During startup (when the hot rod igniter is running) this is when a pellet grill will be pulling the most amount of power/electricity. During startup to get the hot rod igniter glowing, it will be pulling several hundred watts of power up to maybe 500 watts. 

However, this will only last for very short amount of time (typically less than 10 minutes) to get the pellet fire established. Once the controller can see the internal temperature of the cooking chamber rising it will cut power to the hot rod igniter.

During operation (once the pellet fire is established) electrical consumption will be well under 100 Watts to run the control panel and induction fan. When the pellet feed auger turns on, the power consumption will typically jump over 100 Watts, but again the auger doesn't run constantly.