At the crossroad between green and thirsty: Carbon emissions and water consumption of Spanish thermoelectricity generation, 1969-2019

The energy sector is the main contributor to greenhouse gas emissions and one of the thirstiest sectors worldwide. Within the energy sector, thermoelectricity directly impacts on both emissions and water. This study assesses the evolution of the direct CO2 emissions and operational water consumption of the Spanish thermoelectricity generation from 1969 to 2019. Both carbon emissions and water consumption correlate over time, led by the trends in total thermal generation, although over the past half century, water requirements swelled far more than carbon emissions. This results in a long-term trade-off between carbon emissions and consumptive water use in relative terms: while the CO2 per thermal MWh generated halved since 1969 in Spain, the operational water consumption per MWh of thermoelectricity generated more than doubled due to switching from coal burning to nuclear and combined cycle technologies. We find no real trade-off in absolute levels. Although moving towards smaller environmental impacts since the mid-2000s, thermoelectricity remains one of the largest carbon emitters while becoming one of thirstiest energy technologies in Spain.