Governments around the world have created national targets for substituting fossil fuels and petro-based materials by biofuels. EU has set the target to 10% biofuels share for the transport sector by 2020 (EU directive 2009/28/EC). A major concern with liquid biofuels for the transportation sector is the sustainability of such fuels with respect to actual GHG reduction potential, land-use-change issues, and biomass availability. Secondly, cost competitiveness with current fossil fuels is a major barrier for deployment of current technologies for production of biofuels. The environmental and economic sustainability of producing liquid biofuels is largely dependent on the feedstock used for the process.

Feedstock’s that are easily processed into biofuels are the 1st Generation (1G) feed stocks such as oil from oil crops, sugar cane juice and starch from cereal grains, but these feed stocks have a high price and are challenged with the environmental sustainability and the food versus fuel dilemma. 2nd Generation (2G) feed stocks such as wood, wheat straw, corn stover, herbaceous crops and food and paper/cardboard waste have a lower price, are abundantly produced, and are sustainable to use as biofuels feedstock as it is CO2 neutral and does not compete with food production.

In the FLEXI-GREEN FUELS project, we aim to advance the production of next generation liquid biofuels for shipping and aviation by developing and improving integrated technologies for a complete conversion of 2G types of feedstocks: Lignocellulosic residue biomass focusing on wood waste from forest industries and sawmill wastes and agricultural residues (LIGN) and the organic fraction of municipal waste (OFMSW). In this way, all major types of 2G biomass resources available for biofuels production will be addressed.

Semi-continuous organosolv pretreatment process will be used for the separation of the cellulose and hemicellulose fractions from lignin, aiming at the most efficient conversion of each stream. As lipids are far superior bio-crudes towards hydrocarbon fuels, the intermediate conversion of sugars (being abundant in LIGN and OFMSW) to lipids will play a key role in the proposed integrated technology.

In this project, three efficient methods to convert sugars to lipids will be developed (fungal fermentation, algae dark fermentation, and lipid rich larva production) which will be further converted via advanced hydrotreatment (HDO/isomerization) processes to diesel range (C16-C18) alkanes and will be optimized for aviation or shipping fuels. We will combine this with the utilization of furans (from pentose/hexose sugars) via condensation and hydrogenation routes to allow production of drop-in aviation fuels (C8-C17), as well as with the utilization of lignin fast pyrolysis oil via selective fractionation, hydrogenation and alkylation towards aviation and/or bunker like fuels (>C18) – enabling efficient and feasible conversion of all biomass fractions.

Common for sugar and lipid routes to aviation fuels is that they usually require hydrogen to remove oxygen from the bio-molecules and replace with hydrogen to form saturated hydrocarbons (by hydrogenation). Hence, sustainable production of hydrogen will also be a key part of the whole technology.

The FLEXI-GREEN FUELS project will not only optimize the individual processes that go into the overall concept, but show profitable liquid biofuel processes with great flexibility and many possible options for implementation.The project will help to solve the problem of utilization of OFMSW and LIGN and support forest, agricultural, and municipality waste-industries with additional value creation and jobs in the industry using the principles of green circular economy while increasing feasibility in the production of low GHG footprint, renewable fuels, and valuable side-products.


This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 101007130.