Finding Optimal Wind Turbine Positions in Complex Terrain

Even more so than for offshore wind turbines, placement of onshore wind energy converters (WEC) is critical to ensure performance, high life expectancy, low maintenance costs and safety. Especially in complex terrain (hills, mountains, built environment, tall trees, ...) and with many turbines - especially in re-powering situations with a mix of old and new turbines - it is a real challenge to find the ideal spot. Large Eddie Simulation (LES) is optimally suited to investigate such situations in detail and to have a sound base for making investment decisions. We are running massive simulations over areas of up to 25km², with atmospheric boundary layer (ABL), synthetic eddies (gusts) and optionally also radiation and humidity

Have a look the the animation below - as a demonstration we are showing more than 300 WEC in the area of the Tehachapi pass wind farm. The terrain is complex with flat stretches and hilly areas and there is a mix of smaller and larger turbines all of which have been simulated including their wake effect on the flow field (actuator disc model, see image below).


 

Download video: Full HD - 1080p | HD Ready - 720p

The simulation was done with ~40 Mio cells and a resolution of down to ~1.5 m (take a look at a similar mesh here). The total extent of the domain is 4km x 2km x 1km = 8 km³ (LxWxH), the simulated time span was 20 minutes which took us just 1 week wall clock time to simulate. Terrain and the placement of most of the WECs is accurate, but we took some liberties with the WEC type.

Simulations like this go above and beyond the pure suitability of a planned WEC in site assessments according to DIBt "Richtlinie für Windenergieanlagen" or IEC 61400. Influence of turbulence through interaction with terrain (we can even include tree influence, if necessary) or other WECs can be assessed in detail to get the best possible information as basis for decision-making. The increase in performance, safety and maintenance efficieny that can be expected is well worth the effort to have the best possible planning process and not just the bare minimum. Get in contact, if you want to know more!