The world-wide availibility of feedstock has to be taken into account if bioethanol from lignocelluloses is to contribute significantly to the world fuel market. A report by Bentsen & Felby (2010) shows existing agricultural residue of 1.6 Gt/year cellulose and 0.8 Gt/year hemicelluloses (figures do not include Africa and Australia). This gives a theoretical quantity of 1.24 Gm3 bioethanol from cellulose (690 l/1 using Saccharomyces spec.) and 0.480 Gm3 (600 l/t using Zymomonas spec.) from hemicelluloses. For comparison: the worldwide production of crude oil is estimated to reach not more than 4.8 Gm3 pa (83 million bbl/day) and is supposed/predicted to decline to under 2.4 Gm3 pa (41.5 million bbl/day) by 2040 (Zittel, 2010). The potential of bioethanol from agricultural residues seems to be high. But not all residues will be available and the conversion rates will not be 100%. Therefore, it is thought that lignocellulose-containing materials have to be produced on agricultural land possibly in combination with the production of feedstocks like wheat, corn or sugar cane. These crops would serve as feedstocks for bioethanol production of the first generation.

The yield per hectare is conservatively estimated at 3000 l and 1500 l per hectare of agricultural land for bioethanol of the first and second generation, respectively. A replacement of 41.5 million bbl/day of crude oil would require an area of land of around 5 million km2.

Using DDGS (distillers dried grain solubles) as protein-rich animal feed, taking into account an increase in productivity in agriculture and using intermediate crops as feedstock, the required area could be reduced to under 2.5 million km2. This represents approximately 3% of the world’s land (Bentsen & Felby, 2010).