Canon Powershot Sx20 Is
Can the Canon PowerShot SX20 IS to shoot in RAW format?

so are the advantages of shooting in RAW?

No, no SX20is Canon takes pictures in RAW, the raw image can have a wider dynamic range color spectrum or the eventual final image format, which retains most of the information captured image. RAW image formats' purpose is to save with a minimum loss of information data obtained from the sensor, and the conditions surrounding image capture