Geographically, Antarctica is the windiest, driest, coldest and highest continent in the world, presenting special and unique challenges for any large-scale technological innovations. Australia's Mawson Station is situated 5463km southwest of Hobart on the coast of Antarctica and is now home to the first large-scale wind-diesel power station on the continent.

On 22 August 2001, Powercorp signed a Wind Turbine Development agreement with Australian Antarctic Division (AAD) and took a lead role in the design and project management of Antarctica's first large-scale wind turbine installation, at Australia's Mawson Station.

Powercorp supplied the advanced control system technology that integrates clean power from the wind turbines with the existing diesel generation. The unique control system termed “Intelligent Power System" or IPS is advanced software, developed entirely in Darwin, Australia by the company's engineers. Our engineers designed equipment to withstand extreme weather including wind gusts in excess of 250km/h and temperatures to minus 36°C.

Three specially designed 300kW E-30 wind turbines suitable for the polar conditions were supplied by German company ENERCON GmbH. These machines, with a blade diameter of 30 metres, harness katabatic winds that flow off the ice cap at an average speed of 50km/h. After shipment from Northern Germany, the turbines were transported to Mawson on the icebreaker Polar Bird.

Live site conditions can be viewed at the Australian Antarctic Division website like below.
http://www.aad.gov.au/apps/operations/electrical.asp

The Wind-Diesel Concept

Wind energy is clean, “free” and available whenever the wind blows. Reciprocating diesel alternators are the first choice for reliable, 24/7 electricity supply to communities in remote or off-grid locations. The concept of a wind-diesel power system is to combine the two power sources in a way that makes best use of the advantages of each type of generation.

Consumers want electric power when the wind isn’t blowing, diesel fuel can be expensive when shipped to remote places. A good solution is to run the diesel alternators continuously but substitute a proportion of wind energy when weather conditions are suitable. Total fuel consumption goes down and power remains available at all times.

The key to a successful result is the right equipment and a wind-diesel system controller to select the correct balance of energy sources for any combination of weather conditions and consumer demand. Powercorp has created a fully automatic station management system, IPS Wind-Diesel, to perform this challenging task.

Wind-Diesel at Mawson Station

In designing a wind-diesel system for an Antarctic research station, one of our first tasks was to analyse the annual patterns of energy use and correlate with the potential for wind generation. We needed to decide how many wind turbines were required, where to site them and the optimum height for the towers.

An interesting finding was that heat for the station buildings made up half of the total energy demand. Recovered waste heat from the jacket water and exhaust gases of the diesel alternators is the prime source of building heat.

Substituting wind energy meant lower output from the diesels and less waste heat. We needed a renewable source of heat to make up the difference and the solution was conversion of excess wind energy to thermal energy in a standard electric boiler.

Low cost, reliable energy storage is the holy grail of the renewable energy industry. Many advanced technologies have been trialled including batteries and hydrogen but they remain commercially marginal. At Mawson the building heating loop contains 20 tonnes of water. Water has a high capacity to store heat and we saw an opportunity to use this for energy storage.

We needed a way to control the amount of energy transferred into the heating loop. Traditional methods including switching contactors were considered but there was a big advantage in using very fast analog control to improve stability of the power system.

Stability becomes an important issue in wind-diesel installations, especially in a high-penetration design like Mawson where the installed capacity of the wind turbines is larger than the diesel power station.

The power delivered by a diesel engine is directly influenced by the throttle setting enabling a fast response to load changes. A wind turbine cannot respond in the same way, its energy source the wind is constantly varying, there may be insufficient wind speed or too much wind as a gust passes through.

The wind turbines at Mawson are an advanced design that utilises several strategies to improve its response. It can pitch the blades individually or allow the rotor to change speed, adding or extracting energy from the rotating mass. But there is still a continual variation in the power output of the wind turbines.

A creative solution is to vary the station demand in a way that compensates for periods of excess or shortage in wind generation. Station heating with its large thermal mass can store or release these energy fluctuations while maintaining temperature of the buildings within an acceptable range.

To control the flow of energy into the station heating loop Powercorp engineers designed a Boiler Grid Interface (BGI). This equipment is based on available power electronic technology and sits between the station power grid and the electric boilers. It uses specialised software to monitor the power system and respond within milliseconds to changes in the balance of generation and load.

The BGI is operating satisfactorily at Mawson, adding frequency stability and providing an added advantage of fast load shedding in the event of an unplanned turbine shutdown.