Electric mobility is playing every day a more significant role in our lives. It helps keep our cities less polluted and largely reduces emissions. It is possible to furtherly reduce these factors in several ways; for example, by freeing ourselves from the concept of a private vehicle and introducing mobility as a service. Fleets of electric vehicles could easily and economically satisfy mobility demands in our cities, while at the same time greatly reducing traffic and pollution. But how much exactly? Is it possible to estimate and optimize the design of a fleet of electric vehicles for minimal Green House Gasses emissions (GHG)?