Research Proves that High Ethanol Content Increases Fuel Consumption

A new study, conducted by VTT Technical Research Centre of Finland as a part of a TransEco research program, points out that commercial petrol grades such as 98E5 and 95E10 that are distributed in Finland do not make any significant difference in fuel consumption under driven normal conditions. The study, conducted under laboratory conditions, utilized six different models of used cars to prove the result.

During the tests, cars that used 95E10 ran 100 km using 10.30 liters, while cars that used 98E5 ran 100 km using 10.23 liters, showing a difference 0.07 liters in favour of 98E5. In other words, the 95E10 with its higher level ethanol content has increased fuel consumption by 0.7%. After assessing the results of each test run, total work performed during the driving cycle resulted in higher overall variation of 1.0%. The evaluation of calorific value of the fuel was 1.1% favoring E5.

To maintain the validity of the tests, VTT bought all the fuels needed for the tests from Espoo-based Otaniemi Neste Oil service station and ensured that the two batches of fuels have the required ethanol contents according to the specifications of the Finnish Customs Laboratory. The tests results indicated E5-grade with 4.7% ethanol content and E10 grade with 9.4%. Various models of cars manufactured between 1999 and 2010 were used in the tests and the cars were checked thoroughly prior to the tests for defects and malfunctions that can impact the test results.

Two tests were carried out on successive days for each type of petrol grade. The FTP72 driving program, which has faster accelerations and more than average speed, was used for the test drives. Two drivers, who were qualified to perform such tests, drove the cars. VTT measured the fuel consumption accurately by calculating the weight of fuel used during the tests.