This Technical Report, analyses and describes the concept of energy efficiency obligation schemes and white certificate schemes for energy efficiency improvement, based on the experiences in Europe. It is mainly focussed on the current systems in use in Italy, France, Denmark and Great Britain. These national systems have been in operation long enough to gain some valuable experiences about the systems. Information about these experiences is easily accessible. Some additional information about the regional system in Flanders, Belgium, Poland, Ireland, Spain and Portugal have been included in this Technical Report when considered relevant. This Technical Report also analyses the need and/or possibility to harmonise a system in Europe (i.e. to write a standard). It also includes an analysis of some countries' hesitation to introduce white certificate systems.