My Raspberry Pi cluster consists of 4 mini computers that are always on. They all have fans running to keep them cool. So how much does this cost to run? And how much does it cost to analyze a game?
Data Gathering
All of my Raspberry Pis are connected to a USB charger. Check out the parts list here. I just plugged that charger into a Kill-a-watt energy usage monitor. This measures how much power is being consumed by whatever is plugged into it.
My local energy company charges about $0.11 per killowatt hour (kWh). This varies depending on the time of the year, but I’ll just use this number for simplicity.
Finally, I used this online calculator to add up the numbers.
Results
When the cluster is idle and not processing, it consumes about 10 watts of energy. When it is actively running stockfish and analyzing, it consumes about 30 watts of energy. This is for all 4 computers together.
Just for the sake of simplicity, I’ll say it sits idle 23 hours a day and is active for 1 hour a day while I’m analyzing a game.
| Idle | Active | Total | |
|---|---|---|---|
| Power Consumption | 10 W | 30 W | - |
| Time Per Day | 23 Hours | 1 Hour | - |
| Price Per Day | $0.03 | $0.003 | $0.033 |
| kWh per year | 84 kWh | 11 kWh | 95 kWh |
| Price per year | $9.24 | $1.21 | $10.50 |
So this cluster will cost me about $10.50 per year in energy costs.
For one game, it is less than a penny to analyze.
Final Thoughts
I was a little disappointed that this Raspberry Pi cluster was not very powerful. However, the thing that is hard to beat is that it is fairly energy efficient.