In the context of the 22nd Conference of the Parties of the United Nations Framework Convention on Climate Change (COP22), Portugal announced that it would become carbon neutral by 2050. The Portuguese transport sector accounts for 16.2 million tons of greenhouse gases (GHG) emissions, approximately 23.3% of the country total. Most sector emissions are from road transport (96% of the transportation emissions), with the remaining share associated with other mobility forms (i.e. aviation, railways and navigation). The transport sector represents approximately the same level of emissions as power generation. Road transport is considered one of the sectors where full decarbonisation is technically possible. The objective of this work is to present the approach, methods and results of cost-effective pathways configurations to full decarbonisation of the transport sector till 2050 in Portugal. Four different scenarios were defined considering distinct national socio-economic future configurations and mobility trends (i.e. autonomous vehicles and sharing schemes): 1) Reference scenario; 2) Life is a highway scenario; 3) Thunders-Truck scenario, and 4) Country-roads scenario.
The technological linear optimization model TIMES_PT was used to evaluate the future penetration of different cost effective technological mobility options in each scenario. The TIMES_PT model represents the energy system of Portugal and its possible long-term developments. The model incorporates a high number of modern technologies related with the different components of the energy systems. They are characterized in terms of technical (ex. efficiency, lifetime) and economic (ex. investment and operation costs) features. The mobility demand for each scenario was defined with a bottom-up approach, considering urban and peri-urban transport conditions, smart city expected developments, and impacts of mobility megatrends. An evaluation of the various determinant factors of the energy transition in the mobility sector, and the strategic proposals to achieve the decarbonisation targets are presented. A mix of technological innovations, electric mobility and the generalization of shared mobility solutions, were identified as key factors to attain sector deep-decarbonisation. A combination of these trends with soft mobility modes and adequate policy and planning will enable the reduction of the transport carbon footprint, while providing a better and more equitable access to mobility. In the freight sector, new railroads based in electric traction, and autonomous trucks supported by new road electric infrastructure, can provide a more efficient and decarbonised pathway. Hydrogen powered solutions will also play a key role.
The transition to a decarbonised mobility future should be carefully planned to avoid investments that can lock-in mitigation objectives. Reducing GHG from mobility supply, will be a function of three components: renewable sources based electrical grid, use of hydrogen produced from renewable sources, and new zero emission synthetic fuels. A strategy to achieve an almost-total decarbonisation of the transport sector in Portugal can indeed be implemented. It will be both a viable and cost-effective mix of technological and behavioural components. Further developments will be made to assess the significance of the designed mobility decarbonization pathways in the context of the sustainable development goals in an European context.
Keywords: Mobility; Decarbonisation; Zero-emissions; Cost-effectiveness; Consumer behaviour
6c. Infrastructure and transportation
