Day vs Night Wind Speed Profiles

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Night Pbl Wind Profile

Figure 12. Comparison of the diurnal (diamonds) and nocturnal (squares) global average profiles of wind speed in 2000 obtained at the sounding stations (with at least 20 valid profiles) with the LS methodology for hub heights in 50-200 m.

Figure 12. Comparison of the diurnal (diamonds) and nocturnal (squares) global average profiles of wind speed in 2000 obtained at the sounding stations (with at least 20 valid profiles) with the LS methodology for hub heights in 50-200 m.

potential but are not represented here, further suggests that the values in this study (Table 1) are conservative. Examples are: (1) the Philippines archipelago was classified as class 1 in this study (Figure 8), but it was shown to have an excellent wind resource for utility-scale applications (at 30 meters) at mountainous and east-facing locations [Elliott et al., 2001c]; (2) Armenia, represented by only one class-1 station in this study, has excellent wind power potential on top of ridges and in mountain passes [Elliott et al., 2003]. Note, however, that all wind atlases cited in this study were obtained for a constant surface roughness of 0.10 m, considerable lower than the values found in the previous section (0.63-0.81 m). Also, they were valid at 30 to 50 m above ground, whereas this study focused on the 80-m hub height.

3.3. Global Wind Power

[51] In this section, the total wind power available globally for electric power generation at a direct cost of 3 -4 c/kWh is estimated. The following assumptions were made for this calculation:

[52] 1. Winds are Rayleigh in nature [e.g., Archer and Jacobson, 2003] (Figures 10 and 11).

[53] 2. The fraction of the Earth surface covered by land (without snow) Aland is 25.4% [Jacobson, 2001], corresponding to 1.3 x 108 km2. The fraction covered by water is 71.3%, or 3.64 x 108 km2, and that covered by snow/ice is 3.3%, or 0.16 x 108 km2.

[54] 3. The wind speed distribution over the globe is well represented by the wind speed distribution obtained from the 8199 stations used in this study. This is a conservative approach, as discussed in the previous sections.

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Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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