peer reviewed ; In the context of sustainable development, the environmental aspects of urban areas are taken into account by correlating them with their energy consumption. The purpose of this research is to collect and analyze the energy consumption data due to the transport in Belgium, and more precisely in the Liege province. But, also to make forecasts of these same consumptions to the horizon 2030-2050. The methodology chosen allow to model and improve the energy consumption for city-wide transport and to forecast the evolution of city energy consumption to simulate the effects of some urban development strategies. We focus here on the city of Liege and we will compare the different data of energy consumption with those of other cities. The analysis of the impacts of mobility on energy consumption and greenhouse gas was based on seven scenarios established through several surveys and research studies. The results showed that the daily mobility of inhabitants has a significant effect on CO2 emission and energy consumption. It is necessary to act in the long term by encouraging public transport such as vehicles with low energy consumption. The energy consumption in transportation sector can decrease up-to 19%, by reducing between 10% and 20%, of displacement by private car, and an increase up to 60%, both combined displacement by bike (for the distances small than 12 km), and walking (distances small than 1km).