Costs of ethanol production from sugarcane in Eastern Batangas [Philippines]

Three major energy-and monetary-using stages in ethanol production from sugarcane were analyzed; cane production, cane processing and distillery operation, and distillery slop disposal. Storing, hauling, storage and distributing ethanol to gasoline stations and mixing also consume energy, but they were not included in this case study. Of the three main stages in ethanol production, cane production (the substrate) consumed the highest energy at 76.66% (12.61 LDOE/TC),processing/distilling at 10.75% (1.717 LDOE/TC) and applying distillery slops in the field at 12.88% (2.12 LDOE/TC) or a total of about 16.45 LDOE/TC (26.31 L ethanol/TC). The energy balance (Ee) of ethanol production from sugarcane, while positive, is generally low at Ee=2.53. This means that for every 1 unit of non-renewable energy spent about 2.53 units of renewable energy are produced(4.05 L of ethanol). The substrate cost is shown to be both the monetary and energy cost driver of ethanol production at 67.7% and 73.44% of the total costs, respectively. Gross ethanol yields per tonne cane range from 54 to 82L/TC. This is attributed to the wide range of fermentable sugars (9 to 13% sugar content). In general, a 1% increase in sugar content of the cane increases ethanol yield by 10%. In turn, increasing ethanol yield per tonne cane also improves the energy efficiency. For every 1% increase in sugar content, the energy efficiency increases by 12%. At 11% sugar content and 80 TC/ha about 3,746 L/ha ethanol yield can be obtained. Using this average figure, about 158,000 ha is needed to produce the 594 mL of ethanol needed by 2011 under the Biofuels Act(2006) which is equivalent to 1 m tons raw sugar or roughly the sugar requirement of some 38 M Filipinos at 26 kg per capita consumption 2 decades from now. Ethanol production is accompanied by a huge volume of liquid waste effluent called distillery slops ranging from 12-18 L/L of ethanol. Its disposal is both monetary-and energy costs intensive.