The practicalities of the test can be quite onerous, however, and depending on the wind regime at the site it can take months. The associated costs typically put performance testing beyond the reach of single turbine developments.
While certification schemes might provide sufficient confidence for installations up to 50 kW, the financial incentives are very attractive for midrange developments up to 500 kW – and it is precisely these developments that struggle to afford performance tests.
Fortunately a new edition of IEC61400-12-1 currently in preparation will include several measures to reduce the time needed to collect the required amount of data, thus lowering the costs. One of the changes allows for the use of remote sensing devices such as LiDAR as a partial replacement for tall masts. Once they are in common use, the way could be open for even more lightweight testing procedures in the future and with them further service opportunities for appropriately qualified companies.