Power Doppler creates a color image of the AMPLITUDE of the Doppler- shifted echoes.
Power Doppler is typically used to assess slower-moving flow or flow within small vessels.
Compared to color Doppler, power Doppler is more sensitive to flow, and much less angle-dependent. It also does not alias.
Standard power Doppler is unable to provide directional information. However directional power Doppler can provide directional information.
The adjacent video should give you a good understanding of power Doppler.