National Gas To Reduce Emissions At St. Fergus Gas Terminal

By B. Henry Henderson

Murphy Group (Murphy) has been awarded the engineering, procurement, and construction contract (EPC) for the St. Fergus Gas Terminal (St. Fergus) Medium Combustion Plant Directive (MCPD) Compressor Project. Located on the northeast coast of Scotland, the project provides access to gas from the UK Continental Shelf and Norway, which it feeds into the gas National Transmission System (NTS). St. Fergus regularly supplies 25% to 50% of the country’s natural gas. The main terminal also receives treated gas from three sub-terminals, currently owned by Shell, Ancala, and North Sea Midstream Partners.

The EPC contract encompasses the design, construction, and commissioning of three compressor units. The project includes all associated civil, electrical, control and instrumentation, process, mechanical, and piping work, along with rotating equipment.

Wholly owned and operated by National Gas, the St. Fergus terminal has been in continuous operation for over 40 years and is the highest utilization compressor site on the NTS. It is required to operate 24 hours a day, 365 days a year. Due to its continuous running, the St. Fergus terminal has some of the highest emissions on the NTS.

The compressors at St. Fergus are configured across three operational plants. Plants 1 and 2 contain a mixture of Siemens Avon and RB211 units. Plant 3 contains two electric-driven Siemens variable speed drives.

The project includes building three new units within the existing Plant 1 and Plant 2 location and modifying an existing Avon 1533 unit. St. Fergus currently has five Siemens (formerly Rolls-Royce) Avon gas compressors; three of which are currently operational with plans to return a fourth to operation. These units are not compliant with MCPD’s emissions directive, which requires that its existing compressor fleet must not exceed 150 mg/m³ NOx beginning January 1, 2030.

The site also has two Siemens (formerly Rolls-Royce) RB211 gas compressors. These compressors support the flows from the NSMP sub-terminal. Significant intervention is required to ensure compliance with the legislation and to maintain the required level of capability and network resilience for customers.

“We are delighted to partner with Murphy and their wider supply chain on this critical part of our compressor replacement program, with this work contributing to our business’s wider 2030 emissions reduction commitments,” said Darren Christie, project director at National Gas. “Our St. Fergus terminal is a critical entry point on the NTS and by utilizing our project partners’ skills and expertise we can hope to see successful delivery of this investment. This will ultimately improve the compressor resilience at the site, providing greater energy security and helping reduce compressor emissions as part of the UK’s Net Zero ambitions.”