School of Chemical and Physical Sciences

Wind Turbine Research

Brooklyn wind turbine, Wellington

Brooklyn wind turbine, Wellington

We are measuring the performance of micro wind turbines in a gusty urban environment and optimising them for operation at higher than average wind speeds. 

Wind power, as a free source of renewable energy, is becoming increasingly recognised in New Zealand, and around the world large wind farms are becoming an acceptable part of the landscape.

Our work is concerned with micro wind turbines - with a rotor less than 2 m in diameter - that have potential for domestic use. In particular, we are researching the benefits of connecting the turbine to the local power grid instead of using it for battery charging, as is current practice.  

Domestic grid tied micro wind turbines offer these features:

  • smaller rotors can accelerate rapidly to harness the increased power in a wind gust
  • a grid tied turbine can be optimised for high wind speeds, when wind has the most power, whereas average wind speeds are needed for battery charging
  • a direct connection to the household power supply will immediately decrease power bills
  • any unused excess power generated is sold back to the local grid, and can offset costs or become a source of income

Windy Wellington

Overseas studies in the UK and the Netherlands are examining potential returns from these turbines in local environments, but Wellington, New Zealand, is uniquely windy.

Annual average wind speeds are in excess of 20 km/h and many exposed Wellington sites experience gale conditions (wind speeds in excess of 60 km/h) on at least 20 days of the year (based on data from NIWA). The European studies are therefore unlikely to be relevant to Wellington conditions.  

Electricity Generation

A small increase in wind speed results in a significant increase in available energy. Assuming all other variables remain constant, the energy that can be generated increases with the cube of the wind speed.

This is shown in the formula, E α ½ Bv3, where E is the energy available for electricity generation, v is the wind speed and B is the Betz limit - the most energy that can continuously be extracted from wind flowing through a turbine (B=0.593). 

So a turbine that is optimised to operate in high wind speeds will extract more energy overall than a turbine optimised for average wind speeds.

Project Support

This project has been made possible by support from:

More Information

This project has now been completed and no further research in this area is planned at this stage. Please contact the School for more information.