The site near the Manawatu Gorge area is ideal for wind farms. The Tararua and Ruahine Ranges provide a barrier to the predominantly westerly winds that flow across New Zealand. Between the two ranges lies a lower range of hills that serve to funnel the wind. TrustPower, another New Zealand electricity generator and retailer, operates a wind farm on the south side of the Manawatu Gorge.
The Te Apiti wind farm is also a carbon offset project. In 2005 the British bank HSBC purchased 125,000 tonnes worth of carbon credits from Meridian generated by the wind farm. Meridian Energy also sold the Dutch government 530,000 tonnes of carbon credits from Te Apiti. The price per tonne was considered to be about $10.40 a tonne. In both cases, the carbon credits for Te Apiti were from New Zealand’s Assigned amount units allocated under the Kyoto Protocol. The New Zealand Government granted the AAUs to Meridian Energy as an incentive for carbon neutral power development under the Projects to Reduce Emissions programme (or PRE).
As of 2007, installed capacity of wind turbines in New Zealand has reached 321 MW and a further 46.5 MW is under construction.
Te Apiti was the first wind farm in New Zealand to connect directly to Transpower’s national grid. Previously constructed windfarms, including Hau Nui and Tararua, connected to the national grid via local distribution and sub-transmission lines.
Electricity from the 55 turbines is sent via a 48-kilometre (30 mi) network of underground cables to the Te Apiti substation near the lookout, where the electricity is stepped-up to 110 kV for transmission. A 4.5-kilometre (2.8 mi) single-circuit transmission line runs east from the substation, down to the Woodville substation, where electricity generated by Te Apiti is distributed via three 110 kV circuits to the Hawke’s Bay (two circuits) and the Wairarapa (one circuit). An additional twin-circuit line connects Woodville to Bunnythorpe, near Palmerston North, where Te Apiti’s generation is connected to the 220 kV grid for distribution to Wellington, Waikato, and Taranaki.
Virtual field trip
The New Zealand online education programme, LEARNZ, conducted a virtual field trip to Te Apiti Wind Farm in April 2008. Over 1500 New Zealand school students joined LEARNZ teacher Darren on this trip. Telephone conferences were held between students and wind farm staff. Two telephone conferences were held while Darren and Meridian staff were on top of a 70m high wind turbine.