Environmental and energy assessment of new vehicle technologies in the greater Athens area

Abstract

The transport sector in Greece has the largest share in the final energy consumption and thus a great potential for energy savings. The resulting emissions are also one of the main sources of atmospheric pollution. This situation is worse in the prefecture of Attica, where almost half of the country’s private cars circulate in an area equal to the 3% of the total country area. Gasoline and diesel fuels are used almost exclusively in present internal combustion engines. The low efficiency of these engines, the environmental problem caused by cars and the limitation of fossil fuels are demanding new engine technologies and new fuels. This paper examines energy saving and environmental impacts reduction from the penetration of eco-friendly technology passenger cars in the Greater Athens Area. Three vehicle technologies are considered: (i) conventional hybrid electric vehicles, (ii) battery electric vehicles and (iii) fuel cell electric vehicles. The displacement of gasoline consumption largely depends on the level of penetration of new technologies in the vehicle fleet. The hybrid and battery electric vehicles have already been introduced in the market but their share is still low. On the other hand, fuel cell vehicles still need more improvement before their commercialization. For these reasons, two alternative scenarios are formulated. The first one involves the substitution of all the passenger cars that were registered during the last year (2010) with hybrid and battery electric vehicles that already exist in the Greek market. The second scenario examines the penetration of fuel cell electric vehicles. For the purpose of this analysis, a number of fuel cell vehicles are designed that satisfy common performance requirements, similar to the existing cars. A parametric vehicle energy consumption model has been adapted for the analysis. The share of registered passenger car technologies and the annual vehicle kilometres for the study area are taken from literature data sources. Two different driving cycles, the New European Driving Cycle and the Athens Driving Cycle are used and the results are compared. The sizing of fuel cell vehicle components is achieved using a vehicle design model, on the basis of input performance constraints. Both scenarios are evaluated on the basis of their expected energy savings and greenhouse gas emissions reduction. A 5% to 7% reduction of the CO2 emissions is expected if these measures are applied in a five year period.