Mapping the wind

Wind_Atlas_SA_hovedbillede.ashxA picture from Google Earth is a colorful carpet that shows where to erect wind turbines and where not toSouth Africa is the 30th place in the world to have a detailed map of the country’s wind resources thanks to Risø DTU, Denmark's National laboratory for Sustainable Energy. The map shows the best locations for wind turbines and is a prerequisite for funding wind farms.


The maps are produced by means of extensive measurements and software programs developed in the Wind Energy Division at Risø DTU. Similar maps are now used in 30 countries around the world, e.g. in Ireland, India, the Faroe Islands, Egypt and China. Right now a map is being prepared for South Africa.
It may look simple, but in order to have an illustrative map, you have to do measurements and model the wind conditions in the area. Senior Scientist Andrea Hahmann says, "The project began last year when we went to South Africa to find the right partners. We got to know various scientists from the University of Cape Town, the Council for Scientific and Industrial Research (CSIR) and from the South African Weather Service.
One of the project participants actually wrote a PhD dissertation on wind resources in South Africa, however, it was too theoretical and not detailed enough, but it may serve as an excellent starting point when combined with our knowledge and technique."
For the next step, it was decided where to locate ten measuring masts along the coast to show the wind conditions at these sites. The 60-metre high masts are to transmit data on wind and temperature during 36 months on locations where you would expect a high yield and where the measurements can be compared with the models. Both are necessary input for the verification of models.
"The masts provide us with information about the wind; we will compare this knowledge with our modeled predictions, also taking into account our knowledge of the terrain and its obstacles, natural as well as man-made. The result is a map showing some red areas for the best suitable wind turbine locations, "says Andrea Hahmann.

A requirement from the banks


"It is more expensive to establish a wind farm than to build a coal-fired power plant, and the banks will not finance a wind farm if you cannot tell how much energy you expect it to get out of it.  That’s the way it is, even if you do not have to estimate fuel costs once the wind turbines are there," Andrea continues.
So, VEA's programme to map wind resources is actually a powerful tool for developing sustainable wind energy. In November and January Risø researchers are visiting South Africa again to organise courses and seminars for the public on their technique and their project.
Their results are to form part of development plans for wind energy in South Africa. And hopefully it will be possible to establish wind farms here in 2012. 

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