2.0 The Proposal
Detailed descriptions of the various components of the proposal are presented in the draft EIS and Section I of the Supplement. The following is a short summary of the proposal description.
2.1 Objectives of the proposal
The objectives of the proposal are to process the gas reserves from the Bayu Undan field into high quality LNG and produce revenue from the export and sale of the product, under operating and environmental conditions as specified by relevant supervising authorities, utilising "Best Practice" technology.
2.2 Alternatives to the proposal
The proponent considered various options and alternatives to the proposal, including:
- a no development option;
- an offshore LNG plant;
- alternative sites for the plant including locations in Indonesia and Australia;
- pipeline route alternatives;
- access road alternatives;
- loading facility alternatives; and
- LNG processing alternatives.
An alternatives analysis was conducted and the preferred site, pipeline route and processing methods determined.
2.3 Subsea pipeline
The 500 km pipeline follows a route from the Bayu-Undan field across the continental shelf through Darwin Harbour and terminates at the LNG plant on Wickham Point. The pipeline will be constructed offshore on a laybarge and installed on the seabed in a continuous operation as the laybarge moves forward. It will be stabilised and protected by a thick concrete weight coating and rock armour where necessary. Rock armour will be used to protect the pipeline along the whole route within Darwin Harbour. At the shore crossing the pipe will be laid within a beach storm bund constructed from armoured rock fill.
2.4 Access road
Access to the LNG plant will be by a 12 metre wide sealed road from the Channel Island road. Construction of the access road will be the responsibility of the NT Government.
2.5 LNG plant
The major components of the LNG plant will be:
- gas processing facilities to refine and refrigerate the natural gas;
- product storage tanks;
- plant infrastructure and utilities;
- a loading jetty on the west side of Wickham Point to transfer the gas to tankers for export; and
- a construction dock on the north-east side of Wickham Point for transfer of building materials, process modules and heavy equipment.
The project will comprise two phases, the construction phase which is expected to take about 3.5 years and the operational phase, estimated to be in the order of 20 - 25 years (with extension subject to discovery of further reserves of natural gas).
The LNG plant has been designed to produce 3 million tonnes per annum (MTPA). Possible future expansion would incorporate a 3 train process, increasing LNG output to 9 MTPA.
Production of LNG will involve removal of hydrocarbon liquids from the feed gas, treatment of the gas to remove carbon dioxide, water and other impurities, liquefaction of the gas and storage prior to loading on to tankers for export.
Approximately 68 ha will be cleared to accommodate the plant facilities (Figure 3 shows the major components). Expansion of the plant would require an additional 32 ha.
The 1.6 km loading jetty will be constructed partly as an armoured rock groyne and partly as an open piled trestle structure. A small ridge within the turning basin (150,000 m3) will be dredged to allow access to and from the loading jetty at all tides. The earth and armour rock construction dock will be built on an intertidal pavement. The approach to the construction dock will require dredging of approximately 50,000 m3 of marine sediments.
Export will require one LNG vessel per week. In addition, loading of other products (LPG, condensate) will occur approximately every fortnight.