Modelling of Emissions and Energy Use from Biofuel Fuelled Vehicles at Urban Scale

Daniela Dias,Oxana Tchepel,António Pais Antunes

doi:10.3390/su11102902

Abstract

Biofuels have been considered to be sustainable energy source and one of the major alternatives to petroleum-based road transport fuels due to a reduction of greenhouse gases emissions. However, their effects on urban air pollution are not straightforward. The main objective of this work is to estimate the emissions and energy use from bio-fuelled vehicles by using an integrated and flexible modelling approach at the urban scale in order to contribute to the understanding of introducing biofuels as an alternative transport fuel. For this purpose, the new Traffic Emission and Energy Consumption Model (QTraffic) was applied for complex urban road network when considering two biofuels demand scenarios with different blends of bioethanol and biodiesel in comparison to the reference situation over the city of Coimbra (Portugal). The results of this study indicate that the increase of biofuels blends would have a beneficial effect on particulate matter (PM2.5) emissions reduction for the entire road network (−3.1% [−3.8% to −2.1%] by kg). In contrast, an overall negative effect on nitrogen oxides (NOx) emissions at urban scale is expected, mainly due to the increase in bioethanol uptake. Moreover, the results indicate that, while there is no noticeable variation observed in energy use, fuel consumption is increased by over 2.4% due to the introduction of the selected biofuels blends.

Highlights

Today, oil-derived fuels account for around 94% of final energy demand in the transport sector and almost three-quarters is used by road transport [1]
The spatial variations in traffic flows that were obtained from the VISUM software and considered for traffic emissions estimation for the selected scenarios are presented in Figure 4, which correspond to about of 1,420,000 vehicle*kilometres travelled (VKT) per day within the Coimbra’s urban area
According to the results that were obtained through the developed QTraffic emissions model, the implementation of bioethanol, and biodiesel fuelled private cars leads to a global increase in nitrogen oxides (NOx) emissions, while there is no noticeable reduction being observed in atmospheric PM2.5 emissions for Coimbra (Table 4)

Summary

Introduction

Oil-derived fuels account for around 94% of final energy demand in the transport sector and almost three-quarters is used by road transport [1]. In order to promote the security of energy supply and a reduction of greenhouse gases (GHG) emissions, as well to help urban areas meet European Union (EU) air quality obligations, the European Commission has adopted the “Clean Power for Transport package”—a Communication laying out a comprehensive alternative fuels strategy for the long-term substitution of oil as energy source for transport [2]. Under this strategy, the adoption of alternative sources of energy, which include electricity, hydrogen, biofuels, natural gas, and liquefied petroleum gas (LPG), will play an important role in achieving the EU objectives. Motivated by European strategies, Portugal intends to meet the RED Directive goals for road transports using biofuels, where about 6.6% of road transport energy is expected to be biodiesel in 2020, and 2.2% to be bioethanol [6]

Objectives

Results

Conclusion