Genesis Energy’s 30-month, $145 million upgrade of the Tekapo Canal will ensure the asset remains a key part of the country’s hydro system for at least another 50 years.
Water flowing through the canal accounts for about 5 per cent of the country’s electricity production by the time it has passed through eight hydro power stations in the Waitaki Valley. Successfully enhancing the seismic resilience of the canal and the numerous bridges that cross it was important for both the country and the economic performance of Genesis.
The project involved relining almost a third of the 25-kilometre canal with a geosynthetic liner, the first such use of the product in New Zealand. Four bridges were strengthened and the upper shoulders of a 1.2 kilometre-long, 45 metre-high embankment at Maryburn were replaced to improve its seismic performance.
Genesis says innovative construction and installation techniques, close scheduling of works and safety by design saw the canal returned to service 18 days ahead of schedule and well within budget.
The work was completed with no lost time injuries nor any injuries requiring medical attention, despite 243,896 man-hours being compressed into two three-month work programmes. More than 500 people were inducted on the site, with a peak workforce of about 300 people from New Zealand and Europe.
Deterioration
The need to repair deteriorating sections of the canal was recognised by previous owner Meridian Energy and Genesis prior to the latter’s purchase of the Tekapo assets in July 2011.
Concerned by the deterioration of a temporary repair at Chainage Point 8.17 – where the canal crosses a culvert – Genesis set itself an 18-month deadline to complete the design, consenting and procurement for the work. At least six principal work streams were progressed in parallel during the project and Genesis received 39 consents for the remediation works.
Genesis awarded CarpiTech the contract for the PVC membrane. The specialised material was customised to the company’s requirements and 7,200 rolls were produced in Italy and Spain. Forty-two hectares of the material was installed over two summers.
Genesis says the unique requirements of the project, the level of pre-planning and the flexibility of all the contracting parties saw new design and installation techniques developed.
Work was started early in each of the two summer programmes to take advantage of good weather, while an innovative mobile conveyer system was developed to lay the liner-covering ballast, reducing truck movements and the risk of damage to the liner, while also improving safety.
Genesis says the work has increased the longevity of the Tekapo generation assets, improved the reliability of the local roading infrastructure, and broadened the skill set of the New Zealand contractors working on the project.
The Energy Project of the Year Award category is sponsored by ITL