ENTSOG has applied a simplified methodology with country granularity. This methodology is based on the assumption that some of the sources used to generate electricity show low sensitivity to market conditions. In the case of nuclear energy, generation is mainly base load, while for renewables like hydro, wind or solar, the generation mostly depends on the availability of the driving sources. The contribu- tion of other sources such as gas and coal 1) is mainly driven by the relative fuel prices.
1) This would also apply to oil-derived fuels. Given the marginal role of such sources in the European generation mix they have been considered fixed. The only exception would be Estonia, where the split of the thermal gap is done between gas and oil.