It’s the other way around. 0.1 kWh means 0.1 kW times 1 h. So if your device draws 0.1 kW (100 W) of power for an hour, it consumes 0.1 kWh of energy. If your device factory draws 360 000 W for a second, it consumes the same amount of 0.1 kWh of energy.

I’m likely to rebuild the backend in Go

Why bother with another language? Rust offers multiple great backend options. Using the same language for both ends might allow reusing some parts.