High Intensity Dischage(HID) Lamps Ballast Loss?

How much is the standard ballast loss for High Intensity Discharge(HID) Lamps?

G'day Text. I think the wattage rating of ballasts include the power loss.

If you want to know the actual power loss of a ballast then the manufacturer should be able to provide that.

I would assume that:

Power loss = ballast wattage - lamp wattage.

Text,
It really depends upon which type of HID lighting system you are talking about.
As you go up through the HID Index as in:
Sodium> Mercury Vapour>Metal Halide.
The losses get reduced, but it is at the cost of higher strike voltages.
Personally, if you were going for lowest loss as far as ballasts were concerned, look at the new T5 Fluorescent tubes, they use High Frequency Ballasts and they also are taking on High Bay Metal-Halide and Mercury Vapour in terms of Light Quality and Energy Efficiency. [Linked Image]

is there already available dimmer for HID?

I can't say I've ever heard of someone actually dimming an HID lamp, I'm not even sure if it would be possible.