Implement power saving using manageIQ

Having 5 nodes with Ovirt and ManageIQ on top for managing the day to day VM/APP requisites. We want to implement power saving through ManageIQ automation.
Went through “Mastering CloudForms Automation”, by Peter McGowan but didn’t got any clue to how to archive power savings.
To start with wanted to schedule conditional shutdown and startup for few hosts and VMs to save power.
Please help or provide directions to archive

we use a tagging system, power_on, power_off and weekends then run a cron job to call an automate task that finds vms/instances with these tags and put them in the required state