From a practical perspective, New Zealand has abundant wind resources and an extensive 11 kV rural distribution lines network. Distributed wind generations aims to utilize the wind resources available and the existing lines system. Distributed wind farms are generally small (0.1-5MW) and utilize a small number (2-5) of modestly sized (up to 50m hub height) turbines.
There are a number of manufacturers globally who produce such turbines; although the largest manufacturers have been increasing turbine sizes (up to 5 MW on 100m towers) as technology has improved. None the less, there are still some manufacturers who produce small commercial turbines (0.25-0.75MW)
New versus Reconditioned Turbines
It would be easier to use new turbines in every circumstance. However, when considering small distributed wind farm developments in fiscal jurisdictions where Government assistance is not present, the cost of new turbines is often prohibitive. This is because economies of scale are not available for smaller scale projects, or wind resources may not sufficient to deliver commercial investment returns to the investors.
To ensure these sitescan be developed, of which there are many in New Zealand close to existing lines, Energy3 has relationships with suppliers of second hand turbines from Europe. These turbines become available as existing wind farm owners in Europe repower their wind farms with bigger and more advanced turbines (to increase energy yield). Typically, these turbines have 5-10 years service (from a design life of 20 years). The capital cost of second hand turbines is less than half of a new turbine, while the operating life of the turbines can be extended with professional reconditioning of major rotating parts and consumable items such as mountings and brakes prior to re installation.
Energy3 has reviewed turbine manufacturers globally who produce suitable turbines for distributed wind farms in New Zealand. Our criteria for selection are:
- Compatibility with the New Zealand grid - 50Hz
- Well proven technology and standardization of manufacturing components
- Ease of installation without the requirement for special access provisions or heavy duty cranes
- Reasonable availability and delivery timeframes
Energy3 has discussed the supply of many different types and sizes of turbines with European wind farm developers. Our criteria for selection are:
- Compatibility with New Zealand grid - 50Hz
- Second hand machines are supplied with a full service history
- Certified by a engineer
- Reconditioned prior to installation
Where possible, we aim to source turbines which can be shipped in a 40 foot container to minimize transport costs (hub diameter 20m typically). Our focus is on turbines from 100kW to 600 kW Ð such as a Vestas V42 (pitch control) or Micon 530 (stall control).