Modern bioenergy technologies and biofuels are relatively benign from environmental view point and produce very little pollution if burned correctly and completely. The creation of new employment opportunities within the community and particularly in rural areas is one of the major social benefits from the exploitation of biomass for energy, industry and environment. Use of biomass for energy and industry allows a significant quantity of hydrocarbons to be consumed without increasing the CO2 content of the atmosphere and thus makes a positive contribution to the Greehouse effect and to the problems of "global change" as occurs in both industrialized and developing countries. Further advantages from utilization of biomass include : liquid fuels produced from biomass contain no sulfur, thus avoiding SO2 emissions and also reducing emission of N0x.
Improved agronomic practices well managed biomass plantations will also provide a basis for environmental improvement by helping to stabilize certain soils, avoiding desertification which is already occurring rapidly in tropical countries.
Modern biomass use implies higher conversion efficiencies than traditional biomass, or production of electricity or liquid biofuel, both to use more efficiently the resource and to mitigate climate change. For some production such as ethanol, heat or heat and power for medium and large scale consumers South-South or North–South technology transfer can already be considered. Limiting factors are then generally no longer of technological nature. New investments schemes are then often required. But for small scale users in industries and in villages some improvements and research are still necessary.
This is discussed by taking several examples: (1) production and use of crude vegetable oil from Hardnut (Jatropha curcas) and Mamona (Ricinus communis) in semi arid zones; are considered improvement of oil yields per hectare, reduction of harvesting cost of seeds, reduction of adaptation costs of engines, increase of engine longevity etc.); (2) heat generation for fruit drying, (3) heat and rural electricity production with agricultural residues and savannah grass converted into pellets and charcoal ;
Biodiesel production :
A recent World Bank report concluded that "Energy policies will need to be as concerned about the supply and use of biofuels as they are about modern fuels (and) they must support ways to use biofuels more efficiently and in sustainable manner. Although there is significant volume of biodiesel already produced in <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Europe there are remaining risks slowing down the further expansion to the target set by the European Commission to reach 5% market share in transportation fuels by the year 2000".
These 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, mission marketing strategies for targeting biodiesel differential advantages into specific market niches and last not least missing legal frame conditions similar to clean air act in the USA.
1.3 Biomass as potential resources :
Biomass resources are potentially the worlds largest and sustainable energy source a renewable resource comprising 220 billion oven dry tones (about 4500 EJ) of annual primary production. The annual bioenergy potential is about 2900 EJ though only 270 EJ could be considered available on sustainable basis and at competitive prices.
Most major energy scenarios recognize bioenergy as an important component in the future worlds energy. Projections indicate the biomass energy use to the range of 85 EJ to 215 EJ in 2025 compared to current global energy use of about 400 EJ of which 55 EJ are derived from biomass(2).
1.1 Biomass comprising all forms of matter derived from the biological activities taking place either on the surface of the soil or at different depth of the vast body of water lakes, river, ocean.
1.2 Ovington (1957) defined biomass as dry matter production. Currently it is defined as living matter or its residues which are perpetual or a renewable source and common examples of biomass include wood, grass, herbage, grains or bagasse.
1.3 Assessing the total above ground biomass, defined as biomass, when expressed as dry weight per unit area, either total biomass or by components (eg. leaves, branches and bole), is a useful way of quantifying the amount of resource available for traditional uses. The main sources of biomass can be classified in two groups one is waste materials including those derived from agriculture, forestry and municipal wastes.
1.4 The study area is situated in semiarid region and most plant species appear in the region in their respective growth periods. A three tier system was developed for biomass production i.e. herbaceous, shrub and tree biomass. Most plant species are herbaceous in nature and appear during rainy season. They are the first colonizers and are generally herb which have important uses (Woodard and Prime, 1993; Morgana et al., 1994 and Houerou and Houerou, 2000).
1.5 Biomass can be converted in to solid, liquid and gaseous forms through biological thermochemical route for deriving thermal electrical and mechanical forms of energy. Thus biomass offers multiple options for transition from the use of conventional, exhaustible and polluting forms to non-conventional, renewable, non-exhaustible, non polluting and perennial forms so as to ensure sustained growth and economic development (Verma et al., 1996; Dabson et al., 1997 and Spalton, 1999).
1.6 Some herbaceous and shrub plants are also important for biomass production in the form of bioenergy (Sampath et al., 1983; Vasudevanm and Gujral, 1984; Singh et al., 1987; Morgana et al., 1994; Prine and Woodard, 1994; Pedreira et al., 1999 and Vazquez-de-Aldana et al., 2000).
1.7 Beside the solid biomass some plant species are important for liquid biomass in form of hydrocarbon and non edible oil production, which provides an alternative source of petroleum (Calvin 1979; Hall 1980;Eilert et al 1985).
1.8 Present studies were conducted on characterization of bio-energy resources in the semi arid region of Rajasthan because the growing demand for fuel wood as a result of rapid population growth has made it increasingly difficult for many people in this region to meet their basic energy need.
The state of Rajasthan is situated between 23°3’N and 30°12’ N latitude and 69°30’ and 78°17’ E longitude. The total land area of the state is about 3,42,239 km2, out of which about 1,96,150 km2 is arid and rest is semi-arid. This arid and semi-arid wasteland of is rich in biodiversity. During present investigation studies were conducted on characterization of bio-energy resources in the semi arid region of Rajasthan. 230 plants species were characterized and out of them 60 plant species were selected for dry matter production, 11 plants were characterized for non-edible oil production and 14 plants were characterized for hydrocarbon production. With the growing demand for fuel wood these plants possibly use as bio-energy sources in their natural habitat.
Out of the 60 plants following plant species were suitable for biomass production due to their high dry matter contents. These plants included (weights in g/plant) Echinops echinatus Roxb. : 133.66; Verbesina encelioides (Cav.) Benth.&Hk.: 80.33; Calotropis procera (Ait) R.Br.: 648.33; Leptadenia pyrotechnica (Forsk.) Decne. : 486.66; Sericostoma pauciflorum Stocks. : 352.66; Amaranthus spinosus Linn. : 167.66; Withania somnifera (L.) Dunal. : 350; Lepidagathis trinervis Wall. ex Nees. : 204; Lantana indica Roxb. : 373.33; Aerva tomentosa (Burm.) Juss. : 283.33; Croton bonplandianum Baill. : 155.33; Abutilon indicum (L.) Sweet. : 1453.33; Acacia jacquemontii Benth. : 693.33; Crotalaria burhia Buch.-Ham. ex Benth. : 266; Saccharum bengalense Retz. : 1900 and Artemisia scoparia Waldst. et Kit. : 90. The plant biomass in terms of fresh weight and dry weight was recorded in all the three seasons.
Hydrocarbons were extracted by using two different solvent hexane and methanol. Among the different plant extractions Euphorbia antisyphilitica Zuce. showed the best extraction results in hexane 8.5% and Calotropis procera (Ait.) R.Br. showed best results in methanolic extraction 33.8%(Table 1.)
Percent hydrocarbon contents in above ground part of different plants in Hexane extraction (HE) and Methanolic extraction (ME)
Name of the plant
Calotropis procera (Ait.) R.Br.
Euphorbia antisyphilitica Zuss.
Euphorbia hirta Linn.
Euphorbia prostrata Ait.
Pergularia daemia (Forsk.) Chiov.
Padilanthus tithymaloides var
Padilanthus tithymaloides var
Padilanthus tithymaloides var
Non-edible oil content in seeds of different plant species
Name of the plants
Percent seed oil
Argemone mexicana Linn.
Azardirachta indica A. Juss
Citrullus colocynthis (Linn.) Schrad.
Cleome viscosa Linn.
Pongamia pinnata (L.) Pierre.
Jatropha curcas Linn.
Ricinus communis Linn.
Sesamum indicum Linn.
Xanthium strumarium Linn.
Martynia annua Linn.
Calotropis procera (Ait.) R.Br.
1.4 Calotropis procera carried in Arid and semi arid lands which occupy one third of the earth's surface. Indian arid zone occupies an area of about 0.3 million sq. km. 90 percent of which about 2,70,000 sq. km. is confined to north west Indian covering most of Western Rajasthan, part of Gujarat and small portions of Punjab and Haryana. India with its vast expanse of wasteland unsuitable for agricultural production (nearly 180 million ha) could be considered for economically viable production of biofuels.
1.5 Productivity :
a. If 10,000 plants are grown in one ha at 1mx1m distance and average plant weight is 20kg then the fresh biomass produced will be 2,00,000 kg/ha/annum and the dry biomass will be 40,000 kg or 40 tonnes/ha/annum (20% of fresh wt.). This will yield 4-4.8 tonnes / ha/annum maximum biocrude (10-12%). If the cost of biocrude is Rs. 30/- per kg then the total value will be Rs. 1,20,000. The remaining biomass (90%) will be 36 tonnes/ha/annum and if it is Rs. 1/- per kg then its value will be Rs. 36,000 thus the total amount will be 1,20,000+36,000 = Rs. 1,56,000.00.
b. If, 5,000 plants are grown in one ha at 2mx2m distance and average plant weight is 100kg then the fresh biomass produced will be 5,00,000 kg/ha/annum and the dry biomass will be 100,000 kg or 100 tonnes/ha/ annum (20% of fresh wt.). This will yield 10 tonnes/ha/annum maximum biocrude (10%). If the cost of biocrude is Rs. 30/- per kg then the total value will be Rs. 3,00,000. The remaining biomass (90%) will be 90 tonnes/ha/annum and if it is Rs. 1/- per kg then its value will be Rs. 90,000 thus the total amount will be 3,00,000+90,000=Rs, 3,90,000.00
1.6 Already European countries mainly Italy, Germany and Austria are leading in Biodiesel production nearing 500,000 tons in 1997 out of which 2,50,000 tonnes was produced in France. (1) The production capacity of biodiesel in Germany was fully utilized in 1997, the sold quantity amounting to roughly 100,000 t. The technologies for producing bio-oil are evolving rapidly with improving process performance, larger yielding and better quality products. The present paper shall discuss problem and strategies for use of biomass in developing countries.
Biomass contributes a significant share of global primary energy consumption and its importance is likely to increase in future world energy scenarios. Current biomass use, although not sustainable in some cases, replaces fossil fuel consumption and results in avoided CO2 emissions, representing about 2.7% to 8.8% of 1998 anthropogenic CO2 emissions. The global biomass energy potential is large, estimated at about 107 EJ/a. Hence, biomass has the potential to avoid significant fossil fuel consumption, potentially between 17% and 36% of the current level and CO2 emissions potentially between 12% and 44% of the 1998 level. Modern biomass energy use can contribute to controlling CO2 emissions to the atmosphere while fostering local and regional development. There is significant scope to integrate biomass energy with agriculture, forestry and climate change policies. Further the advantages from utilization of biomass include: liquid fuels produced from biomass contain no sulphur, thus avoiding SO2 emissions and also reducing emission of NOx. The production of compost as a soil conditioner avoids deterioration of soil.
Improved agronomic practices of well managed biomass plantations will also provide a basis for environmental improvement by helping to stabilize certain soils, avoiding desertification which is already occurring rapidly in tropical countries. The creation of new employment opportunities within the community and particularly in rural areas will be one of the major social benefits.
The present investigations carried out with an object of biomass production and utilization in less fertile areas, will provide satisfactory answers to the double challenge of energy crisis and forced deforestation in the country and semi-arid and arid regions of Rajasthan. Kumar (2001) has suggested that biomass from plants can be converted into liquid fuels. This will make it possible to supply part of the increasing demand for primary energy and thus reduce crude petroleum imports, which entail heavy expenditure on foreign exchange. Several families widely growing in Rajasthan have great potential as renewable source of energy. Euphorbiaceae (Euphorbia antisyphilitica, E. tithymaloides, E. caducifolia, E. lathyris, E. neerifolia etc. Aselipiadaceae (Calotropis gigantea and C. procera) Asteraceae and Apocynaceae have large number of valuable plants (Kumar and Vijay, 2002 and Vijay et al., 2002).
Characterization of biomass production in wastelands during the present investigation offers a database of potential plants to be used in arid and semiarid regions and a three tier system has been developed.
However further studies are needed to establish gene pool database on the basis of RFLP and AFLP so that it could be used for genetic transformation studies. Which can help for development of bioenergy source from these arid and semiarid wasteland of Rajasthan.
July 5, 2005
Cornell ecologist's study finds that producing ethanol and biodiesel from corn and other crops is not worth the energy
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Chris Hallman/University Photography
Ecologist David Pimentel, shown here pumping gas, says that his analysis shows that producing ethanol uses more energy than the resulting fuel generates. Copyright © Cornell University
ITHACA, N.Y. -- Turning plants such as corn, soybeans and sunflowers into fuel uses much more energy than the resulting ethanol or biodiesel generates, according to a new Cornell University and University of California-Berkeley study.
"There is just no energy benefit to using plant biomass for liquid fuel," says David Pimentel, professor of ecology and agriculture at Cornell. "These strategies are not sustainable."
Pimentel and Tad W. Patzek, professor of civil and environmental engineering at Berkeley, conducted a detailed analysis of the energy input-yield ratios of producing ethanol from corn, switch grass and wood biomass as well as for producing biodiesel from soybean and sunflower plants. Their report is published in Natural Resources Research (Vol. 14:1, 65-76).
In terms of energy output compared with energy input for ethanol production, the study found that:
- corn requires 29 percent more fossil energy than the fuel produced;
- switch grass requires 45 percent more fossil energy than the fuel produced; and
- wood biomass requires 57 percent more fossil energy than the fuel produced.
In terms of energy output compared with the energy input for biodiesel production, the study found that:
- soybean plants requires 27 percent more fossil energy than the fuel produced, and
- sunflower plants requires 118 percent more fossil energy than the fuel produced.
In assessing inputs, the researchers considered such factors as the energy used in producing the crop (including production of pesticides and fertilizer, running farm machinery and irrigating, grinding and transporting the crop) and in fermenting/distilling the ethanol from the water mix. Although additional costs are incurred, such as federal and state subsidies that are passed on to consumers and the costs associated with environmental pollution or degradation, these figures were not included in the analysis.
"The United State desperately needs a liquid fuel replacement for oil in the near future," says Pimentel, "but producing ethanol or biodiesel from plant biomass is going down the wrong road, because you use more energy to produce these fuels than you get out from the combustion of these products."
Although Pimentel advocates the use of burning biomass to produce thermal energy (to heat homes, for example), he deplores the use of biomass for liquid fuel. "The government spends more than $3 billion a year to subsidize ethanol production when it does not provide a net energy balance or gain, is not a renewable energy source or an economical fuel. Further, its production and use contribute to air, water and soil pollution and global warming," Pimentel says. He points out that the vast majority of the subsidies do not go to farmers but to large ethanol-producing corporations.
"Ethanol production in the United States does not benefit the nation's energy security, its agriculture, economy or the environment," says Pimentel. "Ethanol production requires large fossil energy input, and therefore, it is contributing to oil and natural gas imports and U.S. deficits." He says the country should instead focus its efforts on producing electrical energy from photovoltaic cells, wind power and burning biomass and producing fuel from hydrogen conversion.
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