The major instrument for promoting cogeneration is the Energy Efficiency Directive ( 2012/27/EC, and its predecessor, 2004/8/EC), and which requires that Member States implement its provisions by 6 August 2007. The replacement of this is currently under discussion, but seems likely to take an approach which will more closely align it with the RES Directive.

The Cogeneration Directive includes harmonised definitions, Guarantees of Origin, access to electricity grids, identification and elimination of administrative barriers, the possibility of support systems for high-efficiency CHP, and the analysis of the national potential in Member States and statistical requirements.

Preamble (39), Article 14 and annexes 2 and 10 of the Cogeneration Directive contains the major provisions relating to GOs. These require Member States to put in place a system of GOs for highly-efficient cogeneration electricity. Member States must administer the system either themselves, or by appointing bodies independent of generation and distribution.

Similar to GOs for renewables, GOs must be reliable, accurate, transparent, fraud-resistant and recognised by all Member States. In addition to the general requirements of GOs (which are slightly less detailed than for renewables), cogeneration GOs must also declare the lower caloric value of the fuel source for the electricity, specify the use of combined heat production, quantify the electricity and specify primary energy savings.

The Commission helped AIB to develop the provisions of EECS that support cogeneration GOs in return for being permitted to approve the text; because AIB is controlled by competent bodies for GOs, and half of EU Member States are represented in AIB and have substantial experience in certificates; EECS is used and appreciated by the major commercial players and is robust and cost-effective, and because it can be implemented quickly.

To resolve some of the less-clear provisions of the Cogeneration Directive, the AIB has worked with stakeholders to reach an agreed interpretation of the Cogeneration Directive and developed a calculation model for its members.