Looks to me like people are participating and theory crafting.
Several months ago I used a Sata 2 USB adapter with a SP 240GB SSD and I was amazed how little power it took. I was thinking I could make useful server running at 1 watt. Don't know if it's going to be possible. But will be fun trying.
The plan for my attempt: I have a collocated server in Cleveland. I plan to create a local backup mirror of the web/php/mysql/IRCD/FTPD services I can redirect DNS in an outage. I also plan to install Samba for networking. This will create a network share for home files, and a media share for smart TVs and phones to play stored video files.
I going to use a SP 512GB SSD (was going to be 240GB but 512GB was on sale). UGreen Sata2USB (hacked to power Pi0W), and the Pi0W which will connect wireless tot he network. Based on past tests I hope to get everything under 1W power if possible.
After getting in the hardware I had to do a tiny bit of hacking. The Ugreen uses a 12V adapter which I wanted to power the Pi. So I soldered some wires to the + - of the power port.
Next I drilled a hole for the wires to come through.
Next I soldered the wires to a 12V to 5V USB buck converter. I then hot glued the adapter to the top of the Ugreen.
Powered up the Pi0W boots off the fat partition on the SD card. However it loads it's file system off the SSD after initial boot.
Initial tests for this system with Pi0W HDMI and lights set to off lowest power is 100ma at 12V (1.2 watts). However when CPU load goes up so does amps drawn averaging around 150ma. I see a couple of problems. Even with all those servers CPU usage will be below 1-2%. But there will be spikes at times. My biggest draw the 512GB SSD is twice the weight of the 240GB (gave to a friend) and I suspect the extra chips are pulling extra power which has pushed me over. There is a light on the 12V2USB adapter and the Ugreen as well as 2 LEDs inside the SSD not visible unless you open it up. I could clip the LEDs on the adapters (not sure I trust doing that to the SSD). But that still won't be enough power saved. I could try underclocking the Pi0W (if even possible) to see what that gains me. The other "big" power draw is the SDcard reader. SDcard reader is used at boot but not after that. I wonder if there is a way to manually turn it off to save power like you can the HDMI?
I'm working on hitting 1 watt and keep my 512GB SSD. We'll see how it goes. If everything works according to plan, I will also put a little solar panel outside my window to feed a battery to run this server. Positive suggestions welcome.