Gas Supply Disruption
Natural Gas Corporation (NGC) advises it now expects to restore full supplies of gas to the southern half of the North Island by midnight tonight.
However, supply will continue to be very tight and conservation of available linepack (gas still in the pipeline south of the isolated section) is essential.
Last night, NGC established a team of 12 people and equipment at the site near Himatangi, north of Foxton, where yesterday a bulldozer ruptured the 8 inch high pressure gas transmission pipeline which delivers gas to the southern North Island. Gas supplies to Hawke’s Bay, Manawatu, Kapiti/Horowhenua, and the greater Wellington region are severely restricted.
During the night, the site was declared gas-free, the bulldozer was removed from the pipeline easement and excavations carried out to expose a length of the pipeline in preparation for cutting out the damage section. Cutting began at 5.30am today and a new 12-16 metre section of pipe will be installed during the course of the day.
Once installed, welds will be x-rayed to ensure their integrity, the isolated section will be purged of air and any other potential contaminants, and this will be followed by the controlled repressurisation of the southern North Island system.
NGC reported today that gas use was significantly below normal levels, indicating that large users had ceased offtake. Pressure in the system was declining, however, and while NGC remained hopeful linepack would be sufficient to continue to meet the needs of domestic customers and essential services, it appealed to the customers to use gas sparingly and avoid unnecessary usage.
Gas offtake during this morning’s peak usage period would be a key to the ability to maintain supply from linepack during the period of supply restriction. Offtake and system pressures are under continuous monitoring, and NGC will continue to keep retailers informed of the supply/demand position.
NGC said the pipeline rupture resulted in no significant injuries or public health risks.