Background

Wind Energy Utilisation in Antarctica

In 1902 Captain Robert Falcon Scott docked the Discovery along the Antarctica ice shelf (Anonymous, 2008a). The Discovery housed the very first wind energy conversion system or wind turbine ever to convert Antarctic wind energy to electrical energy. Sadly, the wind turbine was irreparably damaged during a storm as shown in Figure 1 below.


Figure 1a) the wind turbine stationary on the Discovery and b) the wind turbine generator.

At the start of the 21st century the utilisation of wind energy in Antarctica once more became an option. The maturity of technology, the ever increasing fuel prices and global pressure on green house gas emission reduction forced Antarctic stations to reinvestigate the source of energy. For example: In 2002 the Australian station Mawson saw the erection of the first self-claimed Antarctic wind farm. According to Magill (2008) the farm utilises two 330 kWrated wind turbines. The Belgium station Elizabeth utilises a number of small 6 kWrated wind turbines (Rodrigo, 2006). A new German base Neumayer III will deploy three 30 kWrated wind turbines (Enss, 2004). Wind power developments at stations WASA (Henryson and Svensson, 2004), Amundsen-Scott (Wahl, 2007) and Scott (Frye, 2006) are also expected.

SANAE IV diesel generator system

As at most Antarctic stations the SANAE IV base operations are highly dependent on thermal and electrical energy. Its reliable multi diesel-electric generator system converts approximately 300 000 L/a of Special Antarctic Blend (SAB) diesel to the needed energy. The sustainability and economic feasibility of this energy system are currently threatened by its high operation costs and the pressure on the reduction of green house gas emission. Such threats create an ideal climate for utilising sustainable energy conversion systems e.g. wind turbines.

At its core the current SANAE IV base power system consists of a diesel fuelled power generator system. This power system utilises three ADE-Leror and Somer diesel-electric generator sets, shown in Figure 2. Each of these synchronous generators has a rated capacity of 180 kW/220 kVA. The power produced by this system is supplied to a three phase 380 VAC 50 Hz electrical grid which in turn distributes energy to a variety of domestic and scientific equipment.


Figure 2: The SANAE IV diesel-electric generators.

The multi diesel-electric power system is controlled via a series of GENCON II Programmable Logic Controller (PLC) units. These systems perform load matching and maintain grid voltage and frequency fluctuations within the specified limits. Apart from controlling the power system; the overall control system also ensures that the diesel-electric generators are operated on a rotational and load sharing basis.

Wind Energy Programme

Sustainable Energy at SANAE IV

A variety of experimental small wind turbines were erected at former South African Antarctic stations. However, since 2000, the Department of Mechanical and Mechatronic Engineering at Stellenbosch University have performed a number of studies which concern: preliminary investigations into the utilisation of wind and solar renewable energy systems (Teetz et al., 2004, Olivier et al., 2007). With the research completed the long awaited implementation phase has started. Three 20 kWrated horizontal axis wind turbines will be integrated with the SANAE IV diesel fuelled generator system within a period starting from 2009 and ending in 2011. The implementation of this project is managed by the Department of Electrical and Electronic Engineering under the supervision of Prof. Maarten Kamper.

Why small wind turbines?

The cost and system complexities associated with larger wind turbines led to the investigation of utilising a single or a number of small wind turbines i.e. machines with capacities less than 100 kW. Compared to large wind turbines, small wind turbines are more robust and simpler in design.

Integrating small wind turbines (i.e. capacities less than 100 kW) with the SANAE IV diesel-electric generator system will reduce emissions and the risk of fuel spillage possible during ship-to-base fuel transfers. All diesel consumed by the SANAE IV diesel-electric generator system is transported to the station by diesel powered vehicles. This implies that the SANAE IV base operation cost is most sensitive to diesel fuel price variations. The utilisation of small wind turbines will improve the SANAE IV power system economy and autonomy through diesel fuel savings.

Operating and testing small wind turbines at SANAE IV will yield valuable experience. Such technical experience may contribute to the improvement of future Antarctic small wind power and wind-diesel power developments. The technologies and skills emerging from this programme will contribute to the emerging small wind turbine industry in South Africa.


SANAE IV wind turbine specifications

The basic components and specifications of the SANAE IV horizontal axis wind turbines are presented in Figure 3 below.

20 kW wind turbine
 
Hub height [m]		  
12
 
Rotor diameter [m]		  
7.5
 
Rotor power control		  
furling
 
Generator power control 		 
maximum power-point tracking / speed control
 
Yaw system		  
passive, tail vane
 
Rated power [kW]		  
20 at 12.5 m/s
 
Survival wind speed [m/s]		  
70
 
Operational temperature range [°C]		  
-40 to +40
 
Total mass [kg]

(including  tower)

  
1 500
 
Tower type		  
self-supported, tilting lattice
 
Tower base area [m2]		  
1.5 x 1.5
 
Foundation type		  
rock anchored
 
Grid integration		  
back-to-back converter, current controlled
Figure 3: Wind turbine specifications.

References

  1. Anonymous 2008a, The Old Times - Use of the Wind Force: The wind used as driving force for the impulsion of sailboats and the generation of energy from the old times, electronically available: Windmills History [May 2008]
  2. Enss D. 2004, Rebuild and Operation of the Wintering Station Neumayer III and Retrogradation of the Present Neumayer Station II – Comprehensive Environmental Evaluation Draft, Report available at the Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
  3. Frye J.A. 2006, Performance-objective Design of a Wind-Diesel Hybrid Energy System for Scott Base, Antarctica, A Master of Engineering Thesis, University of Canterbury, New-Zealand, electronically available: Frye Thesis [May 2008]
  4. Henryson M. and Svensson M. 2004, Renewable Power for the Swedish Antarctic Station WASA, Master of Science Thesis, Department of Energy Technology, Stockholm, Sweden, electronically available: Renewable Power for Wasa [June 2007]
  5. Magill P. 2008, Mawson: Antarctica's first wind-powered station, An Australian Antarctica Division article, electronically available: AAD website [May 2008]
  6. Olivier J.R. 2006, Technical and Economic Evaluation of the Utilisation of Solar Energy at South Africa’s SANAE IV Base in Antarctica, A Master of Science in Engineering Thesis, Department Mechanical and Mechatronic Engineering, Stellenbosch University, South Africa
  7. Rodrigo J.S., van Beeck J., Corle C., Berte J., Dewilde L. and Cabooter Y. 2006, Wind power in the future Belgian Antarctic station, European Wind Energy conference and exhibition, Athens, Greece
  8. Teetz H.W 2002, Technical and Economic Evaluation of the Utilisation of Wind Energy at the SANAE IV Base in Antarctica, A Master of Science in Engineering Thesis, Department Mechanical and Mechatronic Engineering, Stellenbosch University, South Africa
  9. Wahl M. 2007, Designing an H-rotor type Wind Turbine for Operation on Amundsen-Scott South Pole Station, Master of Science Thesis, Uppsala University, Sweden