Meridian Energy Ltd will spend up to $190 million between now and 2016 upgrading power stations in the Waitaki Valley, to generate more electricity with the same amount of water.
Meridian is refurbishing the Benmore power station at a cost of $60 million, a two-year project due to be completed in April next year.
Following that, $20 million will be spent at Aviemore and then between $60 million and $80 million at the 75-year-old Waitaki station, the firstbuilt on the Waitaki River.
The Benmore project is on target and below cost, and will generate more electricity than first envisaged.
It is the first major refurbishment since the Benmore dam and power station was commissioned in May 1965.
The project started at the beginning of 2008 and will be completed on April 14.
Originally estimated at $67 million - building Benmore 45 years ago cost $62 million - the refurbishment is expected to come in at $60 million.
That will increase the power station's output, as well as making sure it is reliable, cost-effective and lasts for generations to come.
In association with the refurbishment, a $30 million project will improve the link from the power station to Trans- power's HVDC link between Benmore through the Cook Strait cable to Haywards.
Transpower has started its $672 million upgrade of the inter-island link, boosting capacity from 700MW to 1000MW in 2012 and eventually 1400MW in 2014.
The Benmore project is part of Meridian's refurbishment programme.
An average of 40 to 50 people have been working upgrading and improving each of the six turbines.
As each one is taken out of commission, five machines continue generating electricity.
The last turbine has been disassembled and is being refurbished before being reassembled early in the new year with a new runner and other equipment.
This will be followed by testing and commissioning.
Benmore will be back in full production on April 14.
However, there will be brief outages over the next two years to connect and commission two new transformers and associated equipment which is part of upgrading the link between the powerhouse and the HVDC line.
Once completed, the turbines will use 5% less water to generate the same amount of electricity.
This will add about 70GWh a year to Benmore's current 2200GWh - enough electricity for up to 8750 homes - through more efficient turbines with the latest technology.
Once the Benmore refurbishment is completed, Meridian will move on to other projects, including the $20 million Aviemore main transformer replacement project next year.
This project is to replace the original transformers, to ensure a further 45-plus years of service and reduce maintenance costs.
The next project is the Waitaki upgrade, costing $60 million to $80 million, between next year and 2016.\
Meridian upgrades
Benmore: $60 million
Aviemore: $20 million
Waitaki: $80 million
Additional spending: $30 million
Total: $190 million
