Cellulosic ethanol blend successfully tested in Mercedes fleet
Speciality chemicals company Clariant, hydrocarbon-based product manufacturer Haltermann Carless and automaker Mercedes Benz have successfully tested sustainable cellulosic ethanol made from agricultural waste in a pilot project. The fuel, named sunliquid 20 for its 20% ethanol content, was used in a Mercedes Benz fleet over a year after being produced by Haltermann Carless using cellulosic ethanol manufactured in a Clariant plant. The fuel cuts GHG emissions by up to 95%, without competing for land with food production. Green Car Congress suggests that if E20 fuel is widely adopted, engines could be adapted, improving efficiency, and reducing fuel consumption and CO2 emissions.
The cellulosic ethanol allows greenhouse gas emission savings of up to 95% across the entire value chain without competing with food production or tying up agricultural land.

Clariant, a leading global specialty chemicals company, together with Mercedes-Benz and Haltermann Carless, a well-established HCS Group brand, tested the use of sustainable cellulosic ethanol from agricultural residues in a fleet test with Mercedes-Benz series vehicles over a period of 12 months for the first time in Germany. sunliquid 20 was used for the test—a fuel produced by Haltermann Carless with a cellulosic ethanol content of 20 vol% (E20) from Clariant’s sunliquid plant in Straubing.

The sunliquid process uses a bespoke enzyme mixture to hydrolyze cellulose and hemicellulose chains to form sugar monomer—i.e., saccharification. The enzymes are highly optimized based on feedstock and process parameters, resulting in maximum yields and short reaction times under optimal conditions.

Using optimized microorganisms, the sunliquid one-pot system simultaneously converts both C 5 and C 6 sugars to ethanol, delivering up to 50% more ethanol than conventional processes which convert only C 6 sugars.

Clariant has been operating a pre-commercial plant in Straubing, which produces up to 1,000 metric tons of cellulosic ethanol from around 4,500 metric tons of raw material every year, since July 2012.

At the Haltermann Carless production site in Hamburg, the bioethanol is mixed with selected components to form the innovative fuel whose specifications represent the potential for the quality of E20 fuel in Europe.

In the fleet test with Mercedes-Benz vehicles, sunliquid 20 exhibited very good combustion properties with a high degree of efficiency and identical consumption compared to today’s standard E10 fuel. Due to the slightly lower energy density of E20 compared to E10, slightly higher fuel consumption was expected under the same operating conditions. The tests performed under laboratory conditions demonstrated variability in the consumption analysis in which additional consumption between 0 and 3 percent was observed.

In addition to the performance, an improvement in particle count emissions by around 50% was measured for sunliquid 20 versus the EU reference fuel Euro 5.