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CHAPTER 2.0 – LITERATURE REVIEW
2.01 BIOFUELS
There is extensive research on the topic of biofuel as such the review of literature will seek to only
highlight a few studies that are seen as pivotal to this study.
Biofuel is a promising source of energy because it is generated by the process of photosynthesis,
where energy from the sun is captured and transformed into biomass that can be combusted to
produce energy1.
The sharp increase in the price of petroleum products, the finite nature of fossil fuels, growing
environmental concerns, especially related to greenhouse gas emissions, and health and safety
considerations are forcing the search for new energy sources and alternative ways to power the
world's motor vehicles, according to the paper “The Emerging Biofuel Market: Regulatory, Trade
and Development Implications”2. This paper states that increasing the production, use and trade of
bio-fuels may slow down the process of global warming and provides opportunities for developing
countries to diversify agriculture production, raise rural incomes, and raise quality of life. In
addition, biofuels have the possibility of enhancing food security, and reducing expenditure on
imported fossil fuels. In its essence this paper looks at the role that bio-fuel can play in
complementing fossil fuels, due to its inherent advantages in combating the negatives of fossil
fuels but also capturing the possibility that exists in biofuels to be as or even more degrading to
social, environmental and economic spheres, thus the paper emphasizes the importance of policies
in structuring sustainable bio-fuel production. While emphasizing that bio-fuels cannot stand alone
or be viewed as the only initiative to combat the problems of energy provision, climate change and
development, but that other innovations and policies must be implemented to complement the use
of bio-fuels.
1
http://www.tamu.edu/faculty/tpd8/BICH407/Brazilenvsoc2.pdf
2
http://www.unctad.org/en/docs/ditcted20064_en.pdf
Though biofuels are widely regarded as means to provide energy needed for development without
the degrading effects of fossil fuels; the increasing production of bio-fuels are not without its
challenges.
Notwithstanding that the impacts of increased bio-fuel production on greenhouse gas emissions,
land, water and biodiversity vary widely across countries, biofuels, feedstocks and production
practices, there is a strong and immediate need for harmonized approaches to life-cycle analysis,
greenhouse gas balances and sustainability criteria, according to the document “Liquid Biofuels
for Transport Prospects, risks and opportunities”3. This document emphasizes that biofuels are
only one component of a range of alternatives for mitigating greenhouse gas emissions and that
policy objectives such as different forms of renewable energy, increased energy efficiency,
conservation, and reduced emissions from land degradation and deforestation may prove cost
effective. In addition, greenhouse gas balances are not positive for all biofuels and that for the
purpose of solely combating climate change; investment should be directed towards crops that
have the highest possible greenhouse gas balances with the lowest environmental and social costs,
where biofuels production remains small in the context of total energy demand. In assessing the
constraints associated with the use of biofuel the paper highlights the issue of environmental
impacts that can be generated from all stages of biofuel-feedstock production and processing.
Processes related to land use change tend to dominate and during the next decade the speed at
which policy-driven growth in demand for biofuels is likely to accelerate the conversion of non agricultural lands to crop production. This will occur directly from biofuel feedstock production
and indirectly from other crops displaced from existing cropland. This paper discusses the reality
of biofuels being a more socially beneficial, environmentally friendly, and a way to meet energy
demand as it relates to its potential positive effect as compared to fossil fuels. And deliberates if
biofuels are not sustainably produce and policies are not in place to prevent unsustainable
production of fossil fuels viewing biofuel as only one of many innovations, not the only innovation
to combat the problems created by fossil fuel use, then the inherent benefits of biofuels will not be
realized and biofuels may become a bigger problem than the use of fossil fuels.
3
http://www.greenfacts.org/en/biofuels/l-3/4-environmental-impacts.htm
The success of biofuels development depends first and foremost on the proper selection of the raw
material to be used in the production of a bio-fuel (ECLAC, 2007)4. This document stated in this
regard, the choice of biofuel crops depend fundamentally on the following factors:

Agro-industrial productivity, which combines agricultural productivity and industrial
productivity and is evaluated in litres of fuel per hectare;

Technological availability, or the existence of known and accessible processes for
converting the raw materials into biofuels;

The energy balance, which expresses the ratio of energy demand to production for a given
raw material conversion process;

The availability of energy by-products that are capable of meeting the energy requirements
of the conversion process;

Environmental impact at the level of agricultural and industrial production;

Competition with food production;

The level of knowledge and dissemination of crops in the context under consideration.
Using these criteria, a preliminary selection can be made from among different crops that can be
used for the production of ethanol, with starchy crops (products that clearly have food value and a
low energy yield) and corn (marginally attractive energy balance) can be ruled out or atleast given
lower priority (ECLAC, 2007)5. According to the document sugarcane stands out as a favourable
alternative in Guyana given the fact that it has been cultivated for centuries and has an energy
production /demand ratio of 8, one of the highest available. More over with the use of bagasse, the
industrial process can be self sufficient and even generate a surplus.
This paper highlights the potential Guyana has in the area of biofuels and concluded that in the
area of bioethanol production, the use of exhausted molasses from sugarcane was the most feasible
feedstock and possesses the greatest potential for Guyana from using the criteria above.
4
5
http://www.eclac.org/publicaciones/xml/2/27952/lcw118i.pdf
http://www.eclac.org/publicaciones/xml/2/27952/lcw118i.pdf
2.02 BIOETHANOL
Similarly, there is extensive information on the subject of bioethanol, as such this review of
literature serves to introduce bioethanol by highlighting some of its characteristics.
As regards the role of biofuels and particularly ethanol in the supply of fuels, the introduction of
ethanol in gasoline blends deserves some comment; this technological option had been proposed
as far back as the late nineteenth century by Henry Ford, who used pure ethanol in his early
models6.Ethanol is a first generation fuel; Conventional “first generation” ethanol is made by
fermenting sugars from plants with high starch or sugar content into alcohol, using the same basic
methods that brewers have relied on for centuries7.
Bioethanol, or rather ethanol, itself belongs to the chemical family – alcohols - and has a structure
of C2H5OH and a strong odour8.Ethanol is a high octane fuel and has replaced lead as an octane
enhancer in petrol, by blending ethanol with gasoline we can also oxygenate the fuel mixture so it
burns more completely and reduces polluting emissions9. Bioethanol can be used directly in cars
designed to run on pure ethanol (hydrated ethanol, which has usually about 5 per cent water
content), or blended with gasoline to make "gasohol"10. Dehydrated (anhydrous) ethanol is
required for blending with gasoline11. Ethanol or ethyl alcohol (C2H5OH) is a clear colourless
liquid, it is biodegradable, low in toxicity and causes little environmental pollution if spilt and it
burns to produce carbon dioxide and water12.
6
ibid
http://www.worldwatch.org/files/pdf/biofuels.pdf
8
http//www.erec.org/fileadmin/erec_docs/Project_Documents/RESTMAC/Brochure5_Bioethanol_low_res.pdf
9
ibid
10
http://www.unctad.org/en/docs/ditcted20064_en.pdf
7
11
12
http://www.unctad.org/en/docs/ditcted20064_en.pdf
http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/biofuels/what_bioethanol.htm
The principle fuel used as a petrol substitute for road transport vehicles is bioethanol; bioethanol
fuel is mainly produced by the sugar fermentation process, although it can also be manufactured
by the chemical process of reacting ethylene with steam13.
During the fermentation reactions, sucrose is hydrolyzed into fructose and glucose, which are
converted into ethanol and carbon dioxide as represented by the equation14:
C6H12O6 → 2C2H6O + 2CO2
Ethanol is an oxygenated fuel containing 35% oxygen, which reduces particulate and NOx
emissions from combustion15. The use of bioethanol can reduce emissions of carbon monoxide
and hydrocarbons, in which this emission reduction is particularly evident in older vehicles with
less sophisticated fuel management systems16. The environmental advantage of ethanol over
gasoline is the reductions in emissions that have an adverse effect on the environment and it can
be sustainability produced.
2.03 SUGARCANE BIOETHANOL TECHNOLOGY
Sugar-based bioethanol is a simple process as sugars is already present in biomass (Sugarcanebased bioethanol: energy for sustainable development)17. Generally, the process is based on
extraction of sugars (by means of milling or diffusion), which may be then taken straight to
fermentation and subsequently the wine is distilled, according to the document: “Sugarcane-based
bioethanol: energy for sustainable development,” (see Figure 5 on the next page).
13
http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/biofuels/what_bioethanol.htm
http://www.nipeunicamp.org.br/site/adm/modulos/publicador/documentos/arquivos/File/Publica%C3%A7%C3
%B5es/Production%20of%20bioethanol%20and%20other%20bio-based%20materials.pdf
14
15
16
ibid
http://www.eeca.govt.nz/sites/all/files/biofuels-factsheet-jun-08_1.pdf
17
http://sugarcanebioethanol.org/en/download/bioethanol.pdf
The aforementioned document states, the initial processing stages for bioethanol are basically the
same for sugarcane. Once in the mill sugarcane is washed and sent to the preparation and extraction
phases. Extraction is made by roll mills – that separate the sugarcane juice containing saccharose
from the bagasse, which is sent to the mill’s power plant to be used as fuel. The juice containing
sugars can then be used for sugar production or ethanol production.
Figure 12: Technological route for bioethanol production from Sugarcane
(Sugar Biomass) Sugar Cane
Extraction through Pressure of Diffusion
Fermentable Sugar Solution
Fermentation
Distillation
Ethanol
Source: Sugarcane-based bioethanol : energy for sustainable development / coordination BNDES
and CGEE – Rio de Janeiro : BNDES, 2008, p. 66
According to the document, in sugar production the juice is initially screened and chemically
treated for coagulation, flocculation and precipitation impurities, which are eliminated through
decanting. The filter cake, used as fertilizer, is generated by recovering sugar out of the decanted
slurry by means of rotary vacuum filters. The treated juice is then concentrated in multiple effect
evaporators and crystallized. In such process only part of the saccharose available in the sugarcane
is crystallized and the residual solution with the higher sugar content can be used in the process
once again to recover more sugar. The molasses produced can be used as an input for bioethanol
production through fermentation, because it contains some saccharose and a high amount of
reducing sugars (such as glucose and fructose, resulting from saccharose decomposition.
The document states, sugarcane bio-ethanol production may be based on fermentation, whether
using the sugarcane juice or using a mix of juice and molasses. In sugarcane-juice bioethanol the
first stages of the manufacturing process, from sugarcane receipt to initial juice treatment, are
similar to the sugar manufacturing process. In a more well-rounded treatment the juice is limed,
heated and decanted as in the sugar process. After treatment the juice is evaporated to balance it
sugars concentration and it may be mixed with molasses, generating sugarcane mash, a sugary
solution which is ready to be fermented.
The mash is sent to fermentation reactors, where yeast are added to it and fermented for a period
from 8 to 12 hours, generating wine (fermented mash, with ethanol concentration from 7 – 10 %).
Subsequently wine yeast are recovered by centrifugation and treated for new use while the wine
that remains is sent to the distillation columns.
In distillation bioethanol is initially recovered in hydrated form, producing vinasse or stillage as
residue, generally at a ratio of 10 to 13 litres per litre of hydrated bio-ethanol produced. In this
process other liquid fractions are also separated, producing second generation alcohols and fusel
oil. Hydrated ethanol can be stored as final product or may be sent to the dehydration column.
Nevertheless, as it is an azeotropic mixture, its components cannot be separated by distillation
only. In the dehydration column, cyclohexane is added on top and the anhydrous ethanol is
removed from the bottom (see Figure 6 on the next page).
Figure 13: Sugar and Sugar-cane based bioethanol production chart
Sugar cane
Bagasse
Boilers
Milling
Juice
Chemical Treatment
Filtration
Filter Cake
Molasses
Evaporation
Fermentation
Cooking
Distillation
Centrifugation
Rectification
Vinasse
Ethanol
Drying
(Hydrated)
Sugar
Dehydration
Ethanol
(Anhydrous)
Source: Seabra 2008 (Sugarcane-based bioethanol : energy for sustainable development /
coordination BNDES and CGEE – Rio de Janeiro : BNDES, 2008, p.75)
2.04 SUGARCANE BIOETHANOL INDUSTRY
According to Joachim von Braun (2007) about 80 developing countries, for instance, grow and
process sugarcane, a high-yielding crop in terms of photosynthesis efficiency that can also be used
to produce ethanol. With international sugar prices moving generally downward until recently,
partly owing to protectionist sugar policies in some OECD countries, sugarcane production for
ethanol has become a more attractive option for developing-country farmers (Joachim von Braun,
2007).
This fuel was first used on a large scale in Brazil, where a law was adopted in 1931 for the
compulsory of 5 % ethanol in imported gasoline, thereby initiating a learning process that was the
basis for the significant expansion observed in recent decades (ECLAC, 2007). According to the
ECLAC, since the 1980s Brazil has been using 25 % ethanol in gasoline sold, with demand
currently standing at approximately 16 billion litres of ethanol and projected to increase to over 22
billion litres in 2013, based on current high growth rates. This estimate is corroborated by the fact
that 40 new sugar factories are being constructed in Brazil18.
The great majority of ethanol produced in the world is from sugarcane, mainly in Brazil, and corn
in the United States (which together account for 35.4 million cubic meters, about 72% of the
world’s production), according to the document, “The Sustainability of Ethanol production from
Sugarcane, (Jose´ Goldemberg , et al.)19. This document states that all the energy needs for its
production (heat and electricity) come from bagasse and excess bagasse is used to generate
additional electricity to be fed into the grid, the direct consumption of fossil fuels is limited to
transportation trucks, harvesting machines and the use of fertilizers. And compared to ethanol
produced from other feedstocks, sugarcane ethanol has a very favourable greenhouse gas emission
18
19
http://www.eclac.org/publicaciones/xml/2/27952/lcw118i.pdf
http://cenbio.iee.usp.br/download/publicacoes/JEPO2750.pdf
balance. And this is due to this positive energy balance, the sugar ethanol sector avoids emissions
equivalent to 13% of all Brazilian industrial, commercial and residential sectors as compared with
corn and other feedstocks that require considerable imports of fossil fuels in the producing plants.
This results in an energy balances that vary from almost zero to only slightly higher than one. The
document explains that expansion in the ethanol industry of Brazil to reach more markets will
stretch the boundary of sustainability of the industry.
Ethanol from sugarcane is one of the most promising biofuels because its energetic balance is
generally positive, meaning that the growing sugarcane absorbs more carbon than is emitted when
the ethanol is burned as fuel, according to the document, “Expansion of Sugarcane Ethanol
Production in Brazil: Environmental and Social Challenges”
20
. The aforementioned document
emphasized that the expansion of the industry to increase export capabilities could result in social
and environmental challenges that can result in the degradation of both of these dimensions.
Brazilian sugar cane is the most energy efficient crop for biofuels today, due to a highly efficient
production process, suitable growing conditions, manual labour and active government policy and
subsidies since the 1970’s, according to the document, “Biofuels – Potential and Challenges for
Developing Countries (2009)”21. This document examines the Brazilian Ethanol industry as a case
study noting the opportunities and challenges that exists. It states that out growers schemes have
succeeded in ensuring that 30-35% of sugarcane in Brazil is produced by small scale farmers and
that ethanol production has created around one million employment opportunities that depend on
the degree of mechanization. In addition, the country has reduced dependency on oil imports and
exposure to volatile international prices.
There is an increasing demand of ethanol in Sweden, an interest to mix ethanol into gasoline in
Japan, a potentially large interest from other European countries and there is a growing American
interest for mixing sugar cane ethanol into gasoline; would the latter take place an American
20
http://www.tamu.edu/faculty/tpd8/BICH407/Brazilenvsoc2.pdf
21
http://www.swedbio.com/dokument/factsheet-biofuel-en.pdf
demand of 5 million m3 per year has been indicated ( Grona Bilister, 2006, “Ethanol production
from sugarcane in Brazil”)22.
Therefore, Guyana is in an ideal position to take full opportunity of a bioethanol industry not just
for domestic consumption but also for international trade, with the country possessing similar
equatorial and environmental conditions to that of Brazil.
2.05 SUGARCANE BIOETHANOL IN THE CARIBBEAN
In 1984, ethanol was included into a list of commodities for which duty–free access to the United
States was allowed under the Caribbean Basin Initiative (CBI)23. The Caribbean Basin Initiative
is a carefully designed development program to help Caribbean countries attract investors and
diversify exports24. CBI grants eligible countries with duty-free access to the U.S. market for most
products, including a duty-free quota of up to 7% of the US domestic market for non-indigenous
ethanol25.
Some of the countries in the Caribbean have established ethanol plants to take advantage of the
CBI initiative to export ethanol to the United States and such has developed ethanol industries.
This has made ethanol a very important commodity that is exported from the Caribbean Region to
the United States Market.
There are nine ethanol facilities in five Caribbean countries: Jamaica, EL Savador, Costa Rica,
Trinidad and Tobago, and St. Croix26. These ethanol facilities process sugar cane based hydrous
ethanol from other countries into anhydrous/fuel grade ethanol.
22
http://www.gronabilister.se/file.php?REF=39461a19e9eddfb385ea76b26521ea48&art=376&FILE_ID=200605110
84611.pdf
23
http://www.pcj.com/e10/pdf
24
http://www.caribbeanethanolproducers.com
25
ibid
26
ibid
The plants have the capacity to produce 700 million gallons annually for the U.S. market. These
plants represent over $ 300 million in investment, a significant portion of which has come from
U.S. investors27.
The ethanol industry has generated hundreds of indirect and direct jobs, hundreds of millions of
dollars in foreign exchange, and constitutes an “anchor” investment that encourages up – stream
economic development in the Caribbean28.
More than 80% of the CBI exports from Jamaica is ethanol29. Jamaica is the largest producer of
fuel grade ethanol in the Caribbean Community (CARICOM); in addition to exporting ethanol
Jamaica has mandated the blending of 10 percent ethanol with gasoline (E10 blend) on 1st March
201030. The country’s three ethanol refineries produce (using raw ethanol imported from Brazil
and elsewhere) about 150 million gallons of fuel grade ethanol for export to the US31.
Similarly, Costa Rica has mandated the blending of ethanol with gasoline. The government of
Costa Rica has mandated that all gasoline sold in Costa Rica is to be blended with 7% ethanol
from October 200832.
27
28
29
ibid
http://www.caribbeanethanolproducers.com
ibid
http://www.greenislandinc.com/news-commentary/2008/07/
31
ibid
32
http://www.insidecostarica.com/dailynews/2011/april/20costarica11042007.htm.
30