Since RAM is a volatile memory and requires electrical power to hold data your system while in suspended state continues to use electrical power. To suspend/sleep your Redhat/Fedora system you can enter the following command:
rhel7~]$ systemctl suspend
Depending on the system settings you may be required to execute the above command as a root user. The system will not go into a suspended state while users are logged in. You can overwrite the suspend inhibitors with
rhel7~]$ systemctl suspend -iJust to be complete the suspend state is not to be mistaken with hibernate state. In hibernate state the system running state is save to hard drive thus not requiring electrical power to maintain hibernation.