powercfg /availablesleepstates

The following sleep states are not available on this system:
    Standby (S1)
        The system firmware does not support this standby state.
        An internal system component has disabled this standby state.
                Graphics

    Standby (S2)
        The system firmware does not support this standby state.
        An internal system component has disabled this standby state.
                Graphics

    Standby (S3)
        The system firmware does not support this standby state.
        An internal system component has disabled this standby state.
                Graphics

    Hibernate
        Hibernation has not been enabled.
.../...

powercfg