How Horizon 7 applies the configured power policy to automated pools depends on whether a machine is available.
A machine in an automated pool is considered available when it meets the following criteria:
Does not contain a user session
Is not assigned to a user
The Horizon Agent service running on the machine confirms the availability of the machine to Connection Server.
When you configure an automated pool, you can specify the minimum and maximum number of virtual machines that must be provisioned and the number of spare machines that must be kept powered on and available at any given time.