Turbines an ill wind for Cape traffic

02 Oct

Western Cape motorists should prepare themselves for major disruptions during the next few years, as massive wind turbine components are transported by road from harbours to wind-generating sites, many of them along the West Coast.

Preparation work on the roads will include the “significant” restructuring of some intersections, along with the temporary removal of signage and fencing to accommodate the extremely long and heavy loads, the Windaba 2011 wind energy conference at the Cape Town International Convention Centre heard on Thursday.

Engineer Sisa James of the GreenCape Initiative, a non-profit, co-operative venture to promote sustainable development in the province, said that about 1850 megawatts of wind energy were expected to be procured by 2015, during the first round of the government’s programme to buy renewable energy from independent power producers. Bids from these producers must be submitted by November 4, with the preferred bidders scheduled to be announced three weeks later. The first turbines are expected to be operational by June 2014.

James said they had estimated that generating this amount of power would require about 925 wind turbines, which translated logistically into 6 475 “abnormal loads” over a two-year period, or about 13 abnormal loads every day.

“They will be constantly on our roads for the next two years,” he predicted.

Although some wind energy projects would be built in the Eastern and Northern Cape, most would be in the Western Cape, along the West Coast.

Many people asked why the giant wind turbine components could not be transported by rail, but James said that would require “significant” investment in new equipment and infrastructure.

“The honest answer is that we’ve spoken quite a lot to Transnet and they still don’t have the picture.”

He explained that the abnormal loads would include the three 45m blades per turbine, which would create a significant length problem for hauliers.

The 3.5m x 28m towers would create a height problem for passing under bridges, as would the 3.5m hubs which would be a “very bulky” load.

The 80-tonne nacelles – the aerodynamic structures on top of the towers that contain the gearbox, low- and high-speed shafts, generator, controller and brake – would create both weight and length problems.

“They have to distribute that weight over many axles, and that can cause a vehicle to be quite long,” James said.

Primary issues for the transport of the wind turbines were route clearances, including intersections where turns were required; the shortage of cranes, both to offload vessels bringing the components from overseas manufacturers and to erect the turbines at the site; the maintenance of and possible damage to gravel roads; and moving components between individual turbine plots on site.

GreenCape had managed to convince the Saldanha Bay port authority to make cranes available and had offered to lease an overall staging area in which hauliers could in turn lease smaller areas as required, James said.

They had calculated that about 112 dedicated traffic escorts would be required to accompany the abnormal loads and the Western Cape transport department was considering appointing private escorts.

“There is a very significant safety factor that they emphasise very strongly.”

The province had set up a wind turbine transport co-ordinating committee to deal with issues such as shipment scheduling, a joint staging area and route and road clearances, otherwise there could be “very, very big problems”, James warned.

“Communication is key, and it will be especially important after the preferred bidders are announced.” –

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Posted by on October 2, 2011 in Have your Say


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