Jul 13 2012
The result of a study carried out at the Universidad Politécnica de Madrid evidences that to use biodiesel reduces emissions of greenhouse gases.
A research group of the INSIA, a centre of R&D of the UPM, conducted a Life Cycle Analysis applied to the use of biodiesel on urban buses to analyze and quantify primary and fossil energy consumption. They also analyzed emissions of greenhouse gases. The results can be used to guide the application of government policies on environmental matters related to road transport.
The road transport industry has a high influence in environmental impact since it growth has provoked depletion of fossil energetic resources (as petrol and natural gas) in the last years apart from provoking a high generation of emissions of greenhouse gases (carbon dioxide is an important emission). Due to this problem, they are currently researching alternative fuels as new technologies of pot-treatment of exhaust gases.
Biofuels are an alternative of high interest to resolve this problem. For example, biodiesel1 comes from renewable resources such as vegetable oils, animal fat or used cooking oils. In terms of technologies of post-treatment of exhaust gases, the research is mainly focused on two areas: selective catalytic reduction with urea (SCR+Urea) and the recirculation of gas exhaust gas with particulate filter (EGR+DPF).
In this context of biofuels and technologies of post-treatment of exhaust gases in the road transport industry, researchers carried out a Life Cycle Analysis about to buses belonging to the Municipal Transport Company of Madrid, each bus had technology of post-treatment of exhaust gases which was combined with the use of three types of fuel: diesel, B20 (20% biodiesel and 80% diesel) and B100 (100% biodiesel).
The main results found that the use of this type of fuel reduces emissions of greenhouse gases, but primary energy consumption is increased. However, only a small percentage of this energy corresponds to fossil energy since biodiesel is produced from non fossil resources such as oil plants or animal fats. Likewise, they observed an increase in nitrogen oxides emissions and a reduction in particles, and whose tendency is to grow with the increase of the mixture.
The total fossil energy consumed by the use of biodiesel is the result of crop processes and transesterification. Therefore, crop processes have to search for alternatives to reduce the consumption of fertilizers and this requires a considerable amount of fossil energy in their production, and transesterification has to implement cogeneration systems using renewable energy sources in transesterification plants to increase energy efficiency.
These results can be used as indicative information to implement government policies in terms of environmental issues related to intercity road transport in Spain. These results provide extracted information from extensive review of a bibliography and from databases known by the scientific community such as GEMIS or GaBi 4. The last community mentioned carried out an upgrade of energy balances, mass and emissions of the relevant process analyzed in this research.