The North Sea has been a hub of activity in the offshore energy industry for decades, but the rate of innovation remains just as strong as ever – with particular focus now on developing technologies that will have a significant impact on reducing greenhouse gas (GHG) emissions over the coming years. And these technologies will not only be effective in reducing the UK’s GHG footprint, but they can also be deployed in energy production locations worldwide, offering huge potential for wider economic as well environmental impact.

The NSTA is focused on the triple targets of energy security, reducing emissions and accelerating the transition to net zero; and government and industry, through the North Sea Transition Deal (NSTD), have agreed staged reductions in emissions on the way to achieving a net zero basin by 2050.

For offshore oil and gas emission reduction, power requirements and gas flaring are the major opportunities for making a difference, so it is no surprise that innovations are being deployed to impact in those areas. Offshore installations typically require tens of megawatts to drive the pumps, compressors and process heating needed to produce oil and gas, and this normally comes from natural gas driven gas turbines. Where gas is in short supply, diesel engines are often used. In either case the ensuing release of CO₂ from these processes causes the most GHG emissions.

One mitigating measure is to install subsea power cables from shore to provide green electrical power from the UK grid. Another is to connect floating offshore wind turbines provided through the Innovation and Targeted Oil and Gas (INTOG) wind leasing round. Both require significant innovation, and industry players are actively seeking solutions to make them feasible and economically viable.

As an example, more than 100 designs for floating offshore wind (FOW) installations currently exist and there is much work going on to find which will be best for specific situations. Maturing this technology and achieving economies of scale while also achieving the NSTD’s overall targets of 50% UK content and 30% local technology are of critical importance for the North Sea. Work done on electrifying oil and gas installations using FOW could deliver crucial insights which will be invaluable for the much larger offshore wind projects being contemplated under ScotWind and other leasing rounds.

Whichever FOW designs are selected, they will require dynamic power cables to link the floating structure to the seabed to carry the electrical power to the oil and gas installation. The demands on these cables are significant, including physical forces generated by wind and waves and high electrical stresses from the transmitted power. Matching the frequency and voltage produced with the needs of the end user and retrofitting large electrical equipment at often congested host facilities all demand careful design and complex brownfield modifications on live, producing facilities.

For some installations, the use of alternative fuels to replace natural gas or diesel could be a viable alternative. The Net Zero Technology Centre (NZTC) is actively progressing such developments. It has recently successfully tested the operation of a gas turbine fuelled by methanol. Other operators are considering the use of hydrotreated vegetable oil (HVO), reported to offer a drop-in replacement for diesel requiring few, if any, modifications to engines. Both options would require reliable supply chains to provide the quantities of green methanol and HVO required.

The North Sea Transition Authority is focused on the triple targets of energy security, reducing emissions and accelerating the transition to net zero.
 

Reducing flaring and flare gas
Flaring natural gas is the second-largest source of GHG emissions. The flare system is essential for safety, but it also includes emissions from operating equipment sometimes on a continuous basis. Steps are being taken by operators to reach a position of zero routine flaring, in line with the World Bank initiative to eliminate all non-emergency flaring by 2030.

A good example of technology being implemented for flare gas recovery is liquid ring compressors. They employ modern hydraulic and mechanical designs to enable handling of the often highly variable gas composition and flow rate. These units offer lower maintenance and three-stage compression at higher efficiency, enabling capture and boosting of gas for export.

Avoiding the introduction of gas into the flare system is another successful strategy, and the use of acoustic detectors to identify passing valves allows targeted repairs to be carried out during planned shutdowns.

Monitoring the combustion efficiency of the flare tip is possible using remote measurements coupled with algorithms from trial sites, allowing flare operation to be adjusted to reduce the quantity of the flare’s uncombusted gas, which has a much higher GHG footprint than CO₂.

As North Sea infrastructure ages, asset inspection is vital. And in this area, there have been major changes with the introduction of drones and robots, often incorporating novel sensor devices, and the application of advanced imaging techniques and digital twins to support offshore asset interactions. Identifying fugitive emissions, monitoring wall thickness at height and performing checks in the splash zone and subsea are all now routine using unmanned devices. Such technology improves the quantity and quality of the gathered information versus what a human can obtain and does it at lower risk, cost and reduced GHG footprint.

Awareness of the technology available to support oil and gas activities is key to selecting and then deploying those that can make a difference. The NSTA’s annual stewardship survey draws information from all operators and includes details of what technologies they are using, what gaps exist and what plans are being progressed to develop new solutions. A full analysis of this data results in the Technology Insights 2023 report, which includes many examples of specific technologies in use.

Sharing experience and raising awareness are crucial parts of the NSTA’s strategy to increase the use of valuable technologies. Work with the Technology Leadership Board shares operators’ challenges and showcases developers’ technologies.  

The views and opinions expressed in this article are strictly those of the author only and are not necessarily given or endorsed by or on behalf of the Energy Institute.

• Further reading: ‘Evolving energy generation in the North Sea’. A 2023 review of the decommissioning plans for the industry – and new exploration licences announced by the government.
• Find out how the emergence of hydrogen and carbon capture schemes, plus more efficient hydrocarbon production, are shaping the North Sea oil and gas sector for the future.