Quality variation in market biofuels and the effect on tailpipe emissions

Title : Quality variation in market biofuels and the effect on tailpipe emissions

Abstract:

Biofuels come in many different forms, with different chemical compositions and, consequently, create different emissions when they are burnt in an engine. Variations in chemical composition may be natural effects of the feedstocks within legal standards, or evidence of non-compliance.  Any effects of the biofuel on in-use fuel efficiency of a vehicle needs to be weighed against upstream carbon dioxide savings.

Variations in the quality of biofuels goes beyond technical compliance. Emissions Analytics and Oxford Indices collaborated to use two-dimensional gas chromatography and time-of-flight mass spectrometry to perform a comprehensive speciation of organic compounds on multiple samples of fuel sold as the same product in Europe; this was repeated across around five different fuels.  This technique allows advanced separation of compounds up to at least C44, identification of the compounds using specialist spectral libraries, and quantification using known standards.  From this, it is possible to quantify both the within-fuel variability and the between-fuel variability.

The fuel with the greatest variability between samples was then submitted to real-world, on-road testing in a vehicle using a Portable Emissions Measurement System (PEMS) adapted to also sample onto thermal desorption tubes.  The PEMS system records real-time quantification of regulated pollutants, while the desorption tubes give a detailed organic speciation of unregulated pollutants on an integrated basis.  Using these results, it is possible to show the effect on regulated and unregulated pollutants of the variations in the fuel in the engine.  From this, it is possible to conclude whether the fuel variations are material to air quality and greenhouse gas emissions, and whether that warrants any changes in fuel regulations.

Audience Take Away Notes:

• How consistent the overall chemical composition of biofuels on the market today are.
• Potential reasons for this variation.
• To what extent this fuel variation matters causes changes in tailpipe pollutant emissions.
• Suggestions for regulatory changes to improve quality and reduce emissions.

Biography:

Nick founded Emissions Analytics in 2011 to understand real-world emissions and fuel economy and emissions from vehicles. Its EQUA Index database of thousands of independently conducted tests is an international performance benchmark. The wider mission is to understand the holistic environmental impact of vehicles on air, soil and water, from tyre wear rates to volatile organic compound emissions. Nick is chairman of the European standardisation CEN Workshop 90 on collecting real driving emissions data, which has led to the publication of the AIR Index.  He is also chairman of CEN Workshop 103 on standardising the collection of vehicle interior air quality data. He is a specialist in data analytics, particularly in the automotive market, through his prior work at Oxford Indices Ltd, a data specialist, United Business plc and Haymarket Media Group. Nick is a graduate of the University of Oxford, and an Honorary Research Fellow at Imperial College London.