http://aoatools.aua.gr/pilotec/files/bibliography/Biofuels%20(alcohols%20and%20biodiesel)%20applications%20as%20fuels%20for%20internal-4026835713/Biofuels%20(alcohols%20and%20biodiesel)%20applications%20as%20fuels%20for%20internal.pdf

Biofuels (alcohols and biodiesel) applications as fuels for internal combustion engines

Effect of biodiesel fuels on diesel engine emissions

The relationship, on a global basis, between the amount of N fixed by chemical, biological or atmospheric processes entering the terrestrial biosphere, and the total emission of nitrous oxide (N2O), has been re-examined, us- ing known global atmospheric removal rates and concentra- tion growth of N2O as a proxy for overall emissions. For both the pre-industrial period and in recent times, after taking into account the large-scale changes in synthetic N fertiliser pro- duction, we find an overall conversion factor of 3-5% from newly fixed N to N 2O-N. We assume the same factor to be valid for biofuel production systems. It is covered only in part by the default conversion factor for "direct" emissions from agricultural crop lands (1%) estimated by IPCC (2006), and the default factors for the "indirect" emissions (follow- ing volatilization/deposition and leaching/runoff of N: 0.35- 0.45%) cited therein. However, as we show in the paper, when additional emissions included in the IPCC methodol- ogy, e.g. those from livestock production, are included, the total may not be inconsistent with that given by our "top- down" method. When the extra N2O emission from biofuel production is calculated in "CO2-equivalent" global warm- ing terms, and compared with the quasi-cooling effect of "saving" emissions of fossil fuel derived CO2, the outcome is that the production of commonly used biofuels, such as biodiesel from rapeseed and bioethanol from corn (maize), depending on N fertilizer uptake efficiency by the plants, can contribute as much or more to global warming by N2O emis- sions than cooling by fossil fuel savings. Crops with less N demand, such as grasses and woody coppice species, have more favourable climate impacts. This analysis only consid- ers the conversion of biomass to biofuel. It does not take into account the use of fossil fuel on the farms and for fertil- izer and pesticide production, but it also neglects the produc- tion of useful co-products. Both factors partially compensate each other. This needs to be analyzed in a full life cycle as- sessment.

/pdf/n-2-o-release-from-agro-biofuel-production-negates-global-3mj0225tkh.pdf

N 2 O release from agro-biofuel production negates global warming reduction by replacing fossil fuels

With increasing use of biomass for energy, questions arise about the validity of bioenergy as a means to reduce greenhouse gas emissions and dependence on fossil fuels. Life Cycle Assessment (LCA) is a methodology able to reveal these environmental and energy performances, but results may differ even for apparently similar bioenergy systems. Differences are due to several reasons: type and management of raw materials, conversion technologies, end-use technologies, system boundaries and reference energy system with which the bioenergy chain is compared. Based on review of published papers and elaboration of software data concerning greenhouse gas and energy balances of bioenergy, other renewable and conventional fossil systems, this paper discusses key issues in bioenergy system LCA. These issues have a strong influence on the final results but are often overlooked or mishandled in most of the studies available in literature. The article addresses the following aspects: recognition of the biomass carbon cycle, including carbon stock changes in biomass and soil over time; inclusion of nitrous oxide and methane emissions from agricultural activities; selection of the appropriate fossil reference system; homogeneity of the input parameters in Life Cycle Inventories; influence of the allocation procedure when multiple products are involved; future trends in bioenergy (i.e. second-generation biofuels and biorefineries). Because many key issues are site-specific, and many factors affect the outcome, it is not possible to give exact values for the amount of greenhouse gas emissions and fossil energy consumption saved by a certain bioenergy product, because too many uncertainties are involved. For these reasons, the results are here provided as a means of wide ranges. Despite this wide range of results, it has been possible to draw some important conclusions and devise recommendations concerning the existing bioenergy systems, and some emerging implications about the future deployment and trends of bioenergy products are pointed out.

Energy- and greenhouse gas-based LCA of biofuel and bioenergy systems: Key issues, ranges and recommendations

This work presents the evaluation of energy balance and GHG emissions in the production and use of fuel ethanol from cane in Brazil for 2005/2006 (for a sample of mills processing up to 100 million tons of sugarcane per year), and for a conservative scenario proposed for 2020. Fossil energy ratio was 9.3 for 2005/2006 and may reach 11.6 in 2020 with technologies already commercial. For anhydrous ethanol production the total GHG emission was 436 kg CO 2  eq m −3 ethanol for 2005/2006, decreasing to 345 kg CO 2  eq m −3 in the 2020 scenario. Avoided emissions depend on the final use: for E100 use in Brazil they were (in 2005/2006) 2181 kg CO 2  eq m −3 ethanol, and for E25 they were 2323 kg CO 2  eq m −3 ethanol (anhydrous). Both values would increase about 26% for the conditions assumed for 2020 mostly due to the large increase in sales of electricity surpluses. A sensitivity analysis has been performed (with 2005/2006 values) to investigate the impacts of the huge variation of some important parameters throughout Brazilian mills on the energy and emissions balance. The results have shown the high impact of cane productivity and ethanol yield variation on these balances (and the impacts of average cane transportation distances, level of soil cultivation, and some others) and of bagasse and electricity surpluses on GHG emissions avoidance.

/pdf/green-house-gases-emissions-in-the-production-and-use-of-1x19x6odh4.pdf

Green house gases emissions in the production and use of ethanol from sugarcane in Brazil: the 2005/2006 averages and a prediction for 2020.

A consortium of CONCAWE, EUCAR and the EU Commission's JRC carried out a Well-to-Wheels analysis of a wide range of\automotive fuels and powertrains. The study gives an assessment of the energy consumption and greenhouse gas emissions for each pathway. It also considers macroeconomic costs and the market potential of alternative fuels.

/pdf/well-to-wheels-analysis-of-future-automotive-fuels-and-26pskf80qn.pdf

Well-to-wheels analysis of future automotive fuels and powertrains in the european context

The tank, e.g. for liquefied fuel gas, comprises two lateral truncated cylinders (4,5) with vertical partitions (8,9) covering their rectangular side openings and joining their upper and lower edges. The edges of the truncated cylinders are also connected by curved rectangular panels (6,7) with convex surfaces facing outwards. The lateral cylinders and inner chamber can be of similar or different diameters, linked through holes (8a,8b) in the partitions. The cylinder and chamber assembly can be produced by extrusion, e.g. from aluminium, or by welding together pressed sheet metal sections.

Tank for pressurized fluid

Reservoir pour fluide sous pression, du type monte sur un vehicule
automobile pour contenir au moins un fluide sous pression, de forme
aplatie. Le reservoir comprend deux elements lateraux cylindriques 4 et 5
pourvus d'une ouverture rectangulaire sur toute leur longueur, les bords
superieur et inferieur de ladite ouverture etant paralleles a l'axe des
cylindres, et au moins une entretoise 8, 9, disposee dans une ouverture
rectangulaire et joignant les bords superieur et inferieur de ladite
ouverture, pour former un espace interieur clos en forme de cylindres
tronques juxtaposes 1, 2, 3.

Jean-Claude Griesemann

Papers

Well-to-wheels analysis of future automotive fuels and powertrains in the european context

Tank for pressurized fluid

Réservoir pour fluide sous pression