Class II Item no. 957688.R2

2006-09-13

Own Consumption Vestas V90-3.0 MW

Item no.: 957688.R2 Date: 2006-09-13 Class: II

Issued by: Technology Own Consumption

Vestas V90-3.0 MW Type: MAN

Page: 2 of 2

Normally, when the wind turbine is connected to the grid, the turbine’s own consumption does not influence the WTG power curve. This means that the first kW produced by the wind turbine is used for the turbine’s own consumption. I.e. if the nominal power of the wind tur-bine is 3000 kW, the turbine will supply a capacity of 3000 kW to the grid. The own consumption of the wind turbine is therefore defined as consumption when the wind turbine is not producing energy (generator is not connected to the grid). This is defined in the control system as Production Generator 0 (zero). The following components have the largest influence on the own consumption of the wind turbine:

• Hydraulic motor 22.0 kW • Yaw motors 6 x 2.2 kW 13.2 kW • Oil heating 3 x 1.0 kW 3.0 kW • Air heaters 2 x 6.0 kW 12.0 kW • Oil pump for main bearing / gearbox lubrication 7.5 kW • Controller including heating elements for

the hydraulics and all controllers max. app. 3.5 kW • HV transformer located in the nacelle has a no-load loss of max. 5.3 kW

This results in a total installed load of approximately 65.6 kW, and typically approximately 22 kW when the generator is not connected (including the HV transformer). The typical load is a result of the above mentioned consumers normally only being connected for a short time. E.g. the speed of the yaw motors is approximately 0.5 degrees per second, and the typical cut-in time for the yaw system is 2 to 5 seconds due to the usually short yawing length. The hydraulic motor is also only running at full load at intervals of a few seconds. The heaters are only active when the temperature is below the limits allowed, and typically only in the beginning of a production period due to the heating gained from power loss in ac-tive components. According to the above, the average own consumption depends on the actual conditions, the climate, the wind turbine output, the cut-off hours etc.