The first offshore wind farm in Sweden; Bockstigen, consists of five 500 kW stall controlled wind turbines. This report deals with power performance, offshore power production versus onshore ditto and park effects. The power output from individual passive stall controlled wind turbines were shown to vary significantly. The annual energy production at a mean wind speed of 8 m/s varies between turbines from 1420 MWh to 1539 MWh. The magnitude of the actual increase in energy production is severely affected by the availability of the offshore wind turbines. A 20% gain in energy production offshore over onshore ditto is noted as the availability increased in 2005. The reference onshore location is a premium wind site rarely available elsewhere. Hence, the 20% increase in annual energy production by moving offshore can be expected to be even higher if compared to other on-land sites. The park efficiency is shown to be 98% for the actual wind direction distribution. A worst-case shift in wind direction only decreases the annual energy production by 0.5%. The reason for this minor influence due to wind direction is the large average distance, x/D!10, between neighbouring turbines in the Bockstigen wind farm. An increase in air turbulence causes an increase in power performance. The load measurements in the lattice tower can be used to asses an estimate of wind speed and wind direction.