Energy saving light bulbs are falsely marketed! Power = Volts * Current or volts x amps.
Nelson have a compact fluro light Australian approval CA V04116 ..Now taking the data from the light bulb DCELS15bccw6p - 15w 220 -240-50hz 87mA

Now if you take there figures that are written on the 15watt bulb, the true power used is 20.8 watts not 15watts as stated
therefore from ohms law Power drawn form supply = 240 x 87mA = 20.88watts. All this is controlled by the Fair Trading department and it shows that the department gets it wrong on many occasions.
You can see there is a problem as they state there bulb uses Watts 15 watts of power but if you work it out from the values printed on the bulb it works out to be 20.88watts, I guess it takes Watt or Eddison  to work this out cause the Fair Trading Department can't.