Coal stands out among primary energies with the greatest progress since the year 2002, although it fell by 12% in 2006. These variations in such a short period of time can be partly explained by the fact that this energy, besides being used mainly for the generation of electricity, currently complies with a support mission for energies whose entry into the system is guaranteed: nuclear and renewable energies. The fall in nuclear production in 2007 (caused mainly by the programmed close of various nuclear power stations, occasionally for months) and the reduced price of the tonne of CO₂ were factors that favoured this behaviour.

In primary energy in Spain, oil has maintained a share of around 50%, with a reduction of only a few tenths of a point in recent years. Second position has been taken up by natural gas for four years. Nuclear energy provided 10% of the energy consumed in 2007, although mention must be made of the fact that this energy falls by an average of around one point each year.

And, with regard to renewable energy sources, of every 100 energy units consumed in Spain in 2007, 6.9 now come from this type of resource. This ratio is on the increase, although it is subject to the varying rainfall on the Iberian peninsular, as well as wind variability. For example, on 19 March 2007, the highest ever level of wind energy production was reached, setting a record of 8,375 MW, a figure that was exceeded halfway through January 2008 with a level of 9,550 MW. Together with these notable records (the latter equivalent to the production of almost 10 standard nuclear power stations), other levels of between 1000 and 2000 MW or even lower were also recorded.