Basics Bioplastics vs.
Basics Bioplastics vs. Agricultural Land Calculations, estimates, assumptions and conclusions How much bioplastics do I get from agricultural land? How much bioplastics can be obtained from 1 hectare of land? Differ ent figures are available to answer this question. We look at just three bioplastics as examples. PLA: There is a lot of confusion about the amounts of bioplastics that can be obtained from a given quantity of agricultural crops, and how much of these agricultural crops can be harvested from a given agricultural area. And last but not least: Is there enough agricultural land available to grow crops for bioplastics? This article can be regarded as a first attempt to shed some light onto this confusion, although the considerations are very much simplified in order to arrive at an initial overview. As with other articles in this „Basics“ section of bioplastics MAGAZINE, experts in the aspects discussed here are expressly invited to share their knowledge. Please contact the editor. We will assemble all of the information received and present an update in one of the following issues. Sources [1] FAQ at www.natureworksllc.com [2] University of Nebraska (www.ianrpubs. unl.edu/epublic/pages/publicationD. jsp?publicationId=144) [3] Personal information, Erwin Vink, NatureWorks [4] The Concept of Novamont‘s Biorefinery integrated in the Territory, Catia Bastioli, Novamont, Brussels, Nov. 2006 [5] National Corn Growers Association (www.ncga.com/CYC/Winners/national.asp) [6] Fachagentur nachwachsende Rohstoffe, brochure: „Bioplastics – Plants, Raw Materials, Products“ (www.fnr-server.de/pdf/literatur/pdf_237bioplastics2006.pdf) [7] Personal information, Brian Igoe, Metabolix [8] D. Bockey, UFOP, based on information from the Bayerisches Staatsministerium für Landwirtschaft und Forsten (in Bioenergie - ein Markt der Zukunft, TTL Jena, A. Vetter, 2006) [9] www.european-bioplastics.org The FAQ page at natureworksllc.com reports that on average, approximately 2.5 kg of corn (15% moisture) are required per kg of PLA. This does not mean that the difference (1.5 kg corn) is all waste. A part of this difference is simply water, a part of it ends up in other corn wet mill products such as germ oil, corn gluten meal and corn gluten feed, and part represents the yield losses in the different processes [1]. Depending on the geographical location and whether a field is irrigated or not, the yield of corn per hectare differs significantly. Yields vary from 60 bushels/acre (3.7 tons/hectare) from Western Nebraska dryland [2] through 148 bushels/acre (9.3 t/ha) as the average corn yield in the USA in 2004/2005 [3] and 12 t/ha in Europe [4], going right up to 332 bu/acre (20.7 t/ha) reported from the National Corn Yield Contest in the USA 2006 [5] If we take the US average in 2004/2005 we can calculate an average “yield“ of 3.72 tons of PLA that can be “harvested“ from one hectare of land. Other sources report approximately 2 tons [6] or 2.5 tons [1] of PLA per hectare. è PLA: Approx. 2-3.7 tons / hectare PHA: Metabolix report that currently corn is the major source for their PHA. For 1 kg of PHA approximately 4.66 kg corn is needed [7]. Based on the information on corn yield above (average 9.3 t/ha), it is clear that about 2 tons of PHA per hectare can be harvested. è PHA: Approx. 2 tons / hectare MaterBi: MaterBi by Novamont [4] is a bioplastics material based on starch derived from corn and oils (derived in turn from oilseeds). Approximately 0.5 kg of corn and 1.4 kg of oilseeds, plus other components and additives, are needed to produce 1 kg of one example formulation of MaterBi. Given the corn yield of about 12 t/ha and a vegetable oil productivity of 1 t/ha [g] Novamont calculate a yield of approximately 2.5 tons of an average of different MaterBi resins that can be harvested from one hectare. è MaterBi: Approx. 2.5 tons / ha 36 bioplastics MAGAZINE [02/07] Vol. 2
Basics Photo: Novamont How much agricultural crop land is available? We will start with some basic figures. The total land area of this planet is about 13 billion hectares. The usable agricultural and silvicultural (forestry) area is about 5 billion hectares and agricultural crop land is given as approximately 1.38 billion ha [8]. The remaining question is: How much of this can be used for the production of agricultural crops for bioplastics? Here are some figures as a general indication: It is known that in many countries of the world a certain amount of agricultural crop land is not permitted to be used for food production, because the overproduction of food leads to an “imbalance in market prices“. In Europe the Common Agricultural Policy therefore has required the establishment of so called “set-aside zones“ where food products must not be grown. This measure is aimed at reducing the high level of agricultural subsidies in Europe. European Bioplastics estimates the available area for non-food production in the European Union (EU27) at around 20 million hectares [9] Based on the figures above this is enough for 40-50 million tons of bioplastics. So even if bioenergy, bioethanol and biodiesel to power our cars, and other chemical intermediate products, require agricultural crops there should be enough agricultural land available for the production of bioplastics. And bioplastics can after their material life be recovered by e.g. incineration, which gives a “double dividend“ from the respective agricultural resource. Both in ecological as well as in economical terms, bioplastics should therefore be a very favourable way of making use of agricultural commodities. In addition to this, it should be mentioned that we have discussed only primary agricultural crops here. However, developments are under way to create bioplastics from secondary biomaterial such as straw, stems and leaves, and even from municipal waste water. In this respect, it is interesting to consider the situation in the U.S.: The full capacity of NatureWorks‘ PLA plant of 140,000 tons per year needs only about 0.14% of the total corn produced in the USA. How much bioplastics will be needed? Latest figures say that the annual global production of all plastics today is about 240 million tons. If estimates that say about 10% of all plastics could be replaced by bioplastics are correct, this would amount to 24 million tons. For these 24 million tons, according to the figures above, agricultural crop land of approximalety 10 million hectares would be needed. This is 0.7 percent of the global agricultural crop land or 50 percent of the European set-aside zones - which are not even being used for food production. bioplastics MAGAZINE [02/07] Vol. 2 37
