Biofuels utilisation to mitigate Climate Change
Ashwini Kumar
Alexander vonHumboldt Fellow
Energy PlantationDemonstration Project Centre.
Department of Botany, University ofRajasthan,
Jaipur – 302 004, INDIA
Phone: 0091-0141-2654100 (M) 0091-9461663610
http://www.science20.com/profile/professor_ashwani_kumar
E-mail :Ashwanikumar214@gmail.com
ABSTRACT: Global climate change has stimulated efforts to reduce CO2 emissions. Photosynthetic organisms use solar energy to generate reducingequivalents and incorporate atmospheric CO2 into organic molecules.Cellular phenotype is a manifestation of gene expression levels, metabolicdemand, resource availability, and cellular stresses. The variation in rawmaterial for production of biofuels ranges from hydrocarbon yielding plants,non-edible and edible oil yielding plant, corn, sugarcane to lingo-cellulosicwaste to algal biofuels. Currently,cellulosic biofuels and algal biodiesels are prominent biological approaches to sequester and convert CO2.Today, ethanol and biodiesel arepredominantly produced from corn kernels, sugarcane or soybean oil. Howeveranother biofuel feedstock, lignocelluloses—the most abundant biologicalmaterial on earth is being explored. Lignocelluloses is everywhere—wheatstraw, corn husks, prairie grass, discarded rice hulls or trees. The race is onto optimize the technology that can produce biofuels from lignocellulosessources more efficiently—and biotech companies are in the running. There iscampaign, which advocates that 25% of US energy come from arable land by 2025.The EU had called for a threefold increase in biofuel use by 2010, to 5.75% oftransportation fuel.
Key words: Biomass,Biofuel, Climate change, Hydrocarbons,Latex, Non-edible oil yielding plants, Jatrophacurcas, Euphorbia , Ethanol and Bio-diesel.
1. INTRODUCTION:
Useof biomass for energy and industry allows a significant quantity ofhydrocarbons to be consumed without increasing the CO2 content ofthe atmosphere and thus makes a positive contribution to the Greehouse effectand to the problems of "global change" as occurs in bothindustrialized and developing countries (Kumar, 2008, Kumar 2011) Climate change is anylong-term significant change in average temperature, precipitation and windpatterns. It takes place due to emissions of greenhouse gases. Carbon dioxide (CO2) is the mostimportant greenhouse gas and increasing the use of biomass for energy is animportant option for reducing CO2 emissions. Carbon dioxide emissionis projected to grow from 5.8 billion tonnes carbon equivalent in 1990 to 7.8billion tonnes in 2010 and 9.8 billion tonnes by 2020 (Fig.1) (Kumar, 2001) .
Fig 1. Increasing levels of carbon di oxide in millionmetric tonnes (MMT).
TheKyoto conference agreement indicates the role clean energy sources will play infuture. Biomass is renewable, non pollutant and available world wide asagricultural residues, short rotation forests and crops. Thermochemicalconversion using low temperature processes are among the suitable technologiesto promote a sustainable and environmentally friendly development. Biomass canplay a dual role in greenhouse gas mitigation related to the objectives of theUnited Nations Framework Convention on Climate Change (UNFCC) i.e. as an energy source to substitute forfossil fuels and as a carbon store. The fact that nearly90 percent of the worlds population will reside in developing countries by 2050probably implies that local solutions for energy needs will have to be found tocope up with the local energy needs on one hand and environment protection onthe other hand (Table 1).Biomass should be used instead of fossilenergy carriers in order to reduce (i) CO2 emissions (ii) the anticipatedresource scarcity of fossil fuels and (iii) need to import fuels from abroad(Kumar, 2001).
Table 1 : Future Trends of Population Growth (in Billion People)
|
|
1990 |
2020 |
|
World |
5.2 |
7.9 |
|
EU |
0.36 |
0.38 |
|
DCs |
4 |
6.4 |
1.1 Globalland availability and biomass production:
Global land availability estimatesfor energy crop production vary widely between 350 and 950 million hectares (Alexandratos, 1995). Biomass resources are potentially the worlds largest andsustainable energy source a renewable resource comprising 220 billion oven dry tones (about 4500 EJ) of annual primaryproduction. The annual bio-energy potential is about 2900 EJ though only270 EJ could be considered available on asustainable basis and at competitive prices. Current commercial andnon-commercial biomass use for energy is estimated at between 20 and 60 EJ/arepresenting about 6 to 17 % of the world primary energy. Most of the biomass is used in developingcountries where it is likely to account for roughly one third of primaryenergy. As a comparison, the share of primary energy provided by biomass inindustrialized countries is small and is estimated at about 3 % or less (Fig 2).Agriculture and allied sectors contribute nearly 22 percent of Gross DomesticProduct (GDP of India), while about 65-70 percent of the population isdependent on agriculture for their livelihood. The agricultural output,however, depends on monsoon as nearly 60 percent of area sown is dependent onrainfall. Most of the population dependent on agriculture in India uses biomass for fuel in open chulhas ( firestoves) with poor fuel efficiency andlot of smoke generation causing serious asthmatic problems in rural women andchildren.
Fig. 2
1.2 Advantages of using biofuels:
Thereare several advantages of using biofuels: biodiesel burns up to 75% cleaner thanpetroleum diesel fuel. Biodiesel reduces unburned hydrocarbons (93% less),carbon monoxide (50% less) and particulate matter (30% less) in exhaust fumes,as well as cancer-causing PAH (80% less) and nitrited PAH compounds (90% less)(US Environmental Protection Agency), and Sulphur dioxide emissions areeliminated (biodiesel contains no sulphur). Biodiesel is plant-based and using it adds no extra CO2greenhouse gas to the atmosphere. Nitrogen oxide (NOx) emissions may increaseor decrease with biodiesel but can be reduced to well below petro-diesel fuellevels. Biodiesel exhaust is not offensive and doesn't cause eye irritation.
Biodiesel can be used in any dieselengine without modification. Biodiesel can be mixed with petro-diesel in anyproportion, with no need for a mixing additive. Biodiesel has a higher cetane numberthan petroleum diesel because of its oxygen content. The higher the cetane number, the more efficient the fuel -- the engine startsmore easily, runs better and burns cleaner. With slight variations depending on the vehicle, performance and fueleconomy with biodiesel is the same as with petro-diesel. Biodiesel is a muchbetter lubricant than petro-diesel and extends engine life -- even a smallamount of biodiesel means cleaner emissions and better engine lubrication: 1%biodiesel added to petro-diesel will increase lubricity by 65%. Theozone-forming (smog) potential of biodiesel emissions is nearly 50% less thanpetro-diesel emissions.
1.3 EU mandate:
Worldwide production of biodieselincreased by 60% in 2005, and ethanol by 19% over the previous year’sproduction, as per World watch Institute, USA. The EU mandated that three timesmore than the current level of 2% of the total energy content of petrol anddiesel needs to come from renewable fuels. Countries like Thailand are aimingfor a 10% renewable mix in the next five years; India 20% by 2020. Sweden has statedthat it aims to become 100% energy independent by 2020; most of thisindependence will come through its own nuclear power, but renewable fuels willlikely make up the balance.
1.4 Hypothesis
1. Photosyntheticorganisms use solar energy to generate reducing equivalents and incorporateatmospheric CO2 into organic molecules.
2. Differentplant species can provide biomass and biofuel in a three tier system developedby us (Kumar, 2001) :
a. Treespecies of fast growing nature can be used as uppermost tier of biomass.
b. Hydrocarbonyielding plant can make lowest tier and hydrocarbons from plants can beconverted to bio-diesel.
c. Nonedible oil yielding plants provide can be used to obtain biodiesel and theymake middle level of biomass production.
3. Conversionof lignocellulose plant material and waste for production of biomass.
a. Carboncaptured in cellulosic biofuels
b. Algalbiodiesels are prominent biological approaches to sequester and convert CO2.
c. Lipidproductivity of many algae greatly exceeds that of the best cellulosic ethanolproduction and can be used for biomass production.
5. Geneticengineering approach
6. Directconversion of CO2 to fuels or chemicals.
1.5 Some of the Biofuels include:
Bioethanol, Biobutanol, Biodiesel, Vegetableoils, Biomethanol, Pyrolysis oils,
Biogas, Biohydrogen.
Biodiesel:Technically, Mono-alkyl esters of long chainfatty acids derived from renewable lipid feedstock such as vegetable oilsand animal fats for use in Compression Ignition engines”. The definition eliminates pure vegetable oils.
Depending on the feed stock it may be referred as :
– Soybean methyl ester - SMEor SOME
– Rape methyl ester - RME
– Fatty acid methyl ester -FAME (a collective term including both of the above).
– Vegetable oil methyl ester -VOME yielding plants provide bio-diesel.
1.6 Presentstatus and future prospects:
a) Wood, wood chips agriculturewaste to Briquetting, Gasifier, Vacuum pyrolysis or Bio-gas, heat andelectricity generation.
b) Oil to trans-esterificationto obtain Fatty acid methyl ester (FAME) e.g. Rape seed methyl ester ( RME).
c) Liquid hydrocarbons tohydro-cracking – cracking of tri-terpenoid chain and adding of hydrogen usingzeolite catalyst in bio-refinery.
1.7 Nextgeneration biofuels:
· Lignocellulosic biofuelsmade from the lignin and cellulose in the cell walls of plants.
· The feedstocks for thesebiofuels – trees, grasses, or leftover plant materials – have several potentialadvantages.
· Require less intensiveagriculture and may be grown on “marginal” land, reducing competition forresources.
· Could be made fromagricultural or forestry residues such as rice husks and corn stover.
· 2007 UN report estimated
– Biofuels commercialized by2015
– Competitive withpetroleum-based fuels by 2025-2030.
Second and third generation biofuels: altering host material and /or developingnew enzyme systems.
a. Metabolic engineering for entireproduct
b. Industrialapplication of biofuel inclusive of related bio products of commercial valuefrom fourth generation products.
Direct conversion in tobiofuel.
1.8 Objectives of study:
a) Firstgeneration biofuels: Developing first generation biofuel crops to be grown insemi arid regions on wasteland.
b) Lactiferouscrops: Euphorbiaceae, Asclepiadaceae, Compositae, family members containinglatex as biofuel crops. Strategy to develop their agro-technology. Biomass conversion studies in collaborationwith IIP, Dehradun.
c) Collection and evaluation of highyielding Jatropha curcas fromdifferent locations in Rajasthan – Germplasm collection, evaluation in collaboration at TERI, New Delhi, raising stock material in nursery from elitesamples.
d) Agronomical and multilocationaltrial of selected genotypes.
e) To standardize nursery techniquesfor large scale planting material in vivo and in vitro.
f) To demonstrate the agro-forestrypractices for cultivation of Jatrophacurcas in wastelands and tostandardization of the growth parametersfor improvements.
g) To generate information oneconomics of production costs for different regions.
h) To evaluate quality and quantityof liquid fuels under actual field conditions of large scale cultivation.
i) To standardize growth cycle andproductivity in terms of total production vs biofuel production.
j) Improving the plant productivityusing various physical, physiological, biochemical parameters includingnutritional and hormonal applications.
k) To generate scientific andtechnological information for large scale applications.
l) To establish pilot plant forextraction of biodiesel.
m) Village level plantation in 40villages in Alwar district
n) Education on use of biofuels andestablishment of mini bio-diesel plants on site in Alwar district.
2. METHODOLOGY:
a) Growth of cultivation of Biofuelplants
Certain potential plants wereselected and attempts were made to develop agro-technology for their largescale cultivation (Kumar 1984; Kumar et al. 1995; Kumar 1998; Kumar l996; Kumar1994; Roy and Kumar 1998a)n (Kumar 1995; Kumar 2000). A 50 ha bio-energyplantation demonstration project center has been established on the campus ofthe University of Rajasthan to conduct the experiments on large scalecultivation of selected plants with the objective of developing optimalconditions for their growth and productivity, besides conserving the biodiversity.
Next generation bio-fuelsshall involve technical components :
(a) Biological sciences: Plant biotechnology, Cellular andmolecular biology, microbial/industrial biotechnology.
(b) Chemical technology sciences: catalysis, reaction engineeringand separations.
b) Bioethanolproduction:
The acid pre-treatment of lignocellulosicbiomass for biofuel ethanol production not only enables the release ofmonosaccharides, but also generates several types of compounds, which areinhibitory to yeast.
Furans, like 5-hydroxymethylfurfural (HMF)and furfural, are known to inhibit yeast growth and viability and to reduceethanol productivity.
Thus, faster conversion rates of HMF andfurfural are desirable.
Yeast strains are naturally able to slowlyreduce HMF and furfural to less toxic compounds, however the rate of inhibitorconversion and cofactor utilization are strain dependent (NADPH-dependent).
Dehydrogenase responsible for HMF conversionin S. cerevisiae
3. RESULTS:
3.1 Developmentof biofuel resources:
During last 30 years we have carried out significantinvestigations on biofuels which are summarized here in brief only. Some of theimportant findings of the research work carried out by contemporary researchersand future projects are also reviewed. This paper presents original results aswell as review of research work being carried out in the field.
The selection of biofuel material isof utmost importance. Initial studies of Calvin (1974) concentrated on laticiferousplants. Melvin Calvin in 1980 suggestedto me that to try the laticiferous plants in Rajasthan, whose climate is broadlysimilar to Arizona desert in several respects. We commenced work on laticifers in 1980 itself and at that time Department of Non-conventionalenergy sources (DNES) which was later on elevated to Ministry of Non-ConventionalEnergy Sources supported research projects to us to carry out researches onbiofuels in 5 ha area to begin with which was raised to 50 ha energydemonstration project center (EPDPC). Euphorbialathyris and Euphorbiaanitsyphilitica, Pedilanthustithymaloides, Calotropis procera,Euphorbia royleana, and Euphorbia caducifolia were investigatedin detail. During this period (1970-1990) active research was carried outin in India, USA, Australia and Japan(Kumar, 1984, 2001, 2008 and 2011).
Out of 600 plants screened around 12plants were selected for intensive studies. Two plantsviz Calotropis procera, Euphorbiaantisyphilitica were selected for detailed investigations. Calotropis procera grows wild while Euphorbia antisyphilitica has been introducedfrom Mexico. Detailed studieshave been conducted on the growth and cultivation and improvement of hydrocarbon contents of Calotropis procera and Euphorbia antisyphilitica. 12 accessions of Calotropis procera were analysed and their growth parameters studied at the Energy Plantation Demonstration Centre,University of Rajasthan, Jaipur under Departmentof Biotechnology project Agrotechnology for their improved growth and hydrocarbon yield potential hasbeen documented by Department of Biotechnology in their report (Kumar 2007) .
3.2 Hydrocarbons from plants
Some of the laticiferous plantsidentified by Bhatia et al. (1983) were investigated in detail at Jaipur (Kumar2001b; Kumar 2000; Kumar 1995; Kumar et al. 1995).Certain potential plants wereselected and attempts were made to develop proper agro- technology for theirlarge scale cultivation. Initially work was initiated at 5 ha and subsequentlyextended to the 50 ha EPDPC. In this paper a review of work done is presentedin brief.
Thework done included
i) Hydrocarbon yielding plants,
ii) high molecular weight hydrocarbon yieldingplants,
iii) non edible oil yielding plants
(I) Hydrocarbon yielding plants included:
1. Euphorbia lathyris Linn., 2. Euphorbia tirucalli. Linn., 3. Euphorbia antisyphilitica, Zucc.,4.Euphorbia caducifolia Haines., 5.Euphorbia neriifolia Linn,6. Pedilanthus tithymalides Linn, 7.Calotropisprocera (Ait.)R.Br.,8.Calotropis gigantea(Linn) R.Br.
II) High Molecular Weight HydrocarbonYielding Plants :
Parthenium argentatum Linn.
III) Nonedible oil yieldingplants
1. Jatropha curcas. 2. Simmondsia chinenesis
Considerable work has ben carriedout on these plants (Kumar and Roy 1996; Roy and Kumar 1990; Roy and Kumar1998b; Kumar 1994; Kumar 1995). Investigations on several plant species havebeen carried out at our center including Euphorbialathyris (Garg and Kumar 1989a;Garg and Kumar 1989b; Garg and Kumar 1990b; Garg and Kumar 1987a; Garg andKumar 1989c; Garg and Kumar 1987c; Garg and Kumar 1987c) Euphorbia tirucalli, Euphorbia antisyphilitica (Johari etal. 1990; Johari et al. 1991) Pedilanthus tithymaloides(Rani and Kumar 1994; Rani et al. 1991; Raniand Kumar 1994 ) ; Calotropis procera (Rani et al. 1990); Euphorbia neeriiifolia and E.caducifolia (Kumar 1994; Kumar 1990); Jatropha curcas (Roy 1996; Roy and Kumar1990)and Simmondsia chinensis. Thefollowing aspects have been studied in detail:
(A) Propagation
Regarding environmental variations,the March to October period was best suitable for E.antisyphilitica becausea linear increase in growth was recorded in the period (Kumar, 1990). During these months, maximum sprouting wasobserved in Pedilanthus tithymaloides, E.antisyphiliitca and E.tirucalli. Cuttingsmeasuring around 15 cm in length and 1 cm in diameter gave optimalgrowth. Seeds of Jatropha curcas andE.lathyris also showed maximum germination during these months. Overallgrowth and productivity was lowest in the winter months from November toFebruary. Higher accumulation of hexane extractables corresponded with highertemperatures of the summer season (Johari and Kumar 1992).
(B) Edaphic factors
Among different soil types sand wasbest for the growth of E. lathyris (Garg and Kumar 1990b) and P. tithymaloides (Rani et al. 1991) while red loamsoil was best for E. antisyphilitica. However, for E.lathyris latex contents were maximum on sandgravel. Red soil was rich in nitrate, sodium, potassium and phosphoruspentaoxide (Johari and Kumar 1992). E. antisyphilitica plants wererelatively tall in sandy soil and less branched as compared to red soil. Plants grown in red soil branched moreinstead of increasing much in height. Whendifferent combinations of these soil types were made biomass of E.antisyphiliticawas maximum in red loam+sand+gravel (Johari et al. 1990). While the redloam+sand combination in equal amounts was best for P.tithymaloides (Rani et al. 1990). A mixture ofgravel+sand favored maximum increase in plant height fresh weight and dryweight in E. lathyris (Garg and Kumar 1990b; Kumar and Garg 1995). Environmentalfactors influenced the growth and yield of Calotropis procera (Rani etal. 1990).
C) Fertilizer application
Application of NPK singly or invarious combinations improved growth of all the selected plants. In generalNP combination gave better growth which was only slightly improved by the addition of K forE.tirucalli. When best doses of NPK were applied in differentcombinations like NP, NK, KP and NPK the last combination gave best results inthe form of biomass, latex yield, sugars and chlorophyll in E.lathyris (Gargand Kumar 1990b) and P.tithymaloides (Rani and Kumar 1994). In E. antisyphilitica, however, NPcombination gave best results, followed by NPK for biomass production. Chlorophyll,sugars and latex yield was best in combination (Johri and Kumar 1993).
Addition of farm yard manure (FYM) alone and in combination with urea improved the growth and productivity of E.antisyphilitica,E.lathyris (Kumar and Garg1995), FYM + Urea application improved the productivity in comparison with FYMapplication alone. In E.lathyris addition of FYM increased the plantheight fresh weight and dry weight to varying degrees. Hexane and methanolextractables also increased (Garg and Kumar 1986; Garg and Kumar1987c).Salinity stress studies were also made on Euphorbia tirucalli. Salinitywas applied in the form of irrigation water. Lower concentrations of salinityimproved plant growth of E. antisyphilitica (Johari et al. 1990) but higher concentrations inhibited furtherincrease in growth. Sugars, however, didnot increase in any saline irrigation. A slightly higher level of salinityimpaired chlorophyll synthesis also. At higher level of salinity leaves of E.antisyphiliticabecame yellow and fell down but the stem did not show any visible adverseeffects. E. lathyris could alsotolerate lower salinity levels but its tolerance was lower than E.antisyphilitica. In E.lathyris salinity adversely affected root growth (Johari et al. 1990). P.tithymaloides also exhibited increases in biomassand yield at lower salinity levels and higher concentrations adversely affectedthe plant. Its underground part could tolerateslightly higher salinity concentration (Rani et al. 1991). Saline irrigation was also given withdifferent percentage of FYM added in the soil. Both E.antisyphilitica and P.tithymaloides exhibitedtolerance of higher salinity levels with increasing percentage of FYM in thesoil, biomass sugars, biocrude and chlorophyll all increased in proportion withincreasing FYM levels in the soil and along with saline irrigation. It wasfound in Euphorbia lathyris that up to a certain level FYM causesincrease in overall growth and yield along with different concentrations ofsaline irrigation. Beyond a certain level increased FYM did not improve growthand productivity. P. tithymaloides required still higher percentage ofFYM in the soil for best yield and biomass.Lower salinity levels increased thesugar contents in sand. Higher salineconcentrations adversely affected the chlorophyll contents but with increase inmanure supply the chlorophyll accumulation was promoted in P.tithymaloides. Above ground plant biomass improvedsignificantly with increasing percentages of Field Capacity, maximum being 100 percent FC irrigation. In E. antisyphilitica as well as in P. tithymaoildes plantheight also increased linearlywith increasing soil water status. However, under ground length was found toincrease up to a certain level only. Irrigation beyond an optimum level tendedto reduce biocrude, sugar and chlorophyll in E. antisyphilitica. In P.tithymaloides lowest FC gave maximum yield of HE and chlorophyll. Sugar,however, increased with increasing levels of field capacity irrigation. Percentdry matter yield also decreased with increasing the quantity of irrigationwater to the soil in E.antisyphilitica and P. titymaloides (Raniand Kumar 1994).
(D) Application of growth regulators
Exogenous application of growthregulators has been reported for several horticultural and ornamental plants and sugarcane. In Euphorbia antisyphilitica in the present experimentmaximum plant height was observed with GA3, followed by CCC, NAA, 2,4,5-T andIAA treatment. Spray of growth regulators resulted in enhanced fresh and dryweight production (Johari et al., 1994b). However bio-crude synthesis occurred more with the auxins NAA and IAA inE. antisyphilitica. Out of all the growth regulators employed on P.tithymaoildes, IAA supportedmaximum plant growth interms of fresh weight and dry weight of above ground and under ground plantparts.
2,4,5-T showed minimum plant growth,and certain nodular structures were observed on the stem of the plants.Biocrude yield was best in IAA followed by 2,4,5-T, GA3, CCC, NAA and control. Application of growthregulators on P. tithymaloides resulted in a slight decrease inchlorophyll, whereas on E.lathyris they induced favorable resultsregarding chlorophyll(Garg and Kumar 1987b). In E.lathyris IBA caused maximumfresh weight productivity followed by IAA, GA3 and NAA. NAA sprayed plants exhibited more production of HE. A favorable influence of growth regulatorswas also observed in sugar yield maximum with NAA followed by IBA, GA3 and IAA (Garg and Kumar 1987c). Thecultivation of these plants suffers from plant pathogenic diseases affecting atthe root level. Investigations on pathogenicity and control aspects of Charcoalrot of E.lathyris (Garg and Kumar 1987c); E.antisyphilitica (Johriand Kumar 1993) were also carried out.
(E) Micropropagation
Plant tissue culture has been successfullyemployed to achieve rapid clonal propagation of E.lathyris (Kumar and Joshi,1982); Pedilanthustithymaloides (Rani and Kumar 1994 ) and E.antisyphilitica (Johari and Kumar 1994). Likewisepropagation of jojoba has also been carried out (Roy 1972a). Jatropha curcas L. is potential diesel fuel yielding plantand details about this are given in Roy and Kumar, 1988 and Roy, 1999(Roy andKumar 1998b).
Developmentof wasteland
Aprotocol was set up for developing the wasteland following the three tier systemin which small shrubs, shrubs and trees were used at a close spacing and this yielded a drymatter production of over 40 dry tonnes in a three year rotation . The Euphorbiaantisyphilitica in the lower tier, Jatropha curcas in the middletier and Acacia totilis in the upper tier were used to colonize theEPDPC. The picture below represents the area as seen originally in Figure 1 and2 which has been developed at EPDPC as greenland from the wasteland.
|
Figure 1: Energy plantation Demonstration Projekt Center (EPDPC) University of RajasthanJaipur 1984. Barren Land with only one tree (Holoptelia integrifolia). |
Figure 2: Another View of wasteland at EPDPC. Pitting was done at 1 Meter x 1 Meter For Plantation.
|
|
Figure 3: Euphorbia Antisyphilitica Nursery stage, with close spacings. |
Figure 4: Calotropis Procera a hydrocarbon plant used to colonise |
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Figure 5: Euphorbia tirucalli |
Figure 6: Euphorbia caducifolia |
|
Figure 7: Euphorbia neeriifolia |
Figure 8: Jatropha curcas and Calotropis procera in background |
|
Figure 9: Euphorbia antisyphilitica and Calotropis procera |
Figure 10: Euphorbia antisyphilitica and Jatropha curcas in background |
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Figure 11: Three tier system with E.antisyphilitica in foreground and Acacia tortilis in background |
Figure 12: A well developed EPDPC following the three tier system. |
The possibility of conversion ofbiomass into liquid fuels and electricity will make it possible to supply partof the increasing demand for primary energy and thus reduce crude petroleumimports which entail heavy expenditure on foreign exchange. The familiesEuphorbiaceae ( Euphorbiaantisyphilitica, E.tithymaloides, E. caducifolia E. royleana E. neerifolia etc.and Ascelpiadaceae ( Calotropis gigantea and C. procera ) which have been worked out in previous years(Kumar 2000) will form the basis for further studies.
Fast pyrolysis is a promisingpre-treatment technology that converts solid biomass into an easier totransport and to process liquid energy carrier. One of the advantages of thefast pyrolysis process is that it produces a liquid fuel with a high energydensity of ca. 22 GJ/m3 compared to ca.6 GJ/m3 for wood chips. This is beneficial, especially when biomass resourcesare remote from where the energy is required: the liquid can be readily storedand transported. Another pro of pyrolysis is that the liquid product is cleanerthan the original feedstock. Minerals and metals in the feedstock becomeconcentrated in the solid by-product (char), because of the relatively lowprocess temperature (ca. 500 °C).
Biofuelshold out the promise of a win-win-win solution
Biofuels will reduce greenhouse gasemissions, promote energy independence, and encourage rural development.
This enthusiasm translates into significant governmentsupport. Annual global subsidies for biofuel production were $11 billion in2006 and could rise to $50 billion by 2020.
Many governments have enacted new pro-biofuelpolicies in recent years. Developed country governments like the UK and EU haveset consumption targets for biofuels
Nextgeneration biofuels can reduce negativeimpacts.
The first to arrive will be lignocellulosicbiofuels made from the lignin and cellulose in the cell walls of plants.
The feedstocks for these biofuels – trees, grasses,or leftover plant materials – have several potential advantages.
They require less intensive agriculture andmay be grown on “marginal” land, reducing competition for resources.
Lignocellulosic biofuels could be made fromagricultural or forestry residues such as rice husks and corn stover.
A 2007 UN report estimated that thesebiofuels would be
commercialised by 2015 and become competitivewith petroleum-based fuels in the next 10-15 years.
3.3 Jatropha curcas:
Jatropha grows wild in south east Rajasthan which lies on south east sideof Aravalli hill range which roughlydivides the state in semi-aridand arid regions. Jatropha curcas has now being extensively grown in India under the Department ofBiotechnology supported micro mission projects with an object to identify,characterize and multiply high yielding strains and study their growth andproductivity under different agro climatic conditions. The districts ofBanswara, Bhilwara, Udaipur, Pali, Rajsamand, Sirohi have huge strands of Jatropha growing under natural conditions. Adetailed survey was carried out in these areas. 98 accessions were collected and analyzed for their oil contents. Fouraccessions having oil contents more than 35 percent were selected formultiplication at the Energy Plantation Demonstration Centre, University ofRajasthan, Jaipur under Department of Biotechnology supported micro missionprogramme.
Nursery techniques for large scaleplantation of elite strains have been developed. An area of 35 ha has been plantedwith Jatropha curcas with the highyielding strains identified during the course of investigation. The plants have shown great degree of geneticdiversity. The morphological parameters have been employed to characterizeinitial growth of the plants in the nursery stage. Some of the plants in their second year ofgrowth have shown flowering and fruiting during moths of September to January.Application of fertilizers and proper irrigation schedule has improved thegrowth and productivity of plants. A detailed survey was carried out in Udaipurdistrict. Several trees have attained a height of 4 to 10 meters and a girth of0.5 to 1 meter. Such trees have a yield potential of 5 to 15 kg of seeds inextended seed bearing season (Kumar 2011).
3.4 Possiblealternatives:
Oil yielding crops: Europe hasconcentrated oil yielding crops like raps ( Brassicarapa ) in Gerrmany, and soybean oilis used in USA for biofuel. Author himself witnessed buses in campus of University of Illinois, Urbana ChamapaignCampus, USA (Fig 12)
Fig 12: Thereare three alternatives for mature biomass
Bioethanolfrom corn
Fig. 13. Soyabean cultivation in USA in a private farm, abus being run on soybean diesel, Biofuel have closed cycle and dont add carbonto atmosphere and a petrol pump selling bio-diesel based on raps oil inGermany.
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Fig. 14 Morrow Plots of Maize |
Fig. 15 Corn Ethanol at Petrol pumps in USA |
Future of bioenergy:
In a number of scenarios of theglobal food and agriculture system in 2030, we examine to what extent increasesin livestock and crop productivity, and changes in human diets, may expand thebioenergy potential. The results from the scenarios indicate that if the recentprojections of global agriculture made by the FAO come true, the prospects forbioenergy plantations will be less favorable. In our scenario depicting the FAOprojections, it is estimated that total agricultural land area globally willexpand from current 5.1 billion ha to approximately 5.4 billion ha in 2030, leavinglittle room for a major expansion of bioenergy plantations(Wirsenius 2003).
Lignocellulosic biofuels:
Currently, cellulosic biofuels andalgal biodiesels are prominentbiological approaches to sequester and convert CO2. Ethanol andbiodiesel are predominantly produced from corn kernels, sugarcane or soybeanoil create food vs fuel competition and destabilize land use pattern foragriculture. In order to avoid this another biofuel feedstock,lignocelluloses—the most abundant biological material on earth is beingexplored. Lignocelluloses is everywhere—wheat straw, corn husks, prairie grass,discarded rice hulls or trees. The race is on to optimize the technology thatcan produce bio-fuels from lignocelluloses sources more efficiently—and biotechcompanies are in the running. There is campaign, which advocates that 25% of US energy come from arable land by2025. The EU had called for a threefold increase in bio-fuel use by 2010, to 5.75% of transportation fuel.
Whereas starch is soft, lignocelluloses, the maincomponent of the plant cell wall, has evolved to resist degradation. Itconsists of mostly hemicelluloses and cellulose—glucose chains stacked intocrystalline fibrils, largely impenetrable to water or enzymes. Lignin, a morecomplex macromolecule, makes up much of the rest. Wood, one potential source oflignocelluloses, for example, typically consists of 40–50% cellulose, 25%hemicelluloses and 25–30% lignins; the rest is made up of cell wall proteinsand pectins. One approach to extract fuel from lignocelluloses borrowstechnology from the coal and oil industry to convert plant material into‘syngas,’ mainly carbon monoxide and hydrogen. Syngas is then converted intoethanol or biodiesel by the Fischer-Tropsch process, invented in Germany in theearly 1900s, usually using iron or cobalt catalysts. Another approach, popularin the United States, relies on enzymes and fermentation to produce cellulosicethanol.
Fig.16Composition of Cell Wall
Why is cellulose so difficult to turn into fermentablesugars?
• Starch is a storage polysaccharide designed by natureas a food reservoir
• Cellulose is part of a lignocellulosic compositedesigned by nature to resist degradation
_
Hydrocarbons
from plants
Some of the laticiferous plants
identified by Bhatia et al. (1983) were investigated in detail at Jaipur (for
review see (Kumar 1995; Kumar 2000; Kumar 2001a) .
Certain potential plants were
selected and attempts were made to develop proper agro- technology for their
large scale cultivation. Initially work was initiated at 5 ha and subsequently
extended to the 50 ha EPDPC.
Growing Interest By End Users
•
Pratt&Whitney Canada: investigating
biofuels from algae and Jatropha.
•
Boeing: algae will be 1º
feedstock for aviation biofuels within 10-15 years.
•
Air France-KLM: agreement with
Algae-Link to procure algae oil to be blended with conventional jet fuel.
•
JetBlue, Airbus, Honeywell
and the International Aero Engines partnership: replace up to 30 percent of jet
fuel with biofuels produced from algae and other non-food vegetable oils.
•
Air New Zealand: test Jatropha as
a fuel
Targets
now promoted by the US Department of Energy (DOE) call for 30% of today’s fuel
use to be supplanted by 2030 with ethanol— 60-billion gallons of it each year.
Triglycerides from oil seed crops can’t come close to meeting U S diesel demand
(60 billion gal/yr) as agricultural productivity can’t be diverted from the
food supply.
Under that scenario, much of the fuel is slated to come
from lignocelluloses, which the DOE expects will become cheaper to make as the
technology improves. Researchers at the US National Renewable Energy Lab (NREL,
Golden, Colorado) estimate the capital cost of a cellulosic biomass–converting
facility which would yield 50-million gallons of ethanol per year, at $215
million—about three- to fourfold more expensive than a corn grain ethanol plant
with the same yield.
According to the US Renewable Fuels
Association, a trade association for the US ethanol industry, annual production
totaled 3.9-billion gallons last year, up 15% from 2004. But estimates indicate
that new plants to produce another 1.9-billion gallons a year are under
construction and will come online by 2007. However at present, less than 1% of
the United States’ fuel stations sell ethanol. Targets now promoted by the US
Department of Energy (DOE) call for 30% of today’s fuel use to be supplanted by
2030 with ethanol—60-billion gallons of it each year.
Despite the fact that biomass
represents about one third of the energy consumption in developing countries,
it is not taken very well into account in energy studies. A set of factors
explain the slow growth on the biomass utilization . They include:
1.
High
costs of production
2. Limited
potential for production
3. Lack
of sufficient data on energy transformations coefficients.
4. Low energy efficiency
5. Health
hazard in producing and using biomass.
In the large scale use of biomass
for energy risks are insecurity in raw material supply and prices, doubts about
adequate quality assurance and hesitance for a wider acceptance by the diesel
engine manufacturers, missing marketing strategies for targeting biodiesel
differential advantages into specific market niches and last not least missing
legal frame conditions similar to the clean air act in the USA.
5. ACKNOWLEDGEMENTS
The research grants from Govt of India Department of Biotechnology for research in the field are gratefully acknowledged. The
constant encouragement of Late Professor Dr. K-H. Neumann
is gratefully acknowledged. The
support from Professor Dr. Sven Schubert Institut
fur Pflanzenernaehrung der Justus Liebig Universitat Giessen, Germany and
award of fellowship by Alexander von Humboldt Foundation is gratefully acknowledged.
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