First South African prototype 50 m wind turbine rotor blade.

Local wind turbine manufacturer Isivunguvungu Wind Energy Converter (I-WEC) has completed its first prototype 50 m wind turbine rotor blade.

The prototype was initially expected to take one month to manufacture but the process turned out to be more challenging than initially thought, ultimately taking approximately two months to complete.

Facilities and planning engineer Simon Graaff told Engineering News Online that the team rather wanted to produce “the perfect blade”, than rush the process. “It has taken longer but we are pretty confident this one is 100%,” he said.

The rotor blade has been manufactured using approximately 300 layers of four main materials, these being balsa wood, glass fibre, PVC and epoxy resin.

The I-WEC team manufactured the prototype under the supervision of advisers from Aerodyne, which is the German engineering company specialising in the design of large-scale wind turbines from whom I-WEC obtained the turbine design under licence.

The prototype blade would undergo static load testing, as well as a resin frequency test in April. Graaff explained that the static load testing would involve flexing the blade up to 8 m and would be carried out in the Cape Town harbour where there would be sufficient space.

As the prototype rotor blade had been completed, manufacture of components for the first production blade had already been started, said Graaff. He said that the next blade should take in the order of two weeks to manufacture, with the ultimate target being that a single rotor blade should take less than a week to manufacture under standard production conditions.

It was anticipated that the first 2.5 MW turbine, which required three 50 m rotor blades, would be completed by the end of May. Graaff said that the bulk of the parts required for the turbine generator had already been received and assembly on the generator would begin shortly and be completed in a time frame of approximately two months, testing included.

The first completed turbine would be erected at the ArcelorMittal South Africa’s (Mittal’s) Saldanha steel plant and would be fully financed by I-WEC, which would be selling the power generated from the turbine to the steel plant.

This turbine would also act as a demonstration model for the company, financial director Thomas Schaal, told Engineering News Online. “We are currently negotiating with them [Mittal] for the extension of the wind farm to an additional five turbines and to supply the energy most likely to them in the second and third quarter of 2013.”

He said the cost of the turbines being produced by I-WEC would be in the order of R12-million to R17-million per megawatt, which he believed was competitively priced against imported wind turbines.

Schaal added that increased interest was being shown in I-WEC especially as the third renewable energy independent power producer bid round approached, as the company would be able to assist in meeting the local content requirements. “That is one aspect, but we are also providing a state of the art product . . . we have acquired from Aerodyne the best technology you can get of world standard with world performance,” he stated.