Industrial gas users north of Taranaki are on short rations after the Maui gas pipeline was closed this morning to investigate reports of a leak in the critical supply line for natural gas to a range of industries, including electricity generators, dairy processors and food processors.
For the moment, all electricity generators north of the pipeline closure, understood to be around Whitecliffs, north of New Plymouth, have been instructed not to use gas-fired generation, but the next tiers of industrial and commercial users have yet to receive any instruction.
National grid operator Transpower advised it "believes there is sufficient alternative generation to cover for the immediate gas outage."
A conference call among gas industry participants was under way at 11am, with potential for further cutbacks being ordered for other major users.
The typical pattern in major gas pipeline outages is for major users to cut back consumption and, if serious enough, to close operations, but for residential gas users to be unaffected in the short term.
The so-called "line-pack" in gas pipelines - quantities of gas that are already in the pipe and under pressure - are able to continue to be used for some days after a major pipeline is closed, with a system of rationing instituted depending on how serious the outage is.
The first rationing step is the one taken this morning to limit electricity generation using gas.
Transpower is working closely with Vector, which manages the pipeline, while the Gas Industry Company (GIC) is dealing with the Critical Contingency protocols and the curtailment of customers.
Further statements are expected shortly, with an update on electricity generation impacts due at 4pm today.