The adoption of renewable energy sources towards more sustainable urban transport systems. A case study on the city of Athens

The present study was prepared as an M.Sc.Thesis for the postgraduate studies program “Environment and Development” of National Technical University of Athens (NTUA). Urban transports, both individual or mass transports and transportation of goods account for a large proportion of annual energy consumption per capita not only within the city’s limits but on a national scale. In all big cities the current urban planning trends promote the adoption of clear energy, the installation of systems exploiting renewable energy sources and new technologies for energy saving and recovery. Both the urban mass transports operators and the citizens are encouraged to adopt these policies on a different extent, but with the same ultimate goal, the gradual electrification of the network. The goal of the study is to summarize the available techniques and technologies in vehicles used in urban transports and relevant infrastructure adopting alternative energy sources along with various environmental aspects which apply to the complex urban environment as well as mentioning the various strategies involved such as the decarbonisation and the sustainable urban mobility plans. The second part of the study focuses on the Attica region which includes Athens and its greater suburbs zone. Athens is the capital of Greece and can be easily classified as a metropolis not only by the population of residents which is almost 4 million but also with the area occupied and is suffering from severe atmospheric pollution problems caused to a great extent by the aged fleet of personal cars and the fleets of urban transportation. Therefore it was deemed a perfect testbed to study how the current status could be affected by interventions such as new vehicles and infrastructure upgrades along with policies aiming to electrify part of the public transports road network, increase the renewable energy yield in the transport grid, adopt state-of-the-art technologies to cut energy consumption and retrieve it back. Three separate scenarios regarding implementation of solar energy systems are explored and their benefits are evaluated using several assumptions. These steps along with plans and policies to encourage citizens to use public transport regularly, in combination with non-polluting means of transport such as bicycles or light electric vehicles can effectively reduce carbon emissions, achieve a more sustainable urban environment, and lead the way to reducing our general environmental footprint towards a net zero-footprint.