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Calculating the residual mix

The Energy Authority annually calculates Finland's national residual mix and publishes it by 30 June. 

In the residual mix, sources of energy are divided into three groups: renewable, fossil and nuclear power. The residual mix includes information on each energy source's percentage and the average carbon dioxide emissions of electricity production according to the residual mix (g/kWh) and the average amount of nuclear fuel used for electricity production (mg/kWh).

In 2016, the residual mix of Finland included 9.13% of electricity produced from renewable sources, 43.51% of nuclear power-based electricity, and 47,36% of electricity from fossil sources. The average carbon dioxide emissions of electricity production according to the residual mix were 287,81 g/kWh and the amount of spent nuclear fuel was 1.23 mg/kWh. 

The calculation process of the residual mix commences by determining the volume of non-certified production on an energy source-specific basis. The determining of non-certified production accounts for electricity net production  in Finland and electricity net imports from Russia, as well as the imports, exports and cancellation of guarantees of origin. A guarantee of origin shall be cancelled without an undue delay when it has been used for certifying the origin of electricity disclosed as "produced from renewable sources". Electricity transmitted between countries included in the system of guarantees of origin is not accounted for when determining non-certified production. Instead, the residual mix will be adjusted later with the European attribute mix when necessary. The system's internal countries include EU states, excluding Malta and Cyprus, but including Norway, Iceland, and Switzerland.

The next step is to determine non-certified consumption, which is calculated by subtracting the number of cancelled guarantees of origin from Finland's electricity consumption. If non-certified consumption exceeds the volume of non-certified production, the deficit is filled with information according to the European attribute mix. If the volume of non-certified production exceeds non-certified consumption, the surplus is transferred to the European attribute mix, divided according to the national production mix. This means that the European attribute mix is formed by summing up the national surpluses and using that information as the basis for determining energy source percentages, average carbon dioxide emissions and the average amount of spent nuclear fuel.

Information sources used

The residual mix is calculated according to the best information available. On the basis of a partnership agreement signed with Statistics Finland, Finnish Energy Industries compiles production and fuel information on electricity production and the joint production of electricity and heat. The information is utilised at several stages of the calculation process. Russia's export and import volumes are obtained from the data service of the European Network of Transmission System Operators for Electricity. Information published by the International Energy Agency is used as Russia's production mix. The grid company Fingrid, acting as the registrar, provides a residual mix calculation with the necessary information on the exports, imports and cancellation of guarantees of origin.

Emissions and the volume of spent nuclear fuel

Carbon dioxide emissions are calculated on the basis of fuel consumption by electricity production, as announced by the Finnish Energy Industries. The emissions of the main fuel categories (oil, coal, natural gas, peat, wood and other bio fuel, other non-bio fuel) are determined according to the CO2 emissions factor provided by Statistics Finland for this purpose. Wood and other bio-based fuels are assumed to be emission-free in the calculation process. The amount of spent nuclear fuel is based on the amount of nuclear fuel consumed in Finland.


In the residual mix calculation process, it is essential to ensure that electricity from renewable sources is only accounted for once. To prevent double calculation, the Energy Authority adheres to the recommendations issued by the RE-DISS project in its calculation process, within the limits allowed by national legislation. The purpose of the RE-DISS (Reliable disclosure systems for Europe) project, promoted by the European Commission, is to support competent bodies and to improve the reliability of information supplied to customers on the origin of electricity. The project has drawn up a recommendation for the best practices concerning the guarantee of origin. The recommendation exceeds the level of regulation required by the RES directive. The calculation basis for the residual mix is determined in Section 8 of the Government Decree on Confirming the Origin of Electricity (417/2013). The Energy Authority uses the Transaction Based Method in the calculation process.  For more details, please visit www.reliable-disclosure.org.