The principle of piezo technology cannot be compared with a solenoid valve. The core element is the piezo ceramics. When this is electrically charged, it creates a polarisation that causes the ceramic material to bend. The bending is proportional to the applied voltage and enables the flow rate or pressure to be regulated proportionally. The higher the voltage, the greater the flow rate. The current consumption curve is completely different than for a proportional solenoid valve, whose coil is permanently energised. This is the only way to generate the magnetic field that lifts the armature away from the valve seat. A piezo valve, on the other hand, does not need to be constantly energised, since it behaves like a capacitor. To charge the ceramic material once, all you need is an initial current and then the current consumption practically drops to zero.