Evolution of NO_x and SO₂ emissions in Spain: Ceilings versus taxes

Even though significant NO_x and SO₂ emissions reductions have been observed in Spain during last decade, there is a strong commitment to keep reducing the levels of pollution in order to improve air quality standards. This work has been carried out to ease the lack of National Emission Ceilings Directive (NECD) assessments at country level. The Spanish case has been used as illustrative of the European Union. The evolution of NO_x and SO₂ emissions has been analysed in depth using the TIMES-Spain energy optimisation model. The work has been structured into three parts. First, the implementation of the NECD and the consequences both on the evolution of NO_x and SO₂ emissions, and the electricity production mix; second, taxation on these pollutants has been modelled and discussed; and finally, the proposed "2013 EU Clean Air Package" ceilings to update NECD have been assessed. Results showed that meeting NECD targets would involve a high contribution of renewable sources to the electricity system, mainly wind and solar. In addition, NO_x and SO₂ taxation has been assessed. Results showed that taxes on pollutants led to lower emissions than using NECD. Hence, current ceilings are not strict enough to internalise all the environmental damages associated to those pollutants. In consequence, the suitability of the NECD has been discussed by means of the new ceilings included in the EU Clean Air Policy Package. Results showed that proposed reductions are insufficient to compensate the environmental damages especially in the short term.