Emergy Exchange Ratio Research Articles

Assessing the sustainability of Brazilian oleaginous crops – possible raw material to produce biodiesel

The aim of this paper is to make an emergy assessment of oleaginous crops cultivated in Brazil, available to produce biodiesel, in order to determine which crop is the most sustainable. This study evaluates conventional agro-chemical farms that produce rapeseed (canola), oil palm, soybean, sunflower and cotton. Rapeseed (canola) crop uses 40.41% of renewable energy and it is the most sustainable conventional oil crop; on the other hand, it is not widely produced in Brazil, probably due to climate restrictions or low market demand. The oil palm emergy indicators are contradictory: its emergy exchange ratio (EER) value is the lower, showing the possibility of fair exchange, and the low transformity value indicates high efficiency; however, it also has low renewability (28.31%), indicating a high dependency on agro-chemicals (basically fertilizers). Oil palm is a potential energy source due to its high agricultural productivity, but appropriate management is necessary to increase its sustainability and reduce the use of non-renewable resources.

Emergy and economic evaluations of four fruit production systems on reclaimed wetlands surrounding the Pearl River Estuary, China

Emergy and economic methods were used to evaluate and compare a traditional tropical fruit cultivation system, for bananas, and three newly introduced fruit cultivation systems, for papaya, guava and wampee, on reclaimed wetlands of the Pearl River Estuary, China. The goal of this study was to apply ecological engineering principles to fruit production system designs to maximize total emergy benefits and sustainability. The evaluations considered input structure, production efficiency, environmental impacts, economic viability and sustainability. The market effects on emergy exchange were assessed both for purchasing the inputs to production and for selling the fruit. These market effects were also considered in the evaluation of sustainability by using the Emergy Index for Sustainable Development (EISD), which was evaluated with and without taking the change in natural capital (i.e., soil organic matter) into consideration. The results showed that all three of the newly introduced systems are much more sustainable than the traditional banana production system. The guava production system had the highest value of the Emergy Sustainability Index (ESI = 0.40). The high price of wampee gave it the highest economic yield/cost ratio (4.87) and EISD (0.73). Emergy and economic evaluations are complementary methods, with emergy analysis shedding more light on environmental support and impacts of the production systems not considered in the market value, and economic analysis focusing on the effects of markets on fruit production. The Emergy Exchange Ratio (EER) was proposed as a bridge between emergy and economic evaluations for specific systems and/or processes.

Emergy, nutrients balance, and economic assessment of soybean production and industrialization in Brazil

The aim of this paper is to evaluate the soybean production and industrial processing stages in Brazil using the emergy accounting methodology and economic cost and revenue estimation in order to assess the environmental and economic inputs to the soybean chain and to evaluate the amount of emergy and nutrients exported to European countries. The main findings of this work were that the agricultural stage uses the highest amount of resources. The emergy exchange ratio shows that farmers are delivering around six times more emergy in the soybean that is being sold than the emergy they are receiving with the money paid for it. Results demonstrate that producing raw soybean and soy meal for international markets makes Brazil lose a great amount of emergy and nutrients. Besides that, soybean production is nowadays providing low profitability to farmers because of low prices for soybean products and high prices for the chemicals used in soybean farming. Therefore, at present conditions, exporting soybean as a commodity results in low profit per unit of area.

Should a small combined heat and power plant (CHP) open to its regional power and heat networks? Integrated economic, energy, and emergy evaluation of optimization plans for Jiufa CHP

Abstract The development of industrial ecology has led company managers to increasingly consider their company's niche in the regional system, and to develop optimization plans. We used emergy-based, ecological-economic synthesis to evaluate two optimization plans for the Jiufa Combined Heat and Power (CHP) Plant, Shandong China. In addition, we performed economic input–output analysis and energy analysis on the system. The results showed that appropriately incorporating a firm with temporary extra productivity into its regional system will help maximize the total productivity and improve ecological-economic efficiency and benefits to society, even without technical optimization of the firm itself. In addition, developing a closer relationship between a company and its regional system will facilitate the development of new optimization opportunities. Small coal-based CHP plants have lower-energy efficiency, higher environmental loading, and lower sustainability than large fossil fuel and renewable energy-based systems. The emergy exchange ratio (EER) proved to be an important index for evaluating the vitality of highly developed ecological-economic systems.

Emergy and fair trade assessment of soybean production and processing in Brazil

PurposeThe purpose of this paper is to evaluate the soybean agricultural production system and the subsequent industrialization processes in order to assess the environmental sustainability of the soybean chain in Brazil and, also, to evaluate the amount emergy exchanged in the soybean trade.Design/methodology/approachThe emergy accounting methodology was used as analysis tool in this paper.FindingsThe main findings were, first, the distribution of emergy flows inputs according to soybean chain stages, being 94 percent used by the agricultural production system, 1 percent used by transport to industry, 4 percent used by crushing, and 1 percent for oil refining. Second, emergy indicators showed negative sustainability trends trough the soybean chain stages. Third, the emergy exchange ratio demonstrated that the soybean farmers are delivering around five times more emergy with the soybean sold that the emergy they are receiving with the money paid for it and, thereby, depleting its local natural resources.Practical implicationsThe agricultural production stage uses the highest amount of resources. Therefore, any improvement in the management of this stage will result in improvement of the whole soybean chain. In this context, the adoption of more sustainable soybean agricultural production systems becomes fundamental for the long‐term environmental sustainability of the soybean chain. Organic production models and agro‐forestry technologies should be used toward more sustainable soybean chain because it can help to decrease the dependence of the soybean production systems on external non renewable resources.Originality/valueEmergy accounting methodology provides a very comprehensive tool to complement and complete energy, economic and social information about the soybean chain in Brazil. The emergy exchange ratio provides information to access and enrich the discussion about soybean fair trade.

Emergy evaluation on the production, processing and export of coffee in Nicaragua

An emergy evaluation was conducted on the systems of coffee ( Coffea arabica L.) production, processing and export in Nicaragua in order to evaluate the environmental contributions to the tradeable products and thus enrich the discussion about fair trade. The emergy indices calculated were: transformities, % renewable, environmental loading ratio and emergy exchange ratio. The different emergy indices showed that coffee processing and industrialization are intensive activities, requiring large environmental support. The calculated transformities for coffee cherries, green coffee, roasted coffee and instant coffee were 3.35E+05, 1.77E+06, 3.64E+06 and 1.29E+07 sej/J, respectively. The emergy exchange ratio demonstrated that almost all purchasers benefit when buying green coffee from Nicaragua. The sales of roasted or instant coffee is of benefit for Nicaragua. This means that Nicaragua exports much more emergy in the green coffee sold than it imports in the money received for the coffee, thereby depleting its local natural resources. A fair price to pay for green coffee would range from 0.7 to 3 times the actual price paid now. Emergy analysis is a powerful tool in assessing the direct and indirect environmental requirements for a good or service and it is thereby able to evaluate trade in a much more comprehensive way than is usually done using standard economic measures. Inequity in international trade can be detected with this evaluation methodology. Therefore, we propose the use of emergy exchange ratio (EER), emdollars and emprice values as useful measures when trying to develop more sustainable and fair trade conditions.

Emergy assessment of integrated production systems of grains, pig and fish in small farms in the South Brazil

The present study uses emergy methodology to evaluate environmental aspects of integrated production systems of grains, pig and fish in small farms in the South region of Brazil. New emergy parameters that use partial renewability factor of each input were used to improve emergy accounting. These parameters were already applied to different case studies and are very appropriate for use in emergy assessment of integrated agricultural systems. The following indicators were calculated for the integrated production system of grains, pig and fish: transformity: 948,000 sej/J; renewability: 24%; emergy yield ratio: 1.44; emergy investment ratio: 2.28; environmental loading ratio: 3.13 and emergy exchange ratio: 6.8. These values were compared with results calculated for grains, pig and fish production subsystems working in a separated way. The results obtained signalize that an integrated system has better emergy efficiency, is more sustainable and is less stressful on the environment in comparison with separated production subsystems. The emergy indicators presented are discussed in the text and they will be useful in further work to assist the formulation of public policy, and also to recommend better management practices to farmers.

00/00848 Combined heat and power economic dispatch by improved ant colony search algorithm

The development of industrial ecology has led company managers to increasingly consider their company's niche in the regional system, and to develop optimization plans. We used emergy-based, ecological-economic synthesis to evaluate two optimization plans for the Jiufa Combined Heat and Power (CHP) Plant, Shandong China. In addition, we performed economic input–output analysis and energy analysis on the system. The results showed that appropriately incorporating a firm with temporary extra productivity into its regional system will help maximize the total productivity and improve ecological-economic efficiency and benefits to society, even without technical optimization of the firm itself. In addition, developing a closer relationship between a company and its regional system will facilitate the development of new optimization opportunities. Small coal-based CHP plants have lower-energy efficiency, higher environmental loading, and lower sustainability than large fossil fuel and renewable energy-based systems. The emergy exchange ratio (EER) proved to be an important index for evaluating the vitality of highly developed ecological-economic systems.