Offshore installations are much more expensive, but Tobias Klaas, scientist at the Fraunhofer Institute for Wind Energy and Energy System Technology [IWES] in Kassel, says there “is still immense potential inland that remains to be tapped, such as in the low mountain ranges.” There are some facets of an inland wind project that still need to be investigated.
Planting a wind farm is no simple matter, especially in complex landscapes, like tree-covered passes and rocky valleys. Planners need very specific information to build a wind farm that is the most efficient possible, but measuring wind speed and direction on complex landscapes has, until now, been difficult or nearly impossible.
The problem comes in when trying to measure wind speed near the ground. Ground features, such as trees, rocks, ravines, among others, create drag and turbulence, which mean that detection equipment located anywhere up to 50 meters tells almost nothing of wind speed and direction higher up, where the turbine would be located.
Previous detection towers were only as high as 100 meters, but the blades of modern turbines easily reach double that height, so the data collected by these towers aren’t be very useful for planning a large-scale wind-energy project in the mountains of Germany. To give wind-farm planners better data to work with, Klaas and his colleagues at IWES, in January 2012, erected a 200 meter wind-detection mast, the tallest in Europe. Higher altitude wind pattern theories have been around for a while, but until now, no actual data could be collected.
To get more complete data, IWES’ tower is packed with instruments that detect wind speed, direction, and turbulence at various heights. Other measurements include barometric pressure, humidity, temperature, precipitation, and sunshine. “We have achieved a unique sensory device that allows us to determine the impact of these parameters on wind conditions,” says Klaas.
LIDAR, light detection and ranging, is a ground-based wind-detection unit that has a range of several hundred vertical meters, but wind experts don’t approve the unproven technology. IWES is hoping that they can use the tower to perfect the standards for LIDAR measurements of wind, and possibly make the detection towers obsolete.
The detailed measurements being logged by IWES’ tower will help planners of large-scale wind power facilities determine the proper orientation, height, and size of the wind turbines, to maximize efficiency and reduce expenses by not putting turbines where they’ll be of little use.