Costs of ethanol production from sugarcane in Eastern Batangas

Issue Date

8-2007

Abstract

Three major energy- and monetary-using stages in ethanol production from sugarcane were analyzed: cane production, cane processing and distrilley 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 3 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 distrilley 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 82 L/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 canes 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 M L of ethanol needed by 2011 under the Biofuels Act (2006) which is equivalent to 1 M tons raw sugar or roughly the sugar requirements 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 distrillery slops ranging from 12-18 L/L of ethanol. Its disposal is both monetary-and energy costs intensive.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

32

Issue

2

Page

25-47

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables

Language

English

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