European Residual Mix Calculation

Grexel is responsible for calculating the European Attribute Mix and Residual Mixes for Europe on behalf of the Association of Issuing Bodies (AIB). These mixes are used by Energy Authorities and Grid Operators of several countries to ensure reliable electricity disclosure.

AIB is the leading enabler of international energy certificate schemes throughout Europe and has taken on the responsibility for coordinating the calculations of the European Attribute Mix (EAM) and Residual Mixes (RM) for Europe, as a legacy of the RE-DISS (Reliable Disclosure Systems for Europe) project.

Having calculated the EAM and RMs for the past 5 years as part of the RE-DISS project, Grexel Systems is pleased to provide its expertise to AIB in this critical task.

Why is a reliable Residual Mix calculation so crucial?

Under EU’s Internal Energy Market Directive (2009/72/EC, Art. 3(9)), electricity suppliers must inform their customers of the origin and environmental attributes of sold electricity. This is called electricity disclosure. The aim is to enable informed consumer choice, and for that choice to be based on other matters than electricity prices alone, such as environmental values. In a liberalized market, electricity disclosure requires reliable tracking of the required attributes from generator to supplier.

For renewable energy, tracking is often done by associating electricity sales with cancelled Guarantees of Origin (GOs). However, without the residual mix calculation, renewable electricity sold with GOs could be double counted where disclosure information is presented to consumers buying “regular” electricity. The presence of a reliably calculated Residual Mix makes the entire disclosure system reliable, by determining and correctly disclosing to consumers that are purchasing a non-specific type of electricity, what is left in the power system after explicit tracking by means of GOs.

European Attribute Mix (EAM) is needed to coordinate national residual mixes. Since the Guarantee of Origin system is Europe-wide, it is not sufficient for each country to determine its respective residual mix internally: a coordinated European Attribute Mix needs to be calculated by a Central Body (AIB with Grexel) and applied by national Energy Agencies and/or Grid Operators, to replace the deficit of energy origin caused by exported GOs. This is why taking the task of coordinating the EAM calculation complements the HUB service of AIB extremely well: it informs countries of the origin of the energy they receive in return, when GOs are exported via the AIB HUB. This is a prerequisite for a complete and reliable electricity disclosure scheme, and is the other end of the loop for AIB’s HUB service.