ErP/EuP (Energy Using Product) is a function to save power when the computer is in standby mode. This is a regulation so the total power of the system won't exceed 1.0W
You need a ErP ready power supply and motherboard to have a ErP/EuP system.
Here's a little test: http://forums.vr-zone.com/hardware-depot/1295397-what-eup-erp.html