I found a cool clamp that allow to remotely measure the energy. The Aeotec Home Energy Meter (ZW095) is finaly a clamp with the abilitie to measure voltage.
That should allow to measure precisely energy (kWh), unlike other clamps which only have the intensity measurement.
There is many ZWave controllers and application for communication. If anyone can give it a try, i'd be happy to show it supported by mN
