Wind and Solar System
The Wind Turbine
In early November, 2009, SkyFarming finished installing a 20kW ReDriven wind turbine on Bouverie Farm, 25km south west of Mt Barker. The rotor diameter was 12m and the tower was 18m high. The tower had a hydraulic ram for lifting and lowering the nacelle. This removed the need for cranes for installation and climbing for maintenance. It is believed to be the first tower like this south of the equator.
It is also believed to be the only grid connected wind plant to be installed in WA in 2009.
The turbine had a direct drive generator and so there was no gearbox. It was controlled by a yaw motor which turned the rotor disk into the wind at low wind speeds and out of it at high speeds. Electricity from the generator was processed by 4 PowerOne inverters which converted the electricity to AC and syncronized output with the grid.
The tower, hydraulics, blades, sensors and generator were made in China. The inverters were Italian PowerOne Aruoras. The transformers were made in Western Australia. The controller and overall design was from Canada (ReDriven).
PV and Cable
This project also included 8kW of photovoltaic panels supplied and installed by Aurelius Consulting. Wiring and installation of the 700m cable and the transformers at either end was by Allect.
This project was possible because 50% of the funding came from a SEDO RREP grant AND that the property has a very high baseload. The farm produces trout and marron, so there are numerous pumps and aerators for the ponds and dams spread across the property including three large pumps that run continuously.
An underground cable was installed to take the output from the turbine to the main load at the fish and marron shed, 700m away.
The wind turbine output was limited to less than 15kW.
Currently, Synergy does NOT pay for exported electricity from businesses nor from renewable energy installations bigger than 5kW, this means the renewable energy plant can only save electricity. The 15kW limit does not lose the project much income because it would be rare that the power required from the farm is bigger than this. This 15kW restriction also lowered the cost of the cabling and associated transformers.
Had a Feed In Tariff been available, the full output from the wind turbine could have been utilised and the cost of the new transmission to the shed saved as there is an existing 11kV powerline running above the cable route that could have otherwise been used.
2012 and 2013
Unfortunately, over the following two years, the turbine was extremely unreliable and there were numerous issues including cracking at the blade roots. It also appeared that the wind resource was not that good.
A decision was made early 2012 to turn the electricals off and leave the turbine lying on the ground until a replacement nacelle and blades turned up from the manufacturer. Less than 3 months later, SkyFarming discovered that ReDriven had become bankrupt.
With the price of PV at record lows during 2013, the decision was made to formally decommission the electrical works to the turbine. As the PV panels, in stark contrast to the ReDriven wind turbine, had been producing above expectations, Aurelius Consulting installed a further 8kW of PV on the roof of the shed adjacent to the main power pole and switchboard of the property.