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Energy efficiency and sustainability have dominated the global news agenda for the last 18 months, with countries such as the U.K. setting ambitious goals to become net zero by 2050.
While the transition to renewable energy sources such as wind and solar is essential to achieve these objectives, there is still a clear need for oil and gas. This has been demonstrated by the recent global gas shortage, resulting in significant impacts on transport and fuel prices.

There are several elements that are crucial to the energy industry reducing its carbon footprint and one key phase is evaluating the power management systems of existing assets to ensure energy efficiency improvements are identified and implemented. By reducing fuel consumption, oil and gas installations and offshore assets can support net-zero goals and deliver greater efficiencies for rig owners and operators. 

Assessing power management for fuel reduction  

As oil and gas exploration continues to move into deeper waters, the use of Dynamically Positioned (DP) rigs has increased. Using a power plant, DP vessels host a number of thrusters throughout the vessel which allow it to maintain the asset’s position from every direction, no matter the wind or sea state. 

Generally, DP drilling rigs operate in a split-bus or open-bus configuration, with the power management switchboards operating as silos. A typical configuration will have all the breakers between the switchboards with each operating independently. This is the most fault tolerant option to ensure malfunctions on one switchboard are not automatically transferred between the systems. While this delivers greater asset assurance, operating in split-bus configuration results in more engines online than may be required for the total operational loads. Therefore, the engines are not working as efficiently as intended and can create greater emission output. As rig owners strive to reduce fuel consumption, this option is no longer viewed as the ideal mode of power management.

The application of closed-bus operations is not a new concept. However, as the industry continues to focus on decarbonizing existing assets, there has been a greater emphasis on how rigs can successfully transition to this configuration to deliver a more efficient power management system.

When operating in closed-bus mode, the switchboards are tied together, enabling the power plant to run with less fewer engines and more optimal loads, resulting in a significant reduction in fuel usage.

While this option provides a more efficient power source, it does present assurance threats. With switchboards operating together, and not independently, faults can more easily transfer from one engine room to another. In worst-case scenarios, this can result in overspeed or underfilling, driving the load so much that it pulls power from the engine, creating a blackout. While there is a clear desire from operators to drive energy efficiency goals, operational integrity must be guaranteed in this process. Therefore, investment in technology is essential to allow this change to happen safely and efficiently.

Identifying energy efficiency gains

ADC Energy recently completed a project with a major rig owner to analyze a rig’s current power management system and determine if it could safely and effectively operate in closed-bus configuration. 

As part of the project, Failure Mode and Effects Analysis (FMEA) was conducted to determine if the existing protection system was able to support this transition. As asset assurance is an integral element to consider when evaluating power management systems, it is critical that testing parameters are analyzed to mitigate any risk to the rig.

The project highlighted that moving to closed-bus mode could successfully reduce annual CO₂ emissions by 4,800 tonnes per year—potentially delivering a fuel saving of $620,000 per year—while reducing engine running hours by 20%.

With the number of engines required to be online at one time decreased, the enhancement also provides operators and asset owners with greater maintenance schedule flexibility, which can create potential savings of up to $150,000 per annum. The project clearly demonstrates how operators can utilize specialist inspection providers to advise them through this process to ensure that assets continue to operate securely and efficiently with minimal environmental impact.

Supporting net-zero goals

Existing rigs and vessels are critical components in the energy transition, and it is no secret that by evaluating and implementing system upgrades and adopting new technology, considerable sustainability gains can be garnered. 

However, this change cannot happen overnight. It requires significant investment, combined with backing from classification societies, and as the industry continues to recover from the effects of the Covid-19 pandemic, rig owners and operators balance a tricky tightrope of implementing the technology to support environmental goals at a time when investment in innovation is often not feasible. 

Upgrades that directly address carbon emissions can only be delivered if there is clear demand in tandem with investment. While we are seeing promising signs, action is needed now if we are to achieve net-zero goals. 

Austin Hay serves as director of ADC Energy, a specialist provider of integrated rig inspections, working with some of the largest operators in the world to deliver collaborative assessments to identify potential digital, mechanical, electrical or hydraulic issues which may occur onboard an installation or offshore asset. The business works closely its customers to provide support in the identification of appropriate solutions, applying 30 years’ of science, engineering and practical knowledge to identify cost effective and appropriate solutions to engineering problems.