A simplified method to assess the influence of the power generation mix in urban carbon emissions

The simple action of filling a glass of water at home generates a greenhouse gas emission elsewhere, because it is necessary to spend electricity to treat the water, make it potable and then pump it to the point of consumption. These daily activities, seemingly clean, need electric energy and they carry out a human-induced greenhouse gas emission. Generation of electricity has a significant effect on the inventory of emissions and environmental impacts due to the large differences in the power generation sources used. This paper aims to shed light on the methodological challenge and develop a necessary simplified methodology to illustrate the importance of the power generation mix in urban greenhouse emissions. The electrical mix is a figure that expresses the carbon emissions associated to the electrical power generation, so it is an indicator of the suitability of the sources used for electrical power production. The smaller the mix, the higher is the contribution of low carbon emission sources. The methodology is explained, applying it to Madrid, assessing the greenhouse gas emission per kWh of electricity generated. The proposed estimation covers emissions of CO2 equivalent (KgCO2eq), including the equivalence between each greenhouse gas and carbon dioxide considering a prevalence of 100 years.