This is one of the reasons that Apple switched from the PowerPC to Intel.
After a bit of browsing on Wikipedia and Freescale product pages, it appears to me that the mobile G4 chips typically used under 20 watts and had TDPs around 30. That's in line with (or below) the standard-power Intel chips found in the Macbook Pro from its introduction to current Ivy Bridge models.
There was also a low-power G5 processor that could, in theory have powered a laptop. Apple didn't go that route because it wasn't substantially (if any) faster than the G4, there wasn't a suitable northbridge, and the G5's idle power consumption was too high.
It appears Apple switched to Intel because there wasn't a suitable upgrade path for its laptops, not because then-current models consumed too much power or generated too much heat.
After a bit of browsing on Wikipedia and Freescale product pages, it appears to me that the mobile G4 chips typically used under 20 watts and had TDPs around 30. That's in line with (or below) the standard-power Intel chips found in the Macbook Pro from its introduction to current Ivy Bridge models.
There was also a low-power G5 processor that could, in theory have powered a laptop. Apple didn't go that route because it wasn't substantially (if any) faster than the G4, there wasn't a suitable northbridge, and the G5's idle power consumption was too high.
It appears Apple switched to Intel because there wasn't a suitable upgrade path for its laptops, not because then-current models consumed too much power or generated too much heat.