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 CO 2 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 CO 2 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. • Thermoelectricity's direct carbon emissions and water consumption estimates from 1969. • Uses real data per plant for CO2 and consumptive water use, extrapolating backwards. • Some small technological improvement to reduce emissions within generation technologies. • Carbon emissions and water consumption correlate over time in absolute levels. • CO2 per MWh halved while the water per MWh more than doubled since 1969. [ABSTRACT FROM AUTHOR]