Sunliquid® – Cellulosic Ethanol and Biobased Chemicals from Agricultural Residues (Germany)

Context of Transport Climate Action


The global population is facing multiple challenges. Reducing greenhouse gas emissions and dealing with a shortage of fossil fuels, while having to supply an ever- growing population with food and energy, are only some of them. Cellulosic ethanol, which is produced from agricultural residues, a resource globally available in high quantities within current agricultural practices, allows a significant reduction in carbon dioxide emissions when used as a source of fuel energy – without competing with food or for agricultural acreage in its production.

In the EU alone, according to Eurostat, around 240 million tons of agricultural residues are produced every year. Clariant, a world leader in specialty chemicals, has successfully developed an efficient and economic process, the sunliquid® process, for the production of cellulosic ethanol and sugars from agricultural residues such as wheat straw, corn stover or sugarcane bagasse. The sunliquid® process has proved to be economically profitable and progress has been made towards its commercialization. Meeting the target of about a quarter of European transport energy demand for gasoline in 2020 with advanced biofuels could be within reach.


Clariant’s entirely integrated sunliquid® process converts lignocellulosic agricultural residues, such as cereal straw, into cellulosic ethanol or other bio-based chemicals, in a way that is highly efficient, economic and sustainable. An integrated enzyme production, from the cellulosic material itself, results in very low enzyme costs, as it eliminates the need for additional formulation and transportation and makes plant operators independent from external suppliers. To achieve high yields based on the shortest possible reaction times, the choice of enzymes used is specifically adapted to each individual feedstock material and each set of conditions for processing. Clariant offers a one-stop solution that can be used flexibly to convert different feedstock materials available in any region and the process can be adapted to various plant conditions. The sunliquid® Process Design Package delivers the technological blueprint for commercial facilities to produce between 50 and 150 kt of ethanol per year. The biofuel obtained using this process is manufactured on an energy-neutral basis and, when used as a fuel in transportation vehicles, boasts greenhouse gas emissions’ savings of about 95% , compared to fossil fuels. Its production process is not in competition with food or feed production and the production costs can compete with those of first-generation bioethanol.

In addition to application in the transport sector, the technology offers a platform for conversion of agricultural residues into a range of chemicals for different industries and applications. For example, cellulosic ethanol can be converted into bio-Mono Ethylene Glycol ( bio-MEG) for the production of bio-based chemicals.


Picture: The sunliquid® process: with its focus on integration, sunliquid® is designed to achieve optimal efficiency (Photo: Clariant)


Today, Clariant has transitioned from technology development into commercialization of its sunliquid® process. Since July 2012 Clariant has successfully been operating a pre-commercial scale plant in Straubing, Germany and has established that the technology works on an industrial scale and on various feedstock materials, using well-designed and specific equipment. Various feedstocks from different regions such as wheat straw, corn stover and sugarcane bagasse, have been successfully tested at the plant. With an annual capacity of 1,000 tons (1.25 million litres), the pre-commercial plant converts approximately 4,500 tons of lignocellulosic feedstock per year. This unique approach in the biofuel industry to testing and implementing this innovative technological process has significantly reduced the future up-scaling risks involved and has created a blueprint for different commercialization and feedstock scenarios.

Together with Mercedes-Benz, one of the world’s biggest car manufacturers, and Haltermann, a leading producer of high-performance hydrocarbons, Clariant launched a twelve-month field test in January 2014, applying sunliquid® cellulosic ethanol in a high quality E20 fuel. The test vehicles, which were all Mercedes-Benz series vehicles that were not modified for this test in any way, have demonstrated the highest performance of fuel and engines. Due to its first-class combustion properties, it has been demonstrated that sunliquid® 20 – a premium-grade gasoline containing 20% cellulosic ethanol – significantly improves engine efficiency, compensating for its 4% less energy content, as compared to E10 . Moreover, particle emissions are reduced by 50% compared to the EU reference fuel EU5. In comparison to the use of fossil fuel for transportation vehicles, sunliquid® cellulosic ethanol saves around 95% greenhouse gas emissions, without being in competition with food and feed production.


The widespread biomass availability in itself offers significant potential for using cellulosic ethanol as a transport fuel. Taking into account the fact that engine and vehicle technology are also constantly developing, it is clear that cellulosic ethanol made from crop residues can guarantee a major contribution to more sustainable mobility in global terms. As a domestic liquid energy source, cellulosic ethanol reduces dependence on oil imports, generates income for the agricultural sector and creates new, green jobs with high potential for greenhouse- gas savings.

The production of cellulosic ethanol is almost climate neutral. Today, innovative technologies such as sunliquid® already enable about a 95% GHG emission reduction compared with fossil-based petrol. Further technological developments will make an entirely carbon- neutral cellulosic ethanol production possible. The use of non-edible residues avoids competition with food and feed resources, nor is additional arable land required for resource or production purposes. Hence, cellulosic ethanol is a new, domestic energy source, derived from a renewable resource that is available without the need for additional agricultural land.

Potential for scaling up

A sunliquid® plant with an annual capacity of 50,000 tons requires approximately 227,000 tons of straw. Assuming that at least 10% of the agricultural residues per ha can be used for conversion into cellulosic ethanol, this gives rise to an area of some 4,700 km², or a collection radius for straw of a good 35 km. The biofuel produced from this area is enough to operate a fleet of 62,500 vehicles for a year, yet with almost zero CO2 emission in its total balance – and without any additional investment in new fueling infrastructure.

However, for pioneering technologies like sunliquid® to effectively enter the market, a supportive, reliable framework needs to be in place to foster investment and ensure investors’ confidence. In an economy where resource efficiency and sustainability are becoming increasingly important, we need to use all available resources in the most efficient way. Through using agricultural byproducts for the production of biobased energy products, both food and fuel can be produced in synergy, while at the same time protecting the climate and the environment and contributing to green economic growth.

To ensure the transition from a fossil-based economy to a bioeconomy, we need to bridge the gap between research and market. First, we need support for the implementation of novel innovative and sustainable production processes. Reference plants are needed to demonstrate the competitiveness of biobased versus fossil fuel production. Secondly, a stable and investment- friendly political framework is needed. For example, in the field of biofuels, it is necessary to accelerate the implementation of the Directive EU 2015/1531 at member state level, and avoide indirect land-use change (iLUC) effects. Dedicated and binding support measures for the production of advanced biofuels made from lignocellulosic biomass are also considered crucial. Long-term planning reliability and investor security must be guaranteed by these measures ,which will help ensure the speedy market uptake of new, innovative technologies in this field. These actions are essential for the successful transition to a sustainable bioeconomy as a whole in Europe.

Selected references












Global, Mitigation, Passenger, Freight, Technology


Clariant Produkte (Deutschland) GmbH


Ines Hoenemann +49 (0) 89 71 06 61 - 320

"With the innovative sunliquid® process, the dependency on fossil fuels can be reduced and local fuel production promoted, because every plant can use residues in the immediate vicinity. This creates jobs and additional income in rural areas".
-Dr. Markus Rarbach
Head of Start-up Business Project Biofuels & Derivatives, Clariant