Towards international measurement standards for biofuels
There is an increasing demand to accurately measure the quality of biofuel products (biodiesel and bioethanol), particularly in view of European directives promoting renewable energies and setting out quality requirements for fuel. Until now, there has been no international consensus on the technical specifications of biofuels. Nor has it been fully clear what measurement standards and quality control tools in form of reference materials are needed to meet legislative requirements.
BIOREMA (REference MAterials for BIOfuel specifications) was an international project on biofuel reference materials involving JRC's Institute for Reference Materials and Measurements (IRMM) which recently published its final results. The project demonstrated that it is feasible to prepare biodiesel and bioethanol reference materials with reference values traceable to the international system (SI) of units for a range of parameters. However, further research is needed for several parameters such as for glycerides in biodiesel and acidity in bioethanol.
The project also carried out inter-laboratory comparisons using biodiesel and bioethanol test materials prepared throughout the project. The exercise showed that the measurement capabilities of the field laboratories were often good in the case of biodiesel, although the availability and use of certified reference materials will certainly enhance the comparability of measurement results for many parameters. For bioethanol, the consensus values for density, ethanol and water were in very good agreement with the reference values. However, several other parameters, such as, electrolytic conductivity and acidity, exhibited poor measurement reproducibility.Overall, there is a pressing need for (certified) reference materials to improve measurement reproducibility.