· Biofuels offer clear advantages in terms of greenhouse gas emissions, but do they perform better when we look at all the environmental impacts from a life cycle perspective? To compare the environmental impacts and externalities of biodiesel and fossil diesel, these fuels and their impacts are assessed in a detailed way, combining Life Cycle Assessment (LCA) tools and externality assessment tools.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
· Both environmental analyses require an objective basis for comparison, the so-called functional unit, which, reflects the function of the two fuels. According to Vito-measurements, it takes litre of biodiesel in relation to 0.95 litre of fossil diesel fuel to drive with an identical car and the same conditions (I). So both for the LCA and externality analysis litre of biodiesel is compared with 0.95 litre of fossil diesel fuel. This functional unit is consistent with the vehicle/km used in external cost analysis for the comparison of different fuels and technologies.
· Belgium was considered to be the geographical reference area for the biodiesel life cycle. With regard to fossil diesel fuel, West European conditions were taken into account. Both assessments start at the extraction of primary raw materials and conclude with the combustion of the fuels in the car engine.
· The paper uses interim results of this project to compare diesel and biodiesel.
· Figure I shows the life cycle trees for both fuel cycles. For all these steps, the most important emissions have been quantified.
2. COMPARISON BASED ON STANDARD LCA
· The analysis is based upon the LCA methodology described by ISO in its 14040 standard (2)
· The primary concern of the LCA is the question as to whether or not the production of biodiesel is comparable to the production of fossil diesel fuel, from an environmental point of view, taking into account all stages of the life cycle of these two products. The different environmental impacts are weighted based on traditional LCA techniques.
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Figure 1: Life cycle tree for fossil diesel fuel and biodiesel
· One of the most important interim results from the impact assessment is that the agricultural processes of the biodiesellife cycle chain contribute significantly to most impact categories considered in the study. More specifically, the production and the use of chemical fertilisers have an important contribution.
· When comparing the two ecobalances, it is clear that the biodiesellife cycle only has a better effect score for the use of fossil fuels and for global warming. The better environmental score for the greenhouse effect is caused by the fact that rapeseed assimilates CO2 during its growth. Indeed, the CO2 balance has been closed in the life cycle inventory part of biodiesel; only the CO2 emissions with a 'fossil' origin have been taken into account. Considering the use of fossil fuels, it goes without saying that the biodiesel scenario consumes less fossil fuel in comparison with the fossil diesel scenario during its life cycle.
· As a result of the final valuation (3) the environmental index of biodiesel is a factor 2 higher than the one for fossil diesel (Fig. 2). Taking account of all the assumptions made at the moment, we could conclude that fossil diesel fuel is environmentally better than biodiesel. However, not all impact categories were weighted during valuation and moreover weighting factors, to a large extent, have a rather subjective nature.
Figure 2: Result of LCA-valuation
3. COMPARISON BASED ON EXTERNALITIES
3.1 The Externe methodology
A very sophisticated method to weigh the different types of impact categories is to make a detailed assessment of the environmental damages caused by the emissions of the biodiesel and diesel fuel chain. To this purpose, Vito uses the ExternE (Externalities of Energy) accounting framework, developed under the Joule research project of the EC since 1992 (4). These days it is widely recognised as the most complete and up to date methodology for the quantification of external costs (damages) from energy and transport, as it integrates a large amount of European and US scientific data and knowledge. It applies the impact pathway approach for a detailed and systematic assessment of the long way from an emission or burden to an impact and damage (Fig. 3). To this purpose, site and technology dependent emissions are quantified; dispersion of these emissions is modelled using local and regional dispersion models. By means of doseresponse functions, the impacts on public health, agriculture, buildings and ecosystems are being quantified. For global warming, specific models are being used to quantify the physical impacts. In a last step, these impacts are valued based on market prices or results from 'willingness to pay' studies. To date, an accounting framework is available for the quantification of site and technology specific damages from the most important energy related emissions, including particles, SO2, NOx, CO, voc, benzene, and greenhouse gasses.
Figure 3: The ExtemE methodology - impact pathway damage function approach
3.2 Interim results: externalities for diesel and biodiesel
For both fossil and biodiesel, damages from particles on public health are the most important external cost category (Fig. 4). This reflects the growing concern over recent years about the impact from particles, sulphates and nitrates on health, especially with respect to chronic mortality. Its valuation takes the number of year lost into account. The emissions of particles come for 90 % from the use phase and because the impacts depend very much on population densities near to the roads. Table I shows a wide range for this pollutant. One has to take care for the comparisons of the fuels because potential differences in the nature and size of the particles from diesel and biodiesel are not fully reflected in these interim results and further research is needed. Impacts from SO2 and NOx are especially public health impacts from sulphates and are less location or technology specific. The evaluation of the contribution of VOC to photochemical oxidation (ozone) is based on a European single average value, which hides a large but unknown variation. The marginal contribution of NOx emissions in Belgium to ozone formation is considered to be zero, based on results for Belgium from ozone models. Comparing these results for Belgium with literature on air-borne emissions for the whole life cycle for biodiesel and diesel confirms our conclusions
Figure 4: External costs of diesel and biodiesel, following the ExtemE 1997 methodology
Table I: The following table shows the externalities for the different emissions for biodiesel and fossil diesel fuel
· The main conclusion is that, compared to the private production costs, external costs are high for both diesel and biodiesel. In comparison to fossil diesel, total external costs of biodiesel are 5% tot 20 % lower, depending on different assumptions. One has however to take into account that a number of indicators for which biodiesel performs worse (impacts on water, eutrophication, acidification and photochemical oxidant formation) have not or only partly been quantified and monetised. Figure 4 shows that the total social costs (private production costs + external environmental damage cost) of biodiesel are higher than for fossil diesel. Indeed; the private costs for biodiesel are substantially higher than for diesel, which is not completely compensated by somewhat lower environmental costs.
· Comparison with other fuels (petrol, LPG) will be elaborated.
1.1 Out of the total land area of India, measuring 3,29 million ha. (mha), 150 m ha. is uncultivated and 90 mha. is categorized as wasteland. The broad subdivision of the wasteland 1S categorized as saline and alkaline, wind and water eroded land forming considerable part of wasteland.
1.2 The process of regeneration of vegetation in degraded and denuded land, representing virtual sand dunes providing an insight into regeneration pattern and biodiversity of the region.
1.3 Complete vegetation pattern of Rajasthan has been studied (1, 2, 3, 4) and succession using hydrocarbon yielding plants has been established at energy plantation demonstration project centre (EPDPC) (5).
1.4 Present investigations were undertaken with an object to study colonizing wasteland under protected and natural condition.
The annual photosynthetic production of biomass is about eight times the worlds total energy use. Indian arid zone covers an area of about 0.3 million sq.km. The state of Rajasthan has total land area of about 3,42,274 Km2 out of which about 96,100 km2 is arid and rest semi arid. 90 million ha of area in India is wasteland around 60 percent of it lies in semi arid region. National remote sensing agency (NRSA) has revealed that during the period 1972-1975 and 1980-82 there has been a loss of 9 million ha of tree cover i.e. an average of 1.3 million ha per year. Out of total forest cover of 64.2 million ha only 36.14 million ha is adequately covered. Thus the effective forest cover is limited to 10.88 percent of geographical area of the country (3,27 million ha). According to National Firewood study committee (1982) the total requirement of fuel wood is around 133 millino tonnes where as annual availability is only about 49 million tonnes per year. Plantation in 15-20 million ha is required to meet this shortage. Total non forest land in India is about 93.69 million ha most of it is uncultivable. Raising energy plantations in the wastelands can provide non-exhaustible non polluting and renewable source of Bio-energy. Biomass energy crops for wastelands were screened and improved. A model system has been developed for the semi arid and arid regions which can be used globally specially in developing countries.
Detailed investigations were carried out on the process of wasteland colonization utilizing the
i) hydrocarbon yielding plants, ii) high molecular weight hydrocarbon yielding plants, iii) non edible oil yielding plants, iv) short rotation fast growing energy plants.
(I) Hydrocarbon yielding plants included :
1. Euphorbia lathyris Linn.
2. Euphorbia tirucalli Linn.
3. Euphorbia antisyphilitica Zucc.
4. Euphorbia caducifolia Haines.
5. Euphorbia neeriifolia Linn
6. Pedilanthus tithymaloides Linn/
7. Calotropis procera (Ait.) R. Br.
8. Calotropis gigantea (Linn) R. Br.
(II) High molecular weight hydrocarbon yielding plants :
1. Parthenium argentatum Linn.
(III) Non edible oil yielding plants.
1. Jatropha curcas L
2. Simmondsia chinenesis (Link) Schneid.
(IV) Short rotation energy plants
1. Cassia siamea Lam.
2. Acacia tortitis (Forsk) Hayne
Investigations on several plant species have been ; carried out at our center including Euphorbia lathyris Euphorbia antisyphilitica; Pedilanthus tithymaloides; Calotropis procera; Euphorbia neeriifolia and E. caducifolia and Simmondsia chinensis.
2. MATERIAL AND METHODS:
2.6 Representative soil of the experimental area \ was analysed chemically. Table 1 (8).
3. RESULTS AND DISCUSSION:
3.1 The early colonizers :
Some of the early colonizers including small ephemerals include: Polygala erioptera DC.; Polycarpaea corymbosa (L.) Lamk. ; Gisekia phamacioides L ; Mollugo cerviana (L.) Ser. ; Side ovals Forsk. ; Corchorus tridens L. ; Triumfetta pentandra A. Rick. ; Indigofera essiliflora DC. ; I. linnaei Ali. These plant species have their value as initial colonizer and are not suitable as biomass resource because" their yield potential is very low. These early colonizers provide helpful association for any subsequent plant to come in the succession like Artemisia scoparia Waldst. ; Farsetia hamiltonii Royle. ; Tephrosia purpurea (L.) Pers ; Citrullus colocynthis (L.) Schrad.; Boerhavia diffuse L. and other herbs.
Among the shrub species which came in the next season Leptadenia pyrotechnica (Forsk.) Decene.; Calotropis procera (Ait.) RBr.; Side cordifolia L. ; Crotalaria burhia Buch. - Ham. ; Verbesina encelioides (Cav.) Benth.&Hook. and grass Saccharum munja L. were abundant. In the second year of growth the tree species became dominant and undergrowth diminished to some species.
The important tree species included Acacia torti/is (Forsk.) Hayne. ; Acacia nilotica (L.) Wind.ex. Del. ; Leucaena /eucocephala (Lam.) de WItt. ; Acacia senega/ (L.) Willd.; Prosopis chi/ensis Stuntz..
3.2 Initial association:
Initial plant formed association and appeared to benefit with each other. These association included Calotropis procera (Ait) RBr. with nitrogen fixing Crotalaria burhia Buch-Ham. Besides this at a later stage the nitrogen fixing Tephrosia purpurea (L.) Pers. was largely predominant with other plant like Verbesina encelioides (Cav.) Benth. & Hook. Artemisia scoparia, Waldst; Sericostoma pauciflorum stock; Sida corditolia L.; Crota/aria burhia Buch.-Ham.; Boerhavia diffuse L. The biomass productivity ranged from 0.5 tonnes per ha. (Citrullus colocynthis), to 52 tonnes dry matter per he. per annum (Saccharum munja). A combination of these plant could be used to form a three tier system to colonize the wasteland and get productive biomass as an alternative model to the hydrocarbon yielding plants (6).
3.3 Some other association:
Boemavia diffuse, Citrullus colocynthis, Artemisia scoparia largely cover the ground throughout the year due. to their xerophytic adaptation make good association with these plants R. purpurea, V. encelioides, S. pauciflorum, C. bilmia, C. bonplandium, S. cordifolia, H. marifolium, P. angustifolia, P. corymbosa, E. hirta.
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Rural Energy Needs of India and Role of Women in Developing Alternative Sources of Energy: A Case Study In : Van Swaaij, Fjallstrom, Helm and Grassi (eds):. Biomass for energy, industry, and climate protection. Proceedings of the Second World Conference ETA-Florence, Rome Italy WIP-Munich , Germany pp 2510
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159. Kumar, A. A. Tewari (2004) Improving the Biofuel Utilization Efficiency in the Rural Villages by Modifying the Fire Stove ‘Chulha’ In : Van Swaaij, Fjallstrom, Helm and Grassi (eds):. Biomass for energy, industry, and climate protection. Proceedings of the Second World Conference ETA-Florence and WIP-Munich Pp 2544