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From Science & Research

From Science & Research Article contributed by Toby Heppenstall, Lucite Intl., Southampton, UK The availability of fermentable carbohydrate as a feedstock for bio-based platform chemicals and bioplastics Price [€/t] Many chemicals and plastics manufacturers are beginning to consider the opportunities presented by Industrial Biotechnology; the biosynthesis of bulk and fine chemicals mainly by fermentation processes from renewable agricultural feedstocks. Due to the widespread commercial interest in bioethanol, much has been written about feedstock type and availability forecasts. In general however, studies have estimated feedstock quantities by computing ‘necessary amounts’ from demand-side projections. A new study by a manager in the chemical industry attempts for the first time to derive a supply-side view of the availability in Europe of fermentable feedstocks for the biosynthetic industries. Quantitative results are provided by two models developed for the study. The first is an interactive model of potential surplus cereal supply (including straw) based on gross shifts in population and land usage. The second is a supply curve for Miscanthus, a potential ‘energy crop’ feedstock for second generation lignocellulosic fermentation. The Miscanthus supply curve is based upon a cost model over the whole production cycle (perennial grass crops have very different economics to annual arable crops). Input variables include the opportunity cost of land in different parts of Europe, and critically, the achievable yield on €160,00 € 120,00 € 80,00 € 40,00 2.36m ha € 0,00 0 50.000 Figure 1, Supply curve for Miscanthus in Europe, with lower section magnified. Price [€/t] € 80,00 € 70,00 €60,00 Supply Quantity / ktes € 50,00 30m ha 2.36m ha 2.36m ha € 40,00 0 10.000 20.000 30.000 40.000 50.000 Supply Quantity [t] different qualities of land 1 . The resulting minimum entry price for cultivation in each region can be plotted against cumulative quantity resulting in a supply curve as below. The supply curve derived is consistent with the current situation. With current prices just above €40/t, the maximum that can afford to be paid by the power generation industry, it is unsurprising that little more than ‘research and development’ quantities have been brought into cultivation in Europe. This result also provides independent support for the commonly held view that in the current paradigm at least; Miscanthus has the potential to become a minor crop but not a leading agricultural commodity. To make predictions, these models must be placed in some sort of context. The majority of platform chemicals relevant to bioplastics will be produced by fermentation and as such only fermentable feedstocks were the subject of this study. However, the economic driver for the sector will be the production of liquid transport fuel. The lion’s share of output from biorefineries will be biofuels. Therefore the mix of feedstocks available to fermentation buyers will be determined by the optimum input for the biofuel production process that becomes dominant, whether or not this process is fermentation. Framing the uncertainty in this way sheds light on the issue from the perspective of technological evolution. Recognising that industrial biosynthesis is in a period of intense and uncertain technological upheaval, a battle for dominance is underway. The key defining element for all players is the dominant design of the fuel biorefining process and the widely accepted theory of dominant design postulates that only one of these processes will ultimately prevail. Using this insight, three plausible scenarios are derived, based on the mutually exclusive dominance of either 2nd generation (lignocellulosic) ethanol, 2nd generation biodiesel (derived from a 36 bioplastics MAGAZINE [01/09] Vol. 4

From Science & Research low cost and low impact oil such as algae), and thermodynamic syndiesel. A fourth scenario of low oil price was also considered, in which progress to ‘2nd generation’ technology biofuels is entirely absent. Principal Biorefinery Process Crude Price HIGH LOW Fermentation Dominant ‘Gasohol’ Scenario Esterification Dominant ‘The Algae Age‘ Scenario ‘Technology Stagnation’ Scenario Thermochemical Dominant ‘Synfuels’ Scenario Figure 2: Interplay of the three Critical Uncertainties in the scenario structure The econometric models are then tailored to each scenario: For example in the gasohol scenario, the vast demand for carbohydrate for fermentation would drive increased supply of both 1st generation (starchy) and 2nd generation (grassy) crops. Assumptions are made for incorporation into the supply models, about resulting shifts in land availability and usage, and government policy support for growers in this context. The resulting output suggests that an aggregate supply of between 43 and 175 million tonnes (depending on the scenario) of fermentable carbohydrate 2 is feasible. These quantities represent an equivalent amount of ethanol to replace between 7 and 20% of all transport fuel and would be sufficient to supply likely total demand for bio-bulk chemicals, between eight times and forty times over. SCENARIO Miscanthus Straw Surplus Cereal Others-Sugar Others - Ryegrass Total ‘Gasohol’ 89.7 M 55.7 M 25.7 M 9.3 M 180.4 M ‘Algae Age’ 55.7 M 13.6 M minor 68.8 ‘Synfuels’ 20.9 M 55.7 M 13.6 M 90.2 M ‘Tech Stagnation’ 22 M 21.7 M 43.7 M Figure 3: Total Supply of fermentable carbohydrate (not tonnes of commmodity) in each scenario As a digression it is interesting to consider the maximum purchase prices that might be feasible for Miscanthus, depending on the relevant end-use industry in the different scenarios; bioethanol, bio-bulk chemicals, and thermochemical. Theoretical price points can be derived from the market price of the relevant end-product, taking account of total production cost in each case and the cost proportion of the feedstock. Price points are overlaid as ‘demand functions’ on the Miscanthus supply curve as below: Price [€/] €100,00 € 90,00 € 80,00 €70,00 € 60,00 € 50,00 € 40,00 € 30,00 0 10.000 20.000 30.000 40.000 50.000 60.000 70.000 80.000 90.000 100.000 Supply Quantity / kt Poss Price for Bulk Chems Figure 4: Supply curve for Miscanthus in Europe with price points Max Price for Bioethanol (benchmark current ethanol) Max Price for Thermochemical (benchmark diesel, oil at 6/bbl) Max Price for Bioethanol (benchmark petrol, oil at 6/bbl) Price to POWER Industry Other conclusions from the MBA thesis as well as a list of references can be found at 1: The author is indebted to John Clifton Brown of IGER, Aberystwyth UK for sharing raw yield data of Miscanthus for all NUTS2 administrative regions in the EU. Cultivation cost data is based on primary research with Miscanthus producers in th UK in 2008. 2: Note the unit mass of fermentable carbohydrate. Different feedstock crops have different carbohydrate content. The assumption is made that 1 tonne of plant carbohydrate (Starch, cellulose, or hemiocellulose) yields 1 tonne fermentable sugar (glucose, sucrose, dextrose, xylose), which is a little crude but holds theoretically true. The author is not an economist nor a professional research scientist. This article summarises an MBA thesis which drew on the body of existing literature on industrial biosynthesis as well as primary research with supply-side industry professionals. The analysis is original. The author’s intention is to add information and stimulate discussion in the area, not to claim absolute accuracy. bioplastics MAGAZINE [01/09] Vol. 4 37

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