TomCon.Net was built with several recycled computers working on a local network. One recycled thinkpad t440s running the web server, gemini server, and encrpytion handling. One recycled Desktop PC running Kobold.
Theres a few ways to measure power. Either directly with a wattage metering device (sold between 10-30$USD) which plugs directly into your homes ac outlet as a middle man metering power draw. This is what I did for the following calculations. Another option would be to directly measure voltage and current then do some calculations to find out the precise wattage. I may consider doing this later.
Theres several ways to define power. Joules and Horsepower are common units, but typically when it comes to electrical power its easiest to think of by our system usage in watts used per hour. Also known as watt-hours or `Wh`. The simplest definition of power requires both an energy component and a usage-over-time component to be complete. For example, imagine a LED lightbulb rated to consume 10 watts turned on for an hour. The amount of power it consumed over that time is 10 watt-hours. A battery supply that stores 256Wh worth of power total can supply a lightbulb consuming 10wh for about 25 hours (256/10=25.6). Its an easy, practical, and complete unit of measuring power that your electric bill probably uses.
The thinkpad hosting the web site, gemini site, and caddy, consumes approximately 10 watts at idle. Under a light load it goes up to 25 watts. It doesn't do enough computational work to use the full power rating for maximum compute which would max out wattage to around 50-75. Ill have to do stress testing but upper wattage usage isn't a factor for our setup. It is idle almost all of the time.
The thinkpad while idle/serving pages and on 24/7 uses 10 watt-hours which is 240wh used per day.
kobold desktop does the majority of the heavy compute at tomcon.net. this desktop consumes 30 watts at idle. During light task like loading the model into GPU it consumes around 60-70 watts. When doing LLM inferencing under load the wattage usage spikes up to 200 watts.
The desktop sits idle most of the day currently, on average it does no more than one hour of heavy compute work per day. So 30wh*23hours+200wh*1hours > 690+200 > 890 or ~900Wh used per day.
Combining the laptop and the desktop total power usage, combined they use 47.5wh per hour or 1140wh per day. For perspective, a plug-in fan uses 80-100 Wh. A electric space heater that plugs into an outlet in north america is rated at 1500Wh. Tomcon.net uses less power than fan turned on low. In a whole day, tomcon.net consumes less power than a space heater turned on for an hour.
Theres room for efficency improvements.
Once the laptop is powered by solar energy its cost of energy operation essentially free so theres no billed cost to running it besides initial buying of parts. My current solar power system isn't enough to handle the desktop so that remains on grid power and cost a few dollars to keep on every month.
I paid 100$USD for the laptop second hand ~5 years ago. I paid 1000$ for the pre-built desktop new ~8 years ago. I paid 200$ for 200 watt solar panels new 2 years ago. I paid 100$ total for the batteries two years ago. I paid 20$ for the battery charge controller two years ago.
Some CO2 was released and non-renewable resources used up during the industrial processes to manufacture materials for these computer parts. Precious metals such as gold and lithium had to be mined out of the ground through intense human labor to assemble parts like circuit boards and batteries. High grade silica had to be manufactured for transistors and accelorator cards. non-renewable oil had to be frac'd, refined, and synthesized into non-degradable types of plastic for many parts.