Short assessments

At a very early stage of the planning process, a very reasonable step may be to pre-evaluate the site or the region with respect to the wind resource and further relevant aspects. Through this, the first strategic decisions can be made very easily and at a very cost-efficient level before the costly processes like wind measurements, contracts or further approvals need to be scheduled.

With respect to the current tenders, these short estimates on the basis of a short term wind measurement can provide an immense strategic benefit. Already after a measuring period of approx. 3 months, a sufficient reliable evaluation with regard to the energy production is possible. Particularly, the frequency distributions of both the wind speed and the wind direction as well as the turbulence intensity can be determined very precisely via these short term measurements so that further decisions about the planned turbine type, the layout of the wind farm or the load on the turbines can be concluded from that.

Whilst the wind energy production of a wind farm can only be predicted reliably on the basis of at least one year of on-site or near-site data (i.e. measured wind data or production of nearby wind turbines), it is often strategically beneficial to decide upon the turbine type and wind farm layout at a relatively early stage of development, i.e. before the wind resource is well known. For this purpose, aj offers early stage site condition assessments and wind farm lay-out studies. If a wind measurement has been lasting for a few months, the relevant parameters can often already be determined with the accuracy necessary for this purpose. Of course, seasonal effects must be taken into account in these cases. If a wind resource study is based on production data of nearby turbines, aj determines the most uncertain parameters on the safe side specifically for this purpose, which will allow for acquiring a building permission on safe grounds.

At aj, the short estimates are based on production data of existing wind turbines in the surroundings of the planned site. Thus, the same procedure is used as in full wind resource and energy production assessment reports which is much more reliable as carrying out short estimates on the basis of model calculations only. Through this, potential risks can be identified much easier and additional steps, such as wind measurements or the need for production data of further turbines, can be planned, if necessary, much earlier.