How to get Intel iMac (or Mini) to remain in "deep" sleep (hibernatemode 25)?

The lost post is redundant; uninterupted sleep has worked; here is the guide:

iMac & Mac Mini Deep Sleep Setup Guide

(Explanatory notes for each numbered step are located at the bottom of this guide. Code blocks for steps 4 and 6 are located in the Additional Text box.)

Quick Setup Steps

1. Download and install Hammerspoon from hammerspoon.org, then enable permissions under System Settings > General > Login Items (Open at Login) and Privacy & Security (Accessibility and Input Monitoring).
2. Open the Calendar app, go to Settings > Alerts, uncheck "Time to Leave", and set "Events" and "All Day Events" to None.
3. Open Terminal and run:

sudo pmset -a tcpkeepalive 0 powernap 0 womp 0
sudo launchctl bootout system/com.apple.osanalyticsdIn Terminal, run sudo nano /Library/Preferences/FeatureFlags/Domain/powerd.plist, paste Script 1 (from the Additional Text box), press Ctrl + O (then Enter) to save, and Ctrl + X to exit.

1. In Terminal, run sudo nano /etc/sudoers.d/btt_bluetooth, paste z ALL=(ALL) NOPASSWD: /usr/bin/pmset, /bin/launchctl, press Ctrl + O (then Enter) to save, and Ctrl + X to exit.
2. Click the Hammerspoon menu bar icon and select Open Config. Delete any existing text in the document, paste Script 2 (from the Additional Text box), save the file (Cmd + S), and click Reload Config in the Hammerspoon menu bar.
3. To put your Mac to sleep, press Option + /.
4. To wake your Mac, press the physical Power Button, then wait 15 seconds before interacting.

Explanatory Notes

• 1: Hammerspoon requires accessibility and input permissions to detect global keyboard shortcuts and trigger actions without security prompts.
• 2: Calendar "Time to Leave" and event alerts schedule hardware real-time clock (RTC) alarms that bypass system sleep settings.
• 3: Stops background network polling and unloads the telemetry engine (osanalyticsd) to prevent automated background wake events.
• 1 : The powerd.plist file overrides system feature flags to permanently stop hardcoded 2-hour maintenance evaluation dark wakes (CSPNEvaluation).
• 2: Grants Hammerspoon passwordless execution rights for system power and launch control commands.
• 3a: Clearing default text in Hammerspoon prevents Lua syntax errors.
• 3b: The script unloads Bluetooth before sleeping to prevent peripheral wake-loops in deep hibernation (hibernatemode 25). Upon power-button wake, it restores Bluetooth and resets the system to light RAM sleep (hibernatemode 0) so short daytime idle breaks do not cause excessive write wear on your SSD.
• 3c: A 2-second buffer prevents physical key-up actions from canceling the sleep command.
• 4: Gives macOS 15 seconds to re-establish Bluetooth, Wi-Fi, and background services, preventing UI lockups when clicking complex elements.

Verification

To check that deep sleep has fully worked, run this command in Terminal:

Bash

pmset -g log | grep -E "Sleep|Wake|DarkWake" | tail -n 250 > ~/Desktop/pmset_sleep_log.txt

This will generate a text file named pmset_sleep_log.txt on your Desktop. Inspecting the log should show no entries between the moment sleep was initiated and the moment the machine was woken by the power button.

The numbering system went awry when pasting so the revised (2nd step 1.) explanatory note for the second "1."should have "global" replaced with "relevant" and any content in the Nano file replaced with the following BUT with your username at the commencement of each line (type: "whoami" in Terminal, if unsure of name) or use %admin as below:

%admin ALL=(ALL) NOPASSWD: /usr/bin/pmset -a hibernatemode 25

%admin ALL=(ALL) NOPASSWD: /usr/bin/pmset -a hibernatemode 0

%admin ALL=(ALL) NOPASSWD: /usr/bin/pmset schedule cancelall

%admin =(ALL) NOPASSWD: /usr/bin/pmset sleepnow

%admin ALL=(ALL) NOPASSWD: /bin/launchctl bootout gui/* /System/Library/LaunchAgents/com.apple.bluetoothuseragent.plist

%admin ALL=(ALL) NOPASSWD: /bin/launchctl bootstrap gui/* /System/Library/LaunchAgents/com.apple.bluetoothuseragent.plist

According to the numbers I've seen; with just the Display off an Intel iMac will be using about 47 times more power than if in deep (hibernatemode 25) sleep - so for those who leave the device on most of the time, that is the equivalent of leaving a couple of LED lights on all day and night to save having to flick the switch (and wait a few seconds). Have you advised/explained to Apple Inc. that for general users "do not use sleep (which can cause other issues)"; they would have to be considerable to burn 70 or so kWh per annum?

What was in my lengthy response/answer that you didn't receive? It seems that I needed to hit the Post button and probably failed to do so as I was constantly going back and forth checking facts. I didn't ask for questions but for one answer and so far no meaningful response; it looks like there is nothing in this community on the topic; maybe owing to a lack of interest or to the complexity.

Subject to further testing over some time it looks like I've managed to get total uninterupted sleep working for 3 hours so it should be permanent. It can't be achieved via GUI or pmset so it looks like it's up to me to write the guidance; I had thought/suspected that this must have been done and published and that I was just "reinventing the wheel"; do you want a copy; there doesn't seem to be any suitable section here for tutorials etc. so it may need to go onto Github or similar.

It's a moot point now, but the suggestion to try: Prevent automatic sleeping....display is off - seems odd as that is the only setting I'm aware of which is intended to stop any sleep and override any settings other than so called "Display sleep."

I've generally understood that for any phone/computer that the consumer of the most energy is the screen; what was somewhat revelatory in this project was to discover that the main reason to use a Sleep setting rather than just "Display off" is that the "screen" remains using much of the power even with the display off. This is less so with a Mini but it will still be using about 1000% more compared to hibernatemode25 (deep) sleep; that's about 20 kg of CO2 annually; if 40 million users don't bother going beyond Display sleep.... I'll let you do the math.

I've just changed my settings on the iMac to set it for Display off only - for when I've gone on short breaks - often longer than planned, but that's owing to complexities in my setup such that it's that or manually forced Deep sleep; which has worked and with no instability issues, and is used daily.

The numbering system went awry when pasting so the revised (2nd step 1.) explanatory note for the second "1."should have "global" replaced with "relevant" and any content in the Nano file replaced with:

z ALL=(ALL) NOPASSWD: /usr/bin/pmset -a hibernatemode 25

z ALL=(ALL) NOPASSWD: /usr/bin/pmset -a hibernatemode 0

z ALL=(ALL) NOPASSWD: /usr/bin/pmset schedule cancelall

z ALL=(ALL) NOPASSWD: /usr/bin/pmset sleepnow

z ALL=(ALL) NOPASSWD: /bin/launchctl bootout gui/* /System/Library/LaunchAgents/com.apple.bluetoothuseragent.plist

z ALL=(ALL) NOPASSWD: /bin/launchctl bootstrap gui/* /System/Library/LaunchAgents/com.apple.bluetoothuseragent.plist

This started as a "5 minute project" to save that 1 watt of wasted power usage and a key element was to not have to use the power button (based on probably exaggerated fear based on experiences where buttons have been first source of degradaion for a number of devices). Since it can't come out of hibernatemode 25 with other than the power button that has fallen by the wayside (actually it may be possible via a Bluetooth signal).

It is normally turned off overnight - so this 30+ hour investment is only used for abscences of around > 40mins; the total sleep is req'd to stop the repeated writes of RAM to Disk to RAM which occur with any brief maintainence wakes. This device has a non -Apple SSD installed which does apparently add considerably to the start time. Thanks for the question it's led me to commence checking out the Bluetooth start and TRIM starting delay.

While the effort to outcome ratio has been dubious it has led to a lot of insights into numerous elements of the Sleep setup; script functions and syntax, GUI vs Terminal, and customer friction minimization outcomes. At some point I started to set this up on a MacBook (where it's more useful) and it took about 2 mins with no apps/scripts or Terminal commands that I can recall so that was unexpected and pleasing.

I wrote a lengthy reply and it seems to have vanished; will check later in case it's gone off into some moderation area ( I did mention "Hammerspoon").