Routes for converting biomass to Energy 

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THEORETHICAL FRAMEWORK OF THE STUDY

Biofuels definitions

Biofuel is a gaseous, liquid and solid fuel which is mainly produced from biomass and used according to the current global energy demands to substitute the fossil fuels (Knothe, 2010).
There are different types of biomass and basically four types are defined as a source of biofuels such as: lignocelluloses which are derived from cellulose or plant dry matters, crops rich of sugar and starch, plants con-taining vegetable oils and fats and wet biofuels (i.e. sewage wastes and municipal wastes) (Walimwipi et al., 2012).
Based on the biomass and the type of technology that was used to ex-tract the biofuels, it can also be known as first generation or second gen-eration biofuels, first generation biofuels is produced from crops and wastes feedstock, while the second generation ones are shaped from the lingo-cellulosic biomass feedstock, according to the process and the conversion technology the first generation is related to a bio-chemical transformation pathway, whereas the second generations are created through thermo-chemical pathways (Walimwipi et al., 2012).
Biodiesel from Jatropha fatty acid or methyl ester of vegetable oil is a type of biofuel that is synthesized when the seeds oil react with methanol or ethanol in the presence of alkaline or basic catalyst.
Current researches are seeking higher productivity of biodiesel. There-fore, efforts are made to develop enzymes as catalysts to overcome the drawback of the alkaline or the basic catalysts, and according to Bacovsky et al. (2007) using enzymes as catalysts is more favorable due to the fact that enzyme catalysts can produce biodiesel under mild temperature, pressure and pH conditions, it also produces pure biodiesel and glycerol that does not require any further purification. The enzyme catalysts will improve the environmental standard related to the alkaline waste water and both the transesterfication of triglycerides and the esterification of the free fatty acid are performed in one step process (Bacovsky et al., 2007).

Routes for converting biomass to Energy

There are two main routes that have been used in large- scale to convert biomass into useful energy sources, the first rout is the thermo-chemical process and the second rout is bio-chemical process, and through both technologies three products of energy are obtained: heat, power and transport fuels (McKendry, 2002). Figure 2 summarizes the main routes of converting biomass into energy (EEA, 2013).

Jatropha Curcas

Jatropha Curcas L. is the Latin name which is always known as “Jatropha”, the genus contains 14 species and it belongs to the family Euphorbia-ceaa-Spurge and has various local names, in English it is known as physic nut, in French as pourghère, in Dutch as purgeernoot, Mmbono in Tan-zanian, Jatropha Curcas is a plant which yields seeds with higher oil con-tents, it can be grown under severe climate conditions such as tropical climate and land with little soil fertility, Jatropha has a toxic seeds which make it as a non-edible crop (Putten et al., 2010).
Jatropha seeds are non -edible and produced oil from 30 to 40%. There-fore, it is likely to be a noble source of energy to produce biodiesel (Kandpal & Madan, 1995). Moreover, the seeds cake can be exploited as organic fertilizer because it is rich of protein, nitrogen and pesticide and the plant remains useful for 35-50 years (Bio Zio, 2012).
Jatropha Curcas is a large grainy annual shrub which is grown up to 5 m high (Heller, 1996). Under normal condition from seedlings five roots are formed, one is central and the others are peripheral (Kobilke, 1989) as cited by Heller (1996). It has green to pale green colored leaves with a length and width of 6-15 cm and the leaves arrange themselves alternate-ly, the plant is always monoecious, consequently the male and female flowers are shaped on the same inflorescence and usually there are 20 male flowers in respect to each female flower and sometimes 10 male to each female flower where the inflorescence form in the leaf axil (Sachde-va et al., 2011). However, sometimes hermaphrodic flowers are present infrequently and self-pollinating occurred (Staubmann et al., 2010).
Ewurum et al. (2010) study as cited by Kamal et. al (2011) shows that the mature plant usually produces capsule shape fruits in winter or during the year if the soil moisture is good and temperature is appropriately high (Fig. 3). The seeds are black and range from 10 mm long and 10
mm wide and become matured when the seeds color changes from green to yellow, this usually takes 3 to 4 months after the flowering and there are 1375 seeds/kg in average (Li et al., 2010). List & Horhammer (1969-1979) as cited by Nahar & Hampton (2011) show that Jatropha leaves contain different chemical compounds such as saccharose, raffinose, stachyose, glucose, fructose, galactose, and protein. Fatty acid such as oleic, linoleic acids, palmatic and others acids are also reported (Perry & Metzger, 1980).

The potential of Jatropha Curcas as biodiesel feed stock

Several studies show positive energy balances for the Jatropha Curcas when it is used as feedstock for biodiesel production especially as fence plantations (Feto, 2011; Energy, 2009) due to the fact that it produces vi-able biodiesel and each hectare can provide about 1900 liters of biodiesel per year in addition to 3400 kilograms of waste biomass (Muok & Källbäck, 2008). According to several estimates made by experts, (Table 1) represents the yield of Jatropha seeds/hectare in different years (Bio Zio, 2012).
Jatropha Curcas can tolerate severe weather conditions and survives in dif-ferent sort of soils such as marginal, low fertility, degraded, fallow and wasteland. Jatropha Curcas can be also be grown along canals, roads, rail-way lines, fence boarder between farms, areas with low rainfall (200 mm/y) and alkaline soils with temperature above 20 C0. Jatropha Curcas is considered as a sustainable biofuels feedstock since it does not compete
with food productions, non- edible oils, control soil erosion, and help in poverty reduction (Kumar & Sharma, 2005).

Uses of Jatropha

Different parts of Jatropha Curcas have useful applications and uses. Jatropha have gained its importance due to the higher oil contents, in addition to its useful medical uses, some records show that Jatropha was used by Indians a long time ago for medical purposes in traditional ways, the main use of Jatropha is as fences around agricultural fields or to con-trol erosion on marginal soils (Peter et al., 2010). Moreover, it is used as fire wood, fuel for lamps & cooking stoves and direct engine fuel, the oil is also considered as alternative for soap production, on the other hand there are a lot of medical uses for Jatropha oil such as: the seed oil can be used to treat eczema, skin diseases and rheumatic, the seed cake are used as soil fertilizers, input for biogas production, input for combustion and production of charcoal (Peter et al., 2010). Jatropha liquid is used to inhibit watermelon mosaic virus (Tewari & Shukla, 1982) . Figure 4 summarizes the foremost uses of Jatropha Curcas (Nahar & Hampton, 2011).

Physical and chemical characteristics of Jatropha Curcas oil

Jatropha Curcas oil contains considerable amount of free fatty acids (FFAs) such as palmitic, stearic, arachidic, oleic and linoleic, these con-tents are higher in Jatropha oil relative to other non-edible biofuel plants such as Caster and Linseed (Martin et al., 2011).
Biodiesel from Jatropha is better than fossil fuel diesel in terms of ash contents, carbon residue, sulfur contents and acid value according to Singh et al. (2006). Table 2 illustrates the main characteristics of Jatropha oil, Jatropha methyl ester and petroleum diesel relative to international standards such as American Society for Testing and Materials (ASTM) and Detuches Institute für Normung (German Institute for Standardiza-tion) DIN.

Main process of converting Jatropha oil into biodiesels

In order to produce biodiesel from Jatropha there are different processes involved to turn the raw materials (fats and oils) into ester while separat-ing the glycerin.
The well-known process through which glycerin is separated from the biodiesel is known as transesterfication (Fig. 5). In this process, chemical ex-change takes place between (OR) of the ester compounds (R COOR) and alcohol such as Methanol (CH3OH) or Ethanol (CH3CH2OH) in the presence of a catalyst such as Sodium hydroxide (NaOH) or Potassi-um hydroxide (KOH) and finally the methyl or ethyl ester which is known as biodiesel is formed (Riemenschneider, 2005).
As seen in (Fig. 6) after crushing Jatropha seeds to produce fats and oils, a filtration (pre-treatment) process is used in order to get rid of impuri-ties and suspended particles which are not part of the oil such as: barks, FFAs, phosphorus, access water, and bits of the cakes (Nahar & Sunny, 2011) . After filtration, the transesterfication process is going to be start-ed by adding methanol or ethanol in the presence of catalyst to produce methyl ester (biodiesel). By-products such as: Glycerin, unchanged FFAs and water are sent to a separate tank to recover the glycerin from impuri-ties and the methanol that is not consumed during the transesterfication process goes to the recovery tank to be used again in the system.

Future of Jatropha as energy crop in Africa

Due to scarcity of fossil fuel reserves in most African countries, in addi-tion to the fact that Jatropha can withstand the harsh climate conditions and has no impacts on food security when it cultivated in the marginal lands, it is therefore seen by some experts as one of the suitable energy crops in the developing countries for large-scale biodiesel production. However, these assumptions and it’s characteristics are still not under-stood nor validated (Ouwens et al., 2007), all these statements regarding Jatropha can be true and false at the same time; true if clear policies about Jatropha biodiesel have been made, otherwise instead of seeing Jatropha as a future crop it will be as one of the coming disasters in nearest future in Africa, due to the fact that Jatropha without comprehensive studies and good planning might contribute to many negative impacts economically, socially and environmentally.
Nowadays, Jatropha oil plays a crucial role in small-scale decentralized systems to generate electricity in small villages and remote areas where there are no accesses to central power generation. In both Mali and Tan-zania biodiesel from Jatropha is being used to operate Multi Functional platforms (MFP) to provide different energy services and thus improved the livelihoods in these areas (United Nation, 2007).
Jatropha will be the future energy crops, if the current gaps and challeng-es facing the Jatropha have been identified and carefully considered such as funding’s, high investment costs, no clear policies, improvement of the marginal lands, R & D on plant agronomy to produce high seeds etc.

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Why National Policy on Biofuels in Africa

The main drivers of stimulation policies regarding bioenergy are: to in-crease the energy security; economic development and decrease CO2 emissions (Moller et al., 2011). Therefore, several governments and poli-cy makers started to establish new policies and regulations targeted at in-creasing biofuels to achieve EU policy objective of 20% reduction in GHGs by 2020. Furthermore, in 2007 the outcomes of the 4th assess-ment report of Intergovernmental Panel on Climate Change (IPCC) show the significant role of biofuels in the reduction of CO2 emission to achieve the future target of limiting the global warming (IPCC, 2007).
Other factors for stimulation biofuels policies in Africa are due to the scarcity, depletion of liquid fossil fuels and most of the fossil fuel coming from a small number of countries which are politically unstable (Gold-emberg, 2007). Similarly, the developing countries started to produce biofuels locally in order to cut down in the annual cost of the imported fossil fuel (Siwa & Martin, 2013) .About forty two countries in Africa are net energy importers while fewer countries are oil exporters because Af-rica has only 9.5% of world’s oil reserve which counts for 12% to the global oil production (Amigun et al., 2011).
Africa climate is seen as additional reason for stimulation of biofuel rules and Xlmlng et al., (2011) writes that, most of global biomass potential lies in the tropical areas where there is access to sunlight and irrigation. For all the above mentioned reasons, European countries started to es-tablish and regulate biofuels policies very early. However, fewer develop-ing countries have clear biofuel policies at the moment.

Feasibility of Jatropha oil for Biodiesel production

There are three key factors which can determine the profitability of the Jatropha seeds and its economic value. The first factor is the yield of the mature plant per hectare, the second one is the production cost and the last factor is the market price. From policy point of view, the Jatropha is economically viable when the oil barrel of Jatropha is 60-70 USD relative to fossil fuel (Soto et al., 2013a). Furthermore, the system of the produc-tion and the production cost are significant factors for Jatropha profita-bility since they will stimulate and improve the gross margin and return to the labors. On the other hand the biofuel productions will became more competitive when taking into account the externality and biofuels by products (Soto et al., 2013a). For most large-scale projects to become economically viable, several literatures review suggested that the optimi-zation of production cost, energy yield per hectare, adaptability to natural condition, storage potential, appropriate climate, labors availability, infra-structure and logistics are the most important factors that will enhance the feasibility of the Jatropha oil for biodiesel production.
The study carried out in Ethiopia by Feto (2011) shows that “of all pro-duction systems, cultivation of Jatropha in live – fence hedge is the most feasible from economic viewpoint” and also in Mali the low seeds prices and higher labors cost influenced the profitability of Jatropha biodiesel. Therefore, by -products might be exploited in order to improve the prof-itability of the Jatropha system (Soto et al, 2013b).
In Kenya according to a study based on farmer’s interview which was performed in 2009 to assess the agronomic and economic viability of Jatropha, most Jatropha farms in the country revealed very low yields and the cost of production was very high which make it economically unfeasible for smallholder projects when Jatropha grown within a mono-culture or intercrop plantation model. However, the most economic ap-proach for small-holders according to field experiences is when the Jatropha is naturally growing as a fence plantation and this approach is conforming to Ethiopian model (Energy, 2009).
For the above mentioned reasons, the Jatropha value chain is a key indi-cator for the probability and feasibility of Jatropha production. Figure 7 illustrates the Jatropha value chain from plantation stage to the supply of the final products to the end users in forms of biodiesel or utilization of the seeds cakes as fertilizers (Faso Gaz, 2013).
Soto, et al. (2013a) show that the Jatropha value-chain can leads to con-siderable reductions in the greenhouse gas emissions when all the ad-verse impacts during the biodiesel life cycle are analyzed using sensitivity analysis in order to assess any related risks by identifying the variables that have great influence in the projects net profits using different tech-niques such as Benefit Cost Ratio (BCR), Internal Rate of Return (IRR), Net Present Value (NPV) or other indicators.

Sustainability criteria for biofuels (Jatropha)

According to 2005 World Summit on Social Development, the objec-tives of sustainable development are: to identify the economic, social and environmental issues related to any developments (Shah, 2005).
Sustainability criteria should consider all the predicted impacts at the stage of initiating the Environmental Impact Assessment (EIA) and the Strategic Environmental Assessment (SEA), because the whole picture of sustainability can be seen in the context of these two processes.
EIA can be defined as a process for identifying and evaluation of the likely consequences (impacts) of any particular activities. Therefore, EIA play a fundamental role as one of the instruments to achieve sustainable development and the economic development and social development must be placed in their environmental contexts (Glasson et al., 2013).
SEA is defined as a strategic tool towards sustainability by linking differ-ent issues such as social, institutional and economic in strategic manner to help in driving the development into sustainability pathways (Par-tidário, 2012).
Energy security is a central issue for socio-development and could pro-vide all the services towards better life (Singh & Sooch, 2004) . For bio-energy, a number of studies have been performed to classify the most significant factors that might contribute to the sustainability of bioenergy and they have all demonstrated that any bioenergy project should give a positive energy balance as well as environmental benefits (Mangoyana, 2007).
The most environmental impacts are related to: Reduction of GHGs, soil conservation & erosion, land use changes, loss of biodiversity, over-exploitation of water resources and contamination due to application of fertilizers (environmental impacts are discussed in section 4 of this re-port).
Social impacts are associated with:
Poverty alleviation: Biofuels can help in poverty alleviation due to creation of jobs and increasing the income per capita (Prasad & Visagie, 2005).
Food versus fuel: when agricultural lands are planted by energy crops.
Land tenure and cultural heritage: Most of the lands granted for biofuels pro-jects are belong to villagers whom are economically and socially vulnera-ble and their land tenure is not formal (Amigun et al., 2011). Lands for these communities is not only a source of economy and income, it is also a matter of pride and spirituality and people always struggle to maintain this precious wealth that have been given to them by their ancestors and they should maintain and keep it for both themselves and future genera-tions (Young, 2000).
Health impacts: The production of biofuels is believed to have both posi-tive and negative health impacts; sustainable biofuel will improve the air quality due to the reduction of CO2 pollution. On the other side, some biofuels projects might lead to some health impacts such as water con-tamination due to the release of some toxic materials (Jatropha seeds are highly toxic) when are discharged from the effluent of biofuels pro-cessing plants (TERI, 2008).
The economic issues are related to biofuels value chain such as: invest-ment costs, Jatropha productivity, energy yields, reduction in fuel usage, market prices and etc. (as discussed in section 3.10).

Table of contents :

Abstract
1. THE SCOPE OF THE STUDY 
1.1. General overview of the study area
1.2. Aims and Objectives
1.3. Scope and Limitations
2. METHODLOGY 
2.1. Literature review and desk top analysis
2.2. Consultations of experts in the field of biofuels
2.3. Evaluation of the finding against some environmental criteria
3. THEORETICAL FRAMEWORK OF THE STUDY 
3.1. Biofuels definitions
3.2. Routes for converting biomass to Energy
3.3. Jatropha Curcas
3.4. The potential of Jatropha Curcas as biodiesel feed stock
3.5. Uses of Jatropha
3.6. Physical and chemical characteristics of Jatropha Curcas oil
3.7. Main process of converting Jatropha oil into biodiesels
3.8. Future of Jatropha as energy crop in Africa
3.9. Why National Policy on Biofuels in Africa
3.10. Feasibility of Jatropha oil for Biodiesel production
3.11. Sustainability criteria for biofuels (Jatropha)
3.12. The current status of some projects of Jatropha in Africa
4. RESULTS AND DISCUSSIONS 
4.1. Case study of Sudan
Biofuels development in Sudan 13 4.1.1.
Current situation of Jatropha in Sudan 14 4.1.2.
Potentials of Jatropha in Sudan 15 4.1.3.
Related Risks of Jatropha in Sudan 15 4.1.4.
4.2. Case study of Ethiopia
Reasons and policy for the increase of biofuel in Ethiopia 15 4.2.1.
Some Scenarios of biofuel projects in Ethiopia 16 4.2.2.
Potentials of Jatropha in Ethiopia 17 4.2.3.
Some Drawbacks of Jatropha in Ethiopia 17 4.2.4.
4.3. Case study of Kenya
Jatropha Development in Kenya 20 4.3.1.
Status of production of Jatropha in Kenya 20 4.3.2.
Policies supporting biofuel development in Kenya 21 4.3.3.
Potentials of Jatropha in Kenya 22 4.3.4.
Drawbacks of Jatropha in Kenya 23 4.3.5.
4.4. Case study of Tanzania
Jatropha Development in Tanzania 25 4.4.1.
Mohammed Abaid TRITA-LWR Degree Project 15:02
Potentials Impacts of Jatropha in Tanzania 27 4.4.2.
Socio economic issues 27 4.4.3.
Drawbacks of Jatropha in Tanzania 28 4.4.4.
5. SUMMARY, CONCLUSION AND RECOMMENDATIONS 
5.1. Summary of the findings
5.2. Conclusion
5.3. Recommendations
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