KVTs Wind Index

KVTs wind index tells how the mean wind speed during a specific period has been relatively to what is considered to be normal. A wind index larger/smaller than 100 % means that the wind speed in the analyzed period has been in average higher/lower than normal. Normal is defined as the mean wind speed during a long period.

The standard deviation of the annual mean wind speed is typically 3 to 7 % depending on the site in consideration. This inter-annual variability of the wind speed is associated with the intrinsic variability of the atmospheric conditions. It is therefore normal that the production of a wind farm also varies from year to year. A typical variation of the annual energy production of about 15 % may be expected in regions of high wind speed variability.

Kjeller Vindteknikk publishes each month the wind index for the preceding month (see our frontpage), and for the preceding last twelve months (see below). The published wind index maps cover the Norwegian and the Swedish territories, and tell us how the last month (e.g. September) has been compared to the average of all the September months of the chosen reference period. KVTs wind index is produced based on the KVT Meso long-term dataset produced by Kjeller Vindteknikk. More information on this dataset may be found here. The 16-years period 2000 to 2015 is used as the reference period.


KVTs wind index for the last twelve months (LTM).

Note that KVTs wind index may be used to give a rough feeling of how much your wind farm should have produced as compared to its expected normal production. However, Kjeller Vindteknikk recommends the use of a site specific production index calculated based on a wind index with higher spatial resolution, and based on the wind farm’s power curve, in order to more precisely analyze the performance of your wind farm. We offer this possibility through our products ProdOptimize and Production analysis.

For more information on KVTs wind index or on our services related to production follow-up and analysis please contact :

Lars Tallhaug    lars.tallhaug@vindteknikk.no   +47 95134839