Aerogenesis is a new company that is commercialising the small wind turbine technology developed at the University of Newcastle over many years. The company’s first product is a two-bladed 5 kilowatt (kW) wind turbine. Mr Wood said the wind turbine incorporates a number of major technological advances.

Tech talk

The turbine is unusual in a number of ways. Production cost and complexity have been reduced by using standard, mass-produced components for the gearbox, generator and brake units at the heart of the turbine and the motor speed controllers. The motor speed controllers are designed by Zener Electric in Sydney as the basis for the controller/inverter. Integration of the inverter with the control electronics allows direct grid connection without the owner having to purchase a separate inverter.

The three phase power generated by the turbine varies in frequency as the blade speed changes to match the wind speed. It is immediately rectified to a constant voltage and then inverted to produce 220 volt, 50 hertz AC single phase output voltage whatever the wind speed. This process is controlled by a microprocessor that also tracks the maximum power producing characteristic of the blades for most operating conditions but then deliberately slows down the blades at high wind speeds to avoid excessive power. This is the primary method of over-speed protection.

Combined with a stand-alone tower that avoids the guy-wires used by many small turbines, and the low cost, Mr Wood said “The turbine is very attractive for installation in urban wind farms or ‘wind hubs’ as we call them.”

Location, location, location

Mr Wood said that at a good site, one with an average wind speed of 5 metres per second (m/s), the turbine will produce about 23 kW hours per day at a unit cost much lower than that of a 5 kW photovoltaic (PV) array. However, it is not as easy to find good sites for wind as it is for solar photovoltaic systems.

The wind resource is much more localised and can vary significantly over a distance measured in metres. Wind monitoring over a sufficient period to establish the resource – typically one year – can cost a large proportion of the cost of a turbine. Much of the wind speed and direction data that is available for urban areas comes from the Bureau of Meteorology or the New South Wales Department of Environment and Climate Change. Most of this data is measured at a height of 10 metres and there are many pitfalls in extrapolating to a hub height of 18 metres. Mr Wood said that the company is looking at a number of ways of addressing this problem, including computer modelling of air flows.

Supporting the urban wind industry

“The current high cost of small-scale renewable energy is a major driver for feed-in tariff (FIT) legislation in force in Queensland, Victoria, South Australia and the ACT, with NSW likely to follow this year,” said Mr Wood.

Under a FIT, small-scale producers are guaranteed a premium on the electricity they produce, which may be four times the base rate. Unfortunately only the ACT legislation includes wind energy, however Mr Wood said the company is working hard to remedy this deficiency in the other jurisdictions. In his view FITs should reduce significantly over time as industry develops and small renewable technologies become competitive with other forms of generation.

The initial development of the turbine is being supported by a grant of $495,000 from the Australian Greenhouse Office in order to install three turbines in Australia and two in China for testing. The company will also receive $750,000 from the New South Wales Renewable Energy Development Program (REDP) to subsidise the installation of 40 of the 5 kW turbines.

The REDP project will also support the development of mass manufacturing; the blades will be made by a large composites company in China and the controller/inverters assembled at Zener’s factory in Taiwan. Mr Wood explained that this decision is based upon the wider context of the business and the current high costs of all small-scale renewable technology.

Aerogenesis is negotiating for major projects in India, Bangladesh, and Kenya where the use of local manufacture to reduce costs and aid development is a major attraction of the product.

A windy future

Beginning next year, the company plans to expand its product range with a 30 kW turbine to be followed by ones up to around 150 kW. The turbine technology scales up easily to around 400 kW with significant cost reduction. These larger turbines are suitable for island power systems, remote mini-grids, and tourist resorts, as well as larger wind hubs.