About CATS
Accordion Arrow

The Central Area Transmission System (CATS) is a gas transportation and processing system that transports gas from the Central North Sea to a terminal at Teesside in the North East of England.

CATS currently serves over 30 producing fields connected via a series of production hubs, and in 2020 delivered nearly 9 billion cubic metres of gas to UK markets.

CATS started operating in 1993. The project comprising the offshore riser platform and the pipeline, was completed on time and within budget. Together with the development of the Everest and Lomond fields, it was one of the largest construction projects ever undertaken in the UK, second only to the Channel Tunnel at that time.

Due to increased demand within the Central North Sea, the decision was taken to provide a processing service to future users of the CATS pipeline, enabling delivery of their gas into the National Transmission System.

Cats map

This required the construction of a pipeline reception and gas treatment facility, and the CATS gas and liquids processing plant, comprising two processing trains each with the capacity to handle around 17 million standard cubic metres (600 million standard cubic feet) of gas per day.

The first of the new trains went into operation in May 1997, and the second train started up in February 1998.

Since its inception, CATS has been operating safely and successfully. It has a first-class safety and operational record and a well-deserved reputation for being a safe and reliable transportation route for gas fields in the Central North Sea.

Key Stats

Started operating in 1993

Serves over 30 producing fields

In 2020 delivered nearly 9 billion standard cubic metres of gas to UK markets

Carbon intensity reduced by 26% over last 5 years

19 years LTI free (Jan 2021)

Safety critical and maintenance backlogs are consistently at zero hours

CATS pipeline has the capacity to transport up to 48 million standard cubic metres of gas per day

CATS gas processing capacity of 34 million standard cubic metres of gas per day

Two gas processing trains each with capacity of 17 million standard cubic metres of gas per day

Infrastructure
Accordion Arrow

CATS riser platform

The CATS riser platform (CRP) is located at the north end of the CATS pipeline, in Block 22/10a of the Central North Sea and is bridge-linked to the North Everest platform.

The CRP gathers natural gas and condensate from a number of fields. The incoming gas and condensate is aggregated on the the CRP.

CATS Riser Platform
CATS Riser Platform linked to North Everest Platform

From the CRP, the gas is transported via the CATS pipeline to the CATS terminal on Teesside, and condensate is exported via the (not-CATS owned) Everest Liquid System which connects into the Forties Pipeline System.


CATS pipeline

The 36 inch diameter CATS pipeline runs along the seabed from the riser platform to landfall at Coatham Sands, Teesside – a distance of 396 kilometres (246 miles).

From this point, the line runs via a Beach Valve Station to the CATS terminal at Seal Sands, 7.8 kilometres (5 miles) away.

The outside of the pipe is coated in concrete which gives added protection and ensures it remains firmly on the ocean bed while the gas is in transit. The inside of the pipe is lined with an epoxy film, which reduces friction and corrosion, thus maximising its capacity and prolonging the life of the pipeline.

There are six connection points, known as ‘tees’, spaced at intervals along the pipeline. Customers can connect directly to CATS at any one of these subsea tees or at the riser platform.

Customers can also connect to CATS via one of the existing hubs (Andrew, Armada, Banff, Culzean, ETAP, Everest, Huntington, J- Block, Lomond, MonArb, Stella), subject to agreeing terms and conditions with the hub owners.

Connections can be made while gas is flowing which means CATS can provide an uninterrupted service for existing customers while accommodating those who are connecting to CATS for the first time.

CATS pipeline

CATS Pipeline

CATS pipeline is 404 kilometres long from the CATS riser platform to the CATS terminal in North East of England

Pipeline is 36 inch diameter

Capacity to flow 48 million standard cubic metres of gas per day

Connection points available subsea via 6 installed tees

Connection points available at the CATS riser platform

11 existing offshore platforms/hubs connect into the CATS pipeline

Consistently achieves an annual pipeline availability in excess of 99.9%


CATS terminal

The CATS terminal on Teesside is situated within a 29-hectare (72 acre) site.

The terminal reception facilities measure (to fiscal standard) and remove contaminants (eg particulate, hydrogen sulphide, and mercury) from all incoming gas received via the CATS pipeline.

The treated gas is then metered and routed to either the CATS gas processing plant, or to the adjacent Teesside Gas Processing Plant (TGPP) as determined by each Shipper's contractual arrangements.

The CATS gas processing plant on the CATS terminal comprises two gas processing trains, each with capacity of around 17-million standard cubic metres (600-million standard cubic feet) per day.

CATS delivers gas directly into the National Transmission System, with liquid products (propane, butane, and a mixed condensate C5+ stream) exported via pipelines to nearby third-party facilities for sale or storage and loading.

The terminal is manned 24 hours a day, 365 days a year, and consistently achieves an annual terminal availability in excess of 99.5%, as well as an excellent safety and environmental record.

CATS terminal in daylight
CATS terminal in Teesside

CATS Terminal

29-hectare site located on Teesside, in England

A gas reception facility capable of treating up to 48 million standard cubic metres of gas per day

CATS gas processing capacity of 34 million standard cubic metres of gas per day

Two gas processing trains each with capacity of 17 million standard cubic metres of gas per day

Sales gas exported directly into UK National Transmission System

Natural gas liquid products exported via pipeline to local downstream industry and storage facilities

Customers
Accordion Arrow

Most of the major North Sea gas producers are CATS customers.

Independent, global and national operators are using CATS as a safe and reliable route for the transportation and processing of their gas.

CATS currently serves more than 30 producing fields, connected via a series of production hubs.


Secure Customer Site

CATS customers have access to a Secure Customer Site, which gives them the capability and information required to manage their gas sales in the increasingly competitive and complex UK market.

Customers submit nominations for gas redelivery and receive near real-time information regarding gas flows through CATS, including:

  • Gas inputs into the CATS pipeline
  • Stock held within the CATS pipeline
  • Current nominations at each gas redelivery point
  • Gas quantities redelivered to the National Transmission System or elsewhere
  • Quantities of propane, butane and condensate redelivered

In addition, the site provides important operational information and access to historical data covering the previous three years.

Ownership, Operatorship & Partnerships
Accordion Arrow

Kellas Midstream's owners, BlackRock and GIC, are the majority owners of CATS.

Other partners with equity in CATS are Eni (0.3388 per cent) and Harbour Energy (0.6630 per cent).

BlackRock and GIC own their 99% stake in CATS via Kellas Midstream Limited, which is accountable for the strategy, operational and financial performance, along with growing the business. Kellas Midstream Limited owns CATS North Sea Limited, the Operator of CATS under the CATS Parties Joint Venture.

CATS North Sea Limited appointed Wood as its operating partner, introducing a novel operating model focused on a long-term strategic relationship. Wood provides the resources to manage day-to-day operation of the CATS terminal and pipeline.

Harbour Energy, as operator of the North Everest platform, is duty holder of the CATS riser platform. The North Everest platform is bridge-linked to the CATS riser platform.

OWNERSHIP, OPERATORSHIP & PARTNERSHIPS

Operator: CATS North Sea Limited (wholly owned by Kellas Midstream)

Owners (equity): Kellas Midstream (98.9982%), Harbour Energy (0.6630%), Eni (0.3388%)

Operating Partners: Wood (CATS terminal and pipeline), Harbour Energy (CATS riser platform)

Information for Customers
Accordion Arrow
Technical Documents
Accordion Arrow

CATS System Technical Overview

Diagram 1 CATS System

Diagram 2 CATS Offshore Riser Platform

Diagram 3 CATS Terminal

Working near the CATS Infrastructure
Accordion Arrow

Kellas Midstream, with operating partner Wood, is committed to managing the Central Area Transmission System (CATS) safely and responsibly.

Ensuring the integrity and safety of CATS is the top priority and, if you are planning to work near the CATS pipeline, it is essential you follow the steps below, prior to any work starting:

These steps will help everyone stay safe when operating near the CATS pipeline.

CATS Pipeline Emergency Contacts
Accordion Arrow

To report a pipeline emergency please call +44 (0)1642 546404 and ask for the Operations team.