Emergy Investment Ratio Research Articles

EMERGY analysis for sustainability evaluation of the Baiyangdian wetland ecosystem in China

This study presents a quantitative and ecological benefit evaluation of the Baiyangdian wetland in China between the years 2000 and 2006. Methods of EMERGY analysis were applied to illustrate the wetland ecosystem, to evaluate the economic and environmental inputs and consequent yields, and to assess the sustainability of the Baiyangdian wetland. The indicators for the integrated ecological and economic system, such as EMERGY yield ratio (EYR) (7.51), EMERGY investment ratio (EIR) (4.52), environmental loading ratio (ELR) (2.92), EMERGY exchange ratio (0.41), and EMERGY sustainable indicator (ESI) (2.57) were calculated, compared, analyzed, and discussed. The non-renewable investment in Baiyangdian was greater than renewable investment, leading to the unsustainable development of the system. High EYR indicated that the Baiyangdian integrated system had created huge profits for its people, while ELR and ESI revealed that human behavior has been a heavy burden on the environment, and countermeasures should be taken by the Chinese government to relieve and resolve these problems. Potential management methods were also proposed in this paper.

Emergy evaluation of organic rice-duck mutualism system

Rice-duck mutualism is one form of ecological engineering which makes use of the symbiotic relationship between rice and ducks to more effectively utilize materials, reduce chemical fertilizer and pesticide inputs, increase product safety and overall productivity and decrease the pollutants discharged from rice-fields. This is becoming a popular mode for organic rice production in China and it can be used as one measure taken in the drainage area to assist in the ecological rehabilitation of lakes. This study applied the emergy evaluation method to analyze the resource use and environmental impact of organic rice-duck mutualism (mode 1) compared with the conventional wheat/rice rotation system (mode 2) in the same farm to evaluate its sustainability and ecological and economic benefits and provide suggestions for optimizing this system. The results showed that mode 1 produced greater emergy benefits, and had higher self-organization, lower environmental pressure and higher product safety. The net emergy yield ratio (EYR), feedback ratio of yield emergy (FYE) and emergy sustainable index (ESI) of mode 1 were 1.57 times, 14.10 times and 8.71 times those of mode 2, respectively, and the emergy index of product safety (PSI) was 0 in mode 1 and −0.66 in mode 2. The emergy investment ratio (EIR) and environmental loading ratio (ELR) were 40.1 and 18.3% of those of mode 2. The economic benefit of mode 1 was lower than mode 2. The economic output, gross income and net income of mode 1 were 15.7, 10.8 and 35.4% less than those of mode 2, respectively, but using Em$, the output, gross income and net income of mode 1 were 47.4, 161.2, 87.3% higher than mode 2. With the development of markets for organic foods, mode 1 has the potential to achieve better economic benefits.

Emergy analysis of eco-economic systems of Hunan Province

A quantitative analysis and an evaluation of the eco-economic system of Hunan Province were performed on the basis of emergy theory. The results show that in 2004, total emergy used in Hunan Province is 2.23×1023 sej, including renewable emergy flow (3.52×1022 sej) and non-renewable emergy flow (2.08×1023 sej). Emergy value in money flow is 6.21×1023 sej, including import-emergy flow (1.07×1022 sej) and export-emergy flow (3.09×1022 sej). Total waste emergy is 4.11×1021 sej, 1.84% of total emergy of the province. Ratios of self-support emergy and net emergy yield are 95.20% and 23.72, respectively. Net-export emergy, per-capita emergy, emergy density, emergy/dollar ratio and emergy investment ratio are 2.02×1022 sej, 3.32×1015 sej, 1.05×1012sej·m-2, 3.33×1012 sej·＄-1 and 4.36% respectively. Ratio of electric power to total emergy is 12.60%, environmental loading ratio is 5.34, carrying capacity of renewable energy is 1 056.90×104 persons and total carrying capacity is 8 455.18×104 persons. On the basis of the results, vital suggestions are advanced for the sustainable development of eco-economic system in Hunan Province.

Specific emergy of cement and concrete: An energy-based appraisal of building materials and their transport

Abstract Use and production of building materials, such as cement and concrete, is a major cause of global ecological problems with special reference to the overexploitation of non-renewable natural resources due to high temperature production processes, fossil fuels combustion, extraction of raw materials and non-recycling. In this paper, an environmental accounting method was applied to the production of cement and concrete in order to evaluate its dependence on natural resources even non-renewable and heavily relied on external inflows. The main steps of the production process (1) cement production, (2) transport of materials and (3) concrete mixing, were assessed by the emergy analysis (spelled with an “m”). This was performed to measure the amount of environmental resource use in terms of equivalent solar energy, extending the energy hierarchy principle to building materials. The resulting unit emergy values of cement and concrete were compared with previous emergy assessments in order to highlight how emergy analysis is sensitive to local context and reference system's boundaries. An Emergy Investment Ratio (EIR) was assessed and presented as a synthetic indicator of sustainability. Results showed a high dependence of cement and concrete production on external resource flows. Furthermore, the high value of EIR suggested a weak competitive capacity due to a high sensitivity to external instabilities.

Emergy analysis of cropping–grazing system in Inner Mongolia Autonomous Region, China

An ecological energetic evaluation is presented in this paper as a complement to economic account for the cropping–grazing system in the Inner Mongolia Autonomous Region in China in the year 2000. Based on Odum's well-known concept of emergy in terms of embodied solar energy as a unified measure for environmental resources, human or animal labors and industrial products, a systems diagram is developed for the crop and livestock productions with arms and sub-arms for free renewable natural resource input, purchased economic investment, yields of and interactive fluxes between the cropping and grazing sub-industries. In addition to conventional systems indices of the emergy yield ratio (EYR), emergy investment ratio (EIR), environmental load ratio (ELR) and environmental sustainability index (ESI) introduced for congregated systems ecological assessment with essential implication for sustainability, new indicators of soil emergy cost (SEC), self-support intensity (SSI) and self-support orientation (SSO) are defined to characterize the desertification and internal recycling associated with the special agricultural system. Extensive emergy accounting is made for the cropping-grazing system as a whole as well as for the cropping and grazing subsystems. The overall cropping–grazing system is shown with outstanding production competence compared with agricultural systems in some other provinces and the national average in China, though confronted with severe desertification associated with soil loss. The production of crops has higher emergy density and yield rate per unit area as well as higher rate of soil loss than grazing system. The soil emergy cost defined as the soil loss emergy divided by the yield emergy is estimated to be of the same value for both of the subsystems, but the grazing activity is with less extraction intensity, leaving rangeland to rest and rehabilitate. Suggestions with regard to the local sustainability and national ecological security in northern China are explored for land-use policy making.

Dynamic emergy accounting for assessing the environmental benefits of subtropical wetland stormwater management systems

An eco-hydrological model of a subtropical urbanizing watershed in south Florida, USA was developed to simulate solar emergy using H.T. Odum's energy systems language as programmed in an iconographic simulation software (i.e., Extend ®) to provide dynamic valuation of a wetland stormwater management system (WSMS). The solar emergy (i.e., ultimate amount of solar energy required to produce another form of energy) and emdollar (EM$, value an energy flow contributes to an economy based on its proportion of total emergy flow) values of watershed transpiration (a measure of productivity), surface discharge and change in landscape water storage were quantified for various ratios of wetland to upland areas, valuing wetlands in EM$ ha −1 y −1. Simulation results indicated that integrating a WSMS into the watershed increased landscape productivity, decreased surface discharge and increased surface water storage. The eco-hydrological value of watershed productivity was 367 EM$ ha −1 y −1 when 10% of the watershed was wetland, which was an increase of 65 EM$ ha −1 y −1 (based on Florida's emergy-to-dollar ratio in 1985, 2 × 10 12 sej $ −1). The annual contribution of this extra ecological productivity to public welfare was 12 million EM$, which was estimated from the product of eco-hydrological value and local emergy investment ratio of south Dade County (18:1). Average emdollar value of water saved per unit of wetland was 343 EM$ ha −1 y −1. Dynamic emergy accounting provided distributions of solar transformities of hydrologic variables as opposed to more commonly used point estimates. Our work advances the temporal dynamic principles of emergy accounting by demonstrating how solar emergy may be continuously tracked through an ecosystem to estimate the value of nature's life-support services.

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.

Emergy analysis of the Oak Openings region

This study examines an alternative to market valuation for determining worth through a case study of the Oak Openings region in Northwest Ohio, USA. Emergy analysis methods are explained, illustrated and used to tabulate environmental, cultural and economic subsystems of the region. The emergy yield ratio for the region at 1.57 suggests sustainability but is less than the findings of other researchers looking at environment-dominated systems. Its loading ratio at 15.2 indicates very high levels of stress—undeveloped and developing areas in the US typically exhibit loading ratios of between 1 and 5. The region’s emergy investment ratio at 2.3 is much more efficient than some urban areas with investment ratios as high as 26; but it still suggests less efficiency and greater reliance upon non-renewable resources than other studies of natural systems where investment ratios are less than one. The inclusion of cultural emergy analysis, which is still in its infancy, complicates the findings here reported. Questions regarding cultural emergy are considered.

Emergy-based indices and ratios to evaluate sustainability: monitoring economies and technology toward environmentally sound innovation

This paper provides a reference set of indices based on emergy, for the evaluation of ecotechnological processes and whole economies. Indices of emergy yield ratio (EYR), environmental loading ratio (ELR), and emergy investment ratio (EIR), among others, are stressed, and a new index the emergy sustainability index (ESI) is defined. The emergy indices for a given system are shown to be functions of renewable, nonrenewable and purchased emergy inflows. Indices are given for several ecological engineering activities including oil spill restoration, land reclamation and wastewater recycle through wetlands, several production systems, and several national economies to demonstrate their usefulness. Ecological engineering involves both natural and engineered systems and the flows of renewable and nonrenewable energy, the appropriate amounts of which are important to determine if they are to result in sustainable use of resources. The sustainability index can be used to evaluate appropriate nonrenewable investments in eco-technology to maximize their performance. Sustainability of economies is shown to be a function of the net yield of the economy and its `load' on the environment. The trends of these indices can be monitored over time and provide useful information about the dynamics of economic systems within the carrying capacity of the environment in which they develop. When a particular sector or production process is focused on, instead of a national economy, emergy based indices can provide insights into the thermodynamic efficiency of the process, the quality of its output, and the interaction between the process and its surrounding environment.