Detailed Description :

Background :

The Bacton Gas Terminal is located on the east coast of Norfolk, England.

Phillips Petroleum Company United Kingdom Limited (PPCo) operates the Bacton gas terminal in Norfolk. There are currently four main groups of assets with different “owners”. These are: 1) Hewett Facilities; 2) Shared Facilities; 3) Thames Facilities; and 4) LAPS Facilities. The Shared Facilities are essentially owned by the Hewett partners; however, the ‘shared’ concept provides a tool for managing areas where ownership may change.

PPCo, on behalf of these owners, wished to consider options for the decommissioning of the Bacton gas terminal at some time in the future so that appropriate allocation of costs may be made for future liabilities. The aim of this study was to identify the decommissioning liabilities; to prepare a detailed cost to ±15% for decommissioning the facilities and returning the site to green field; and to apportion the costs by owner.

The study was performed by ode, with specialist input and support from Technical Demolition Services Limited on demolition and disposal, and Celtic Technologies Limited on remediation of any contamination of the site.

The study has been performed in four main areas which are parallel but complementary.

These are: Planning; Preparation; Demolition; and Remediation.

Planning

The relevant regulations, statutes, guidance and codes of practice were reviewed. Their impact on decommissioning was assessed, and a compliance plan to meet the relevant requirements drawn up. Environmental Impact Assessments for each of the main activities was also undertaken.

Preparation

A detailed plan was drawn up for purging and decontaminating the terminal facilities. The plan was based on; the recovery the maximum amount of gas and condensate as saleable product; the utilisation of the remaining gas as fuel; and the onsite incineration of residual gas and vapours.

Demolition

A detailed material take-off was prepared at site and this formed the basis of calculation and application of demolition and disposal costs.

Demolition work was carried out in 17 discrete areas. A detailed demolition plan was prepared and costed addressing;

• Hazardous materials;
• Processing equipment;
• Piping, structural, electrical, instrumentation and other bulk materials;
• Buildings, concrete structures, foundations, hard standing and roads;
• Scrap material.

Remediation

Previous SI reports were reviewed together with site geology and hydrogeology. Contamination sources were identified and remediation alternatives assessed. The remediation process considered soil excavation and disposal, and in-situ biopile treatment processes. A ground water remediation strategy was also formulated utilising biophysical treatment of shallow and deeper groundwater.

Overall Costs and Schedule

The overall costs were determined for the four phases, and allocated across to the four owners. A detailed decommissioning schedule was prepared encompassing all activities from initiation of the consents process to completion of site remediation and re-instatement.