NGC announced the long-awaited agreement today, saying it heralded a new era of open access gas transmission.

The Maui Pipeline Operating Code (MPOC) is to take effect from October and will allow non-Maui gas to be shipped by any party through the onshore Taranaki-Huntly Maui pipeline.

Open access to the country’s largest pipeline is seen as essential for transporting gas from other Taranaki fields north to energy-hungry Auckland and other regions.

Previously, under the Maui contract, only Maui gas molecules were allowed to be transported in the pipeline.

NGC’s interconnection agreement with MDL provides for the seamless transfer of gas between the Maui pipeline and NGC’s gas transmission pipeline servicing the wider North Island.

NGC chief executive Bryan Crawford said the arrangements ushered in a new era of open access gas transportation for New Zealand.

This was necessary to maintain a commercially robust delivery framework as Maui reserves declined and the gas industry increasingly relied on supplies from other fields, he said.

"This significant step for the industry follows the Minister of Energy endorsing the open access arrangements as being consistent with the government’s policy statement for the gas industry, and it will improve the security of supply in both the gas and electricity sectors," Crawford said.

Maui open access would also require major commercial and physical changes to NGC’s own transmission system, including amended commercial arrangements, the upgrading of metering and other systems instrumentation, and the upgrading of NGC’s gas control facilities in New Plymouth, according to Crawford.

There would also need to be pipeline reconfigurations to enable gas from NGC’s gas treatment plant at Kapuni to be transported north and to join the Maui pipeline. Previously this had to be transported in NGC's smaller pipeline.

Maui Development Ltd – owned by the Maui partners Shell NZ, Todd and OMV – have appointed NGC as the system operator for Maui open access. NGC will manage access arrangements for both pipeline systems.

A manual system will be used until a web-based information platform, specifically tailored for open access administration in New Zealand, is commissioned early next year.

"The wind-down of Maui, increasing use of supplies from multiple smaller fields and expected future production from currently undeveloped fields, such as Pohokura and Kupe, introduce complexities for the gas industry, not only in terms of supply sources, but also for transmission system operations,” said Crawford.

"For NGC as systems operator, this has necessitated the development of technically sophisticated information systems to meet requirements, such as daily rather than monthly reconciliations.

"For gas shippers, the new regime requires them to sign the Maui code, and imposes tighter disciplines in forecasting and booking pipeline capacity."

Crawford added that NGC's transmission system had been available for open access transportation for over a decade and that features, such as capacity transfer and trading, would continue.