North bank scheme feasibility investigated

Meridian Energy Ltd is preparing for a major engineering feasibility study into its proposed Waitaki River north bank tunnel power scheme to finalise the design, derive an up-to-date costing and determine its commercial viability.

A consortium led by Aecom, a professional services company with offices in more than 100 countries, was selected to undertake the two-stage study.

It has begun preparatory work already.

Carrying out the full study will depend on issues such as a decision from the Environment Court on whether water should be granted for the scheme, a 34km-long tunnel with a single power house between the Waitaki dam and the Stonewall, near Ikawai.

There are two options for the power house: underground near the Waitaki dam or above ground at the outfall.

The study's first stage will look at the viability and economics of the project, identify a preferred layout and pursue land-use resource-consent applications with the Waimate District Council.

The decision to proceed with the study's second stage will be dependent on the Environment Court's decision and the viability and economics of the project determined during stage 1.

If stage 2 goes ahead, it will include further investigation, an update of cost and risk estimates, and design completion.

The feasibility study is one step in the timetable Meridian has for the scheme, which could see it completed by 2020.

External relations manager Clare Shaw yesterday said the study would provide Meridian Energy with a clearer view of the commercial viability of the north bank scheme.

The information would be used by Meridian managers and the board of directors to decide if and when to proceed with detailed design and construction work.

The study would also provide information for the application for land-use resource consents to build and operate the scheme.

Expressions of interest in carrying out the study were called in February and the consortium was now carrying out initial planning and preparation, she said.

Those processes included some limited drilling and preliminary engineering design work.

"If and when we commit to a full engineering study, this will involve more extensive investigations and design work, likely to take 12 to 14 months," she said.

Some design work and estimates of the cost of the scheme were carried out by Meridian in a pre-feasibility study to prepare for resource-consent applications to take water from the lower Waitaki River.

Meridian made it clear the water-only consents, granted in December by Environment Canterbury but appealed to the Environment Court, were just one step in the process of deciding whether to build the scheme.