On-shore wind turbines

Composite materials/fabrication techniques for on-shore and off-shore wind turbines... 

This section will describe one unique on-shore and one unique off-shore wind turbine. 

Figure 5.77 shows the wind potential for Denmark, on land and inland seas. The off-shore potential has been estimated for a number of reserved locations, shown in Fig. 5.78. These have been selected as suitable for wind turbine parks without disturbing fishery activities, boat routes for passengers and freight, military exercise areas, etc. The total exploitable wind power is given in Fig. 5.78 for each reserved area. It by far exceeds the envisaged 2050 electricity use. In several of the areas, wind power production has already been initiated, albeit at a total level substantially lower than that of the 2050 scenario. The year 2003 installed capacity is about 3.3 GW.

The wind turbine rotor blades, both for on-shore and off-shore wind farms, are exposed to various hostile conditions such as extreme temperatures, humidity, rain, hail impact, snow, ice, solar radiation, lightning and salinity. In order to withstand these external conditions without diminishing safety, a sound knowledge of the fatigue behaviour of the material and structural properties is needed. 

The global WT failure rate was assumed to be 3.8 failures/turbine/year, based on an initial onshore value of 1.5 and conversion coefficients K1 = 1.75 and K2 = 1.447 for environmental stress and near shore location respectively (Karyotakis 2011). The components contribution to total wind turbine failure rate was then obtained from (Rehawind 2010), where exponential distribution is assumed. 

Figure 5.78. Off-shore areas set aside for wind power production by Danish planning legislation. For each area, the legend gives an estimate of the total annual production possible from wind parks in that area. Considerations of minimum spacing between turbines and optimal configuration enter these estimates (based on Danish Power Utilities, 1997 Sorensen et al. 2001).

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