Recent droughts and heatwaves showed the vulnerability of the electricity sector to surface water constraints with reduced potentials for thermoelectric power and hydropower generation in different regions. Here we use a global hydrological-electricity modelling framework to quantify the impacts of recent drought and warm years on hydropower and thermoelectric power usable capacity worldwide. Our coupled modelling framework consists of a hydrological model, stream temperature model, hydropower and thermoelectric power models, and was applied with data of a large selection of hydropower and thermoelectric power plants worldwide. Our results show that hydropower utilisation rates were on average reduced by 5.2% and thermoelectric power by 3.8% during the drought years compared to the long-term average for 1981–2010. Statistically significant (p < 0.01) impacts on both hydropower and thermoelectric power usable capacity were found during major drought years, e.g. 2003 in Europe (−6.6% in hydropower and −4.7% in thermoelectric power) and 2007 in Eastern North America (−6.1% in hydropower and −9.0% in thermoelectric power). Our hydrological-electricity modelling framework has potential for studying the linkages between water and electricity supply under climate variability and change, contributing to the quantification of the 'water-energy nexus'.