The wind climate displays large seasonal variations. The average wind speed is presented for
different averaging periods.
Averaging period: Year
Year
Spring
Summer
Autumn
Winter
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Large picture
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Large picture
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Fig. 1
Digital terrain model
Fig. 2
Wind speed at 50 meters height
Measurement station
Averaging period: Year
Interpolated or translated
measurement station
Wind turbine(s)
Area classification
The total model area is:
629 km2 while the area above land is:
418 km2. The land area is classified in four groups according to the average wind speed at
50 meters height. The first and largest group cover the land area where the average wind speeds is above 6 m/s.
The subsequent groups covers reduced areas as the average wind speed is increased to above 7 m/s, 8 m/s and 9 m/s.
The suitability of an area for wind energy purposes depends on the size of high wind speed areas.
Further it will be an advantage if the high wind speed areas are grouped or connected.
Table 1 classifies areas according to minimum wind speed and minimum size of connected sub-areas.
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>6 m/s
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>7 m/s
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>8 m/s
.
>9 m/s
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> 0.04 km2
344.2
(82)
238.8
(57)
120.8
(28)
46.8
(11)
> 0.10 km2
343.7
(82)
237.1
(56)
117.9
(28)
44.6
(10)
> 0.50 km2
339.6
(81)
229.6
(54)
106.0
(25)
33.2
(7)
> 1.00 km2
338.4
(80)
225.7
(54)
96.0
(22)
22.0
(5)
Table 1.
Areas in km2 classified in groups according to minimum average wind speed and minimum size
of connected sub-areas, number in brackets is the area in the group as a percentage of the total
land area
Energy production
The maximum theoretical energy production from the total land area with wind speed above 6 m/s is: 15513 GWh
/year
The energy production is based on an installed capacity of 15MW/km2.
The installed capacity will only be obtained when the wind speed typically exceeds 12-13 m/s.
For lower wind speeds a wind turbine produces its installed capacity only a fraction of the time, usually
expressed as full load hours. The right figure gives the relation between full load hours and average
wind speed used in the energy calculations in this study:
Energy calculations.
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>6 m/s
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>7 m/s
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>8 m/s
.
>9 m/s
.
> 0.04 km2
15513
(100)
12056
(77)
6906
(44)
2925
(18)
> 0.10 km2
15431
(99)
11937
(76)
6733
(43)
2792
(17)
> 0.50 km2
14993
(96)
11388
(73)
5990
(38)
2079
(13)
> 1.00 km2
14714
(94)
11019
(71)
5358
(34)
1378
(8)
Table 2.
Energy production in GWh/year for an installed capacity of 15MW/km2, the number in brackets
gives the produced energy as a percentage of the total possible energy production for the land area.
Climatology
The wind resources in the model is based on the following wind climatology(s):
Buholmsråsa, external: Sør-Trøndelag 7
Buholmsråsa and Rørvik interpolated (0.6 + 0.4)
Rørvik translated, external: Nord-Trøndelag 2
Particular comments: The wind speed may be slightly overestimated
at the areas longest inland from the average coastline.