SUSTAINABILITY OF POULTRY PRODUCTION USING THE EMERGY APPROACH: COMPARISON OF CONVENTIONAL AND ORGANIC REARING SYSTEMS

The organic production system is an important strategy, compatible with sustainable agriculture, avoiding the use of chemical compounds,limiting the intensity of production and providing controls along the entire chain of production. The aim of this study is to compare conventional and organic poultry production in terms of emergy analysis. The main differences in the two systems were the emergy cost for poultry feed and for cleaning/sanitization of the buildings between successive productive cycles. In both production systems the poultry feed represented more than 50% of the emergy flow. Regarding the agronomic phase, it was shown that almost all the organic crops, avoiding chemical fertilizers and pesticides, saved around 60% emergy. The emergetic costs for housing of the birds were very similar in both systems. Relating the emergy results with productive performance it is possible to show that, although the annual productive performance was much lower in organic than in conventional (206%), transformity of organic poultry was around 10% lower. Comparison of the organic poultry system with a conventional one from the viewpoint of sustainability showed that all the emergy-based indicators are in favour of the organic farming system with a higher efficiency in transforming the available inputs in the final product, a higher level of renewable inputs, a higher level of local inputs and a lower density of energy and matter flows

Sustainability assessment of wheat production using Emergy

Sustainability of crop production has to be given high priority when global biomass resources are limited. Here emergy evaluation is applied in order to assess sustainability of crop production exemplified by winter wheat. Emergy evaluation takes into account all inputs involved in a production system (i.e. renewable and non-renewable, local and imported) and transforms them into a common measure of direct and indirect solar energy requirement. The evaluation of winter wheat production is conducted by comparing conventional and organic management on two soil types using Danish reference conditions. The resource use efficiency of wheat production per kg biomass is higher using conventional management practices. This is due to high yield based on large use of non-renewable resources. The environmental loading ratio from organic management practices is about a third of the conventional implying that the organic management can be considered more sustainable

Evaluating renewable energy options for small islands using emergy methodology: A case study of coconut biodiesel in the Fiji Islands

The Pacific Island Countries including the Fiji Islands are heavily dependent on imported petroleum fuels for their energy needs. This is a major cause of environmental vulnerability as well as economic vulnerability due to high and volatile crude oil prices. A combination of Demand Side Management (DSM) to reduce energy consumption and optimize usage, and Renewable Energy Technologies (RET) to substitute fossil fuels can reduce their vulnerability. DSM consists of Smart Grids, Energy Efficiency and Storage, while RETs substitute fossil fuels by harnessing solar, wind, small hydro, biomass, geothermal and ocean energies. Comparative costs of electricity from RETs show that most of them are cheaper than the typical price of electricity in Pacific island countries. Nearly half of Fiji’s electricity is generated using petroleum fuels that can be substituted by biodiesel produced from locally grown coconuts. To evaluate the sustainability of coconut biodiesel, two different Environmental Accounting methods have been used: i) Emergy Analysis, and ii) Embodied Energy Analysis. Emergy Analysis is a holistic methodology that integrates all major inputs from the human economy and those coming ‘free’ from the environment, to evaluate complex systems. Emergy Performance Indicators for coconut biodiesel are: i) Emergy Yield Ratio is 1.32 indicating a low ability to exploit local resources efficiently; ii) Environmental Loading Ratio is 8.57 implying that biodiesel production causes significant environmental or ecosystem stress; and iii) Emergy Index of Sustainability is 0.15 indicating a low contribution to the economy per unit of environmental loading and a very high degree of environmental stress per unit of Emergy yield. Embodied Energy Analysis is a complimentary methodology that accounts for only the commercial energy (in kgs oil equivalent) required directly or indirectly to provide all the inputs (goods and services) for the entire biodiesel production process. Embodied Energy Performance Indicators are: i) Energy Return on Energy Invested is 2.47 which means that it is not worth the effort in energetic terms; and ii) Carbon dioxide Emissions during the production of coconut biodiesel is 1.38 kg CO2 per kg biodiesel showing that biodiesel is not climate neutral. This thesis adds to the growing body of knowledge that uses Emergy Analysis to evaluate sustainability of biofuels and other renewable energy options in a holistic manner. This is the first time in reported literature that Emergy Analysis has been used to determine the sustainability of coconut biodiesel. The Emergy and Embodied Energy performance indicators clearly show that coconut biodiesel is not a sustainable alternate source of energy for the Fiji Islands

Carbon footprint and emergy combination for eco-environmental assessment of cleaner heat production

cited By (since 1996)0; Article in PressInternational audienceThe aim of this paper is to study via environmental indicators to which extent, replacing fossil fuel with biomass for heating is an environmentally friendly solution. The environmental impact of using biomass depends mostly on the transportation process. Authors define the notion of maximum supply distance, beyond which biomass transportation becomes too environmentally intensive compared to a fossil fuel fired heating system. In this work a carbon footprint analysis and an emergy evaluation, has been chosen to study the substitution of wood for natural gas. The comparative study seeks to examine, via the two approaches, two heating systems: one is fired with wood, transported by trucks and the other one is fired with natural gas transported by pipelines. The results are expressed in terms of maximum supply distance of wood. In the emergy evaluation it represents the maximum supply distance permitting wood to be more emergy saving than natural gas. In the carbon footprint analysis, it represents the maximum supply distance permitting wood to be a carbon saving alternative to natural gas. Furthermore, the unification of carbon footprint and emergy evaluation permits to define, for both approaches, the minimum theoretical wood burner first law efficiency that allows, CO 2 or emergy to be saved, when there is no wood transport. In order to identify the impacts of the main parameters of the study a sensitivity analysis has been carried out. The case study investigated in this paper shows that there is a large gap between the results. The maximum supply distances calculated via carbon footprint and emergy evaluation are about 5000 km and 1000 km, respectively, anthe minimum theoretical wood burner efficiencies are about 5% and 54%, respectively. © 2012 Elsevier Ltd. All rights reserved

Environmental assessment of livestock systems with the Emergy methodology : Efficiency of extensive livestock systems in harsh environments

The livestock sector will need to provide meat and milk for a growing population, while at the same time limiting its environmental impacts. To meet this challenge, more and more studies are being conducted to identify the most efficient systems from an environmental perspective, especially those that use the fewest non-renewable resources in relation to their output.In 2006, an FAO report thus called attention not only to the environmental damage they cause, but also to the lack of efficiency of livestock systems, especially extensive systems in developing countries, whose level of food production remains low.Questioning this report, a recent study conducted by CIRAD in four different regions shows that extensive dairy systems in Mali can be more efficient than intensive systems in Reunion Island, and just as efficient as semi-intensive systems in western France. This result was obtained using the emergy methodology, which uses one type of unit to evaluate all the resources consumed to generate food or non-food products. This methodology takes into account the complex and multifunctional nature of livestock systems, especially extensive ones. Emergy could be a useful tool enabling decision-makers to develop livestock policies adapted to suit individual contexts, and to thereby meet the growing demand for livestock products