TrustPower's Keith Tempest says the recent grant of renewable carbon credits was the final key making the expansion possible, noting that it has shifted from a "we would like to do when it becomes viable" to a "can do right now." The company had already cleared the resource consents hurdle and had until 2005 to undertake the expansion. It is now looking to have the first of the new turbines operating by the end of the year, with the full additional 55 machines online in May 2004, ready for winter demand.
"We see wind as a tremendous resource, allowing us to reduce hydro generation when the wind blows, thereby conserving water for times of peak demand. The wind continues to blow during periods of low rainfall which means that wind generation, properly matched with hydro generation, has the capability of providing us a much improved ability to get through dry years with greater certainty of supply," says Tempest.
Low rainfall has meant problems for New Zealand electricity supplies and threats of rolling brownouts this winter. This, combined with the earlier than anticipated closure of the Maui gas fields, has seen intense scrutiny of the country's energy options over the past several months.
Some NZ$60 million will be spent on the expansion, the bulk of it going towards the import of another 55 Vestas machines for a total of 103 V47s. TrustPower made the decision to use the same make and model of turbine because of their proven suitability for the site and to realise economies in maintenance and spare parts requirements. One-third of the project's budget will be spent locally in producing the lattice towers and other support operations.
In tandem with the announcement of the Tararua expansion comes the erection of New Zealand's first major locally developed wind turbine. Windflow Technology has erected its pre-production turbine at its Gebbies Pass site near Christchurch. The unit will be used to test and monitor performance of the system, which includes technology developed by Windflow's founder engineer and managing director, Geoff Henderson. "We have designed this wind turbine to be a world beating machine," says Henderson. "The performance of the pre-production unit will prove our design and allow us to make refinements for stage two." Stage two is to see six units produced and the company supply electricity to the Christchurch City Council.