Wind resources at Horns Rev

energy. environment. knowledge. Page 7 of 69
To keep the power consumption at an absolute minimum, two standard data loggers
were selected to scan the sensors. The sampling rate is 1Hz, and before being stored in a
flash RAM unit the data are condensed to 10-min mean values together with maximum,
minimum, and standard deviations for the averaging period. For the wind speed sensors
a 5-s gust is calculated as a mean of five consecutive 1 Hz values. The storage capacity
of the flash RAM unit is equivalent to 9 months of data.
The main components of the power supply were designed as simply as possible,
comprising a matrix of 2 x 5 x 50 W photovoltaic cells charging 25 NI-Cd batteries with
a capacity of 1070 Ah. The power system is capable of delivering 16 W continuously.
However, due to a miscalculation on the part of the erection contractor, the mast is
oriented + 33.1 ° wrong. Because of this mistake the photovoltaic cells deviate 33.1 °
from facing directly south, and are therefore unable to achieve the envisaged power
production. To compensate for that another 4 x 50 W photovoltaic cells were put up to
deliver the needed power capacity.
Figure 1.3 Fetch distances at Horns Rev
Direction Fetch (km)
N 280
NNE 62
NE 36
ENE 21
E 25
ESE 44
SE 62
SSE 80
S 190
SSW 240
SW 700
WSW 500
W 600
WNW 600
NW 700
NNW 700
Every spring and autumn the primary met system is subjected to regular maintenance,
and all sensors are replaced with newly calibrated sensors. Because the project has an
extra set of sensors to replace the existing ones, the system is up and running again in
only a few hours, and only one trip to the offshore mast is needed.
Report no.: D-160949
Tech-wise A/S is an international consulting Tech-wise A/S
engineering company specialised Kraftværksvej 53
in energy and environment DK-7000 Fredericia