are key routes to reducing emissions.

Many gas pipelines still utilise gas operated valves, which vent gas to the atmosphere. There are several ways to address this; these valve operators can be upgraded to reduce bleed, modified to operate on instrument air (via volume tanks) or to return gas back into the pipelines or to electric actuators altogether. This reduces emissions on a per-use basis and can make a sizeable dent on emissions over the lifetime of the pipeline.

Similarly, optimal leak detection systems across transmission pipelines also holds promise of reducing greenhouse gas emissions, particularly in the case of gas pipelines, through early identification that can prompt remedial approaches. There are several technology approaches to leak detection that range from real-time detection, periodic surveys to computational and real-time model-based systems that can be deployed.

Finally, vapour recovery systems can be utilised to recover light hydrocarbons or gases from liquids that are removed by pigging operations. Gases rich in hydrocarbons tend to condense liquids in gathering systems upstream of gas gathering and processing plants. These pipelines are periodically pigged, and condensate is removed and moved to a lowpressure storage tank. The liquids during recovery flash and vent light hydrocarbon gases from the storage tanks – vapour recovery systems can both reduce emissions, but also improve pipeline throughput.

A broader look at energy use As pipeline operations build momentum around the use of operational technology to reduce emissions, operators must take a holistic view of the energy use of the entire pipeline. Good examples of these are compressors and pumping systems, which are key equipment that ensure the efficient functioning of the pipeline. The right asset performance and condition monitoring programme can help compressors and pumps run most efficiently, and therefore consume the lowest energy to operate.

Hydrogen: the transformative opportunity Hydrogen is a very versatile fuel that has a variety of use cases, from transportation to heating to long-term energy storage and can serve as an energy vector to other green chemicals such as ammonia and methanol. The global opportunity for green hydrogen is expected to be worth US$11 trillion by 2050, according to Goldman Sachs.

Despite the opportunity, one of the key barriers to success lies in the lack of dedicated infrastructure to store, transport and distribute hydrogen. Building new transport infrastructure depends on detailed planning and approvals which are both time and cost sensitive.

Here, existing gas pipeline networks are now being seen as a potential substitute to building new hydrogen pipeline infrastructure. In order to repurpose existing pipeline infrastructure, it needs to be re-assessed for readiness and there would be potential modifications the existing pipeline design. For example, compressor requirements for hydrogen transport will be quite different to traditional gas transport. Similarly, some metal pipes can degrade when they are exposed to hydrogen over long periods, particularly with hydrogen in high concentrations and at high pressures. This effect is highly dependant on the type of steel and must be assessed on a case-by-case basis. Emerson has non-intrusive corrosion sensors that can be deployed to test the integrity of existing gas pipeline networks while transporting hydrogen.

Another opportunity that is relatively quick to deploy and is seeing large traction globally, is the blending of hydrogen with existing natural gas to create a blend with relatively high calorific value but a smaller emissions footprint when compared to pure natural gas. Several countries in the EU allow for between 2 - 6% of hydrogen to be blended with natural gas. Emerson is working with customers to provide fully integrated solutions that help in the blending of hydrogen into existing natural gas transmission networks. These consist of gas chromatographs to measure the purity of the hydrogen being blended, Coriolis meters to measure the quantity of the hydrogen being injected, and Fisher control valves to carefully tune the hydrogen blend.

Conclusion There are several approaches to sustainability and decarbonisation across existing transmission pipelines: from solutions that help reduce emissions to transformative opportunities such as hydrogen transport and hydrogen blending, Emerson is working with customers to take incremental steps towards emissions reduction and sustainability, and navigate the transition towards a future hydrogen economy.

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