I had a Proven 6kw turbine on a 15m mast installed last December after indications that it would generate around 8,000 kwhs pa. In fact its output to date is only 885 kwhs. The site is about 140m above sea level and open to the SW which is the prevailing wind direction. There are trees in other directions but some as much as 250m away. The Proven power curves sent to me by the installer showed 1kwh @ 5m/s, 2.6 @ 7 and 5.3 @ 10 ( I gather these have now been withdrawn). The turbine has never come near these figures and in strong, steady SW winds has only produced about 25% of what the power curves indicated - eg 12hrs @ >10m/s produced only 17.5kwhs against a power curve based expectation of 63! I have a Davis weather station sited near the turbine mast on its own mast of about 7m. Its data is fed straight into my computer at 10 minute intervals. Because the installer has not yet commisioned the turbine or issued a MCS certificate I cannot even claim FIT payments for the small amount so far produced.
Has anyone had similar experience or got any helpful, practical suggestions?