Bibliographic review

Emergia: generalities, notes, and examples of utility, as a tool to evaluate sustainability

Bruna Elena Torres-Verzagas^{1  *} 

Ángel Leyva-Galán² 

Pedro Pablo Del Pozo-Rodríguez³ 

¹Dirección de Protección Fitosanitaria de Matanzas. Carretera central km 111 Gelpi Matanzas, Cuba

²Instituto Nacional de Ciencias Agrícolas (INCA), carretera San José-Tapaste, km 3½, Gaveta Postal 1, San José de las Lajas, Mayabeque, Cuba. CP 32 700

³Universidad Agraria de La Habana “Fructuoso Rodríguez Pérez”, carretera a Tapaste y Autopista Nacional. San José de las Lajas. Mayabeque, Cuba. CP 32 700

ABSTRACT

Throughout its history man has used emergia as a useful tool to evaluate the efficiency of productive systems even for a long time, and because of the lack of knowledge of the advantages of using the emergia analysis, he has not been given, greater utilization. The advances of science, have allowed deepening in the studies on the implementation of Methodology Emergent Synthesis. Every year a considerable number of different types of energy are in different production processes generated, but only a certain part is recognized and accounted, since most are lost because of the ignorance of the benefit it represents, the power to use it, on put it at the service of ecosystem. Faced with this problem, we try to demonstrate the importance of the study, and the implementation of methodologies, leading to a closer approach to sustainability. In the present bibliographic review, an approach is made on the subject of Emergence. In addition, it summarizes aspects related to the nomenclature to be used, as well as indicators and indexes more common to evaluate. Finally, some examples are presented, in which the use of this methodology has been, successful, while reflecting on the importance of the subject future research.

Key words: methodology; efficiency; emergetic analysis; ecosystem; sustainability

INTRODUCTION

At the beginning of the last century, man began to develop a whole new energy base, on the use of coal, oil, and other sources of energy, to complement solar energy. Large amounts of energy, whose accumulation was the result of hundreds of millions of hectares of solar energy, suddenly became sources of energy available to man ¹. After more than five decades of work in ecology, and general systems theory, this author has proposed a biophysical method, based on the analysis of energy with memory, called Emergia, to correctly carry out the accounting of services, which provide ecosystems for free.

The first formal statement of what would later be called emerged, occurred through the following reflection, ''La energy is measured in calories, btu, kWh, and other incontrovertible units, but energy has a scale of quality, which is not captured by these measures. The ability to develop work for man depends on the quality and quantity of energy, and it is measured by the amount of energy of a lower quality needed, to develop energy of a higher degree of quality. The energy scale is, since the diluted solar power for primary production, coal, coal oil, electricity, efforts to processing and human computing'' ². Between 1986 and today, the emergent methodology has been developed, while the research community was expanding and new applications of the methodology were presented, in combined man-nature systems, which has become, in turn, new challenges. The maturity of the methodology has resulted in more rigorous conceptual definitions and nomenclatures, as well as a refinement in the methods of calculating the transformations.

The emergetic analysis proposed by Howard T. Odum constitutes a valid methodology for the integral and systemic evaluation of ecosystems, which estimates the values of emergencies incorporated in environmental products, processes and services, as well as the impact of activities Anthropic in ecosystems ^3-7. Countries in Latin America and the world, have achieved satisfactory results when using the emergent analysis, as a way to solve problems in which the natural and socioeconomic elements intermingle, for the integral and systemic evaluation of the ecosystems being Brazil, one of the more faithful exponents of these studies.

At present, the use of this methodology is of transcendent importance; however, research in Cuba is still incipient, since there is only the accumulated experience of some authors ⁸, for the undertaking of works of similar magnitude.

General and conceptualization

The terms have been handled indistinctly: Emerging, Methodology and Emergetics, Emerging Synthesis, Emerging Analysis or Emerging Synthesis Methodology. The concept itself has generated a multitude of controversies, within many communities there are academics including Ecology, Thermodynamics and Economics ^9-14. To avoid confusion with other forms of analysis and rigorously define the concepts, a completely energetic nomenclature has been developed which defines the terms, symbology, abbreviations, units, indicators and indices, used in the emergetic evaluations.

Emergia is a tool, which can be used to compare the work of nature with that of humans, on a fair and equitable basis ¹⁵. This author asserts, which is the sum of all the energy in one way, necessary to develop an energy flow in another way, in a given period of time ¹⁵; in other words , it is the useful energy in a certain way, used directly or indirectly to generate a certain product or service . Its unit is the energy emjoule, and when used it can be put on a common basis, sunlight, fuels, electricity, and human services, expressing them in solar energy emjoules, which each of them requires to be produced. There are other definitions but in general, the emergence takes into account different forms of energy and resources (eg sunlight, water, fossil fuels, and minerals, among others). Each of these forms of energy is produced through processes of transformation in nature and has a certain capacity to perform work, both in ecological and human systems. The recognition of these differences in "quality" is a key concept in the Emergia methodology.

Expressing the value of products emerging units is possible compares different types using transformity ^16,17. Emergia expresses the cost of a process or product in equivalent of solar energy, considering it is our source of energy end.

The emergia synthesis methodology evaluates resources and services in ecological and economic systems, on a common energy basis and quantifies direct and indirect environmental work, to generate a resource or a service. Some authors ^(18,19, named so this methodology, being an approach that tries the understanding of the whole of a system and its relationship to surrounding systems, instead of dissection and fragmentation is carried out in an analysis. Other authors have been able to verify that the emergent synthesis gives an understandable image of the environmental contributions to a product or service ²⁰, because in the same unit, it is able to integrate the flow of matter, energy, and capital ¹⁸.

Solar emergia, is the solar energy consumed directly or indirectly, to make a product or perform a service and its unit is the solar emjoule. To evaluate all the flows and storage on a common reference, solar emergia ^21,22 is used , which has been defined previously. The flow of energy that supports each source of importance is expressed in solar emergency units.

The evaluation in emergetic terms of the use of inputs and economic resources is relatively easy, although in the case of natural resources; a greater effort is required to obtain the values of the flows of matter and energy and their respective conversion factors, to Emerging flows. In emergetic analysis, the environmental, social and economic variables so n including s and the index s, so n calculated s com or tool s of comparison n couple to different s systems ²³⁾ . Despite its advantages, the emergetic analysis has received some criticism, particularly from economists, for ignoring the human valuation of goods and services ²⁴⁾ ; however, quantification of emerging, aims to provide an egocentric value or the products and ecological process ¹⁵.

The theoretical and conceptual bases of the emergent methodology are found in thermodynamics, systems ecology ²⁵⁾ and general systems theory ²⁶. There are two key publications, which serve to understand the history of this theory during its first 30 years, the book by HT Odum “Environmental Accounting” ¹⁸⁾ and the volume edited by C.A,S Hall entitled “ Máximum Power” ²⁷.

At the beginning of the 50s, Odum observed the quality of the energy, based on the results of its research and simulation models, of ecosystems and nature at ^28-30, among others, in which it manages different forms of energy at different scales. His research on flows of energy in ecosystems and differences in working potential of sunlight, the freshwater currents, winds, ocean currents, and even fossil fuels have highlighted.When two or more energy sources direct a system, these cannot be added without first converting them to a common measure, which takes into account not only their quantity but also their quality. This reasoning led to the concept of “energy of a certain type” with the name “cost and energy” ³¹.

Summary of emergia: point of departure as a new field study

The point of departure for the synthesis of emerged as a new field of study, lies in that compare different types of energy, using factors of conversion that show the amount of equivalent energy types. In based of the Principle of "Maximum flow of energy" ³², it is proposed a new law of thermodynamics, in base of the principle of maximum empower. It is the speed of emergia flow in the manner analogous to power, which is in turn the speed of energy variation ^1,22.

Emergetic language

It is very important knowledge and mastery of the language and nomenclature, referred to the subject under study. In this effort, it must adhere to the symbols used by Odum, for which reference is made to article entitled, ''Emergy (with mesmo''m'') e o sistema embalagem idéias para modelagem'' ³³, in which main symbols diagram energy are visualized (Figure 1) ^18,34,35, although they have been used since 1965.

Figure 1 Main symbols of energy diagram ^18,34,35  

Once the knowledge about this language has been acquired, this tool can be used in different research areas.

To transform the flows of matter, energy, and the capital, in emergia expressed in one common currency (as the solar emjoules), will need information further. This additional factor is the transformity, which is defined as the emerging of one kind required to make one unit energy of another type ³⁶.

Utility of emergetic methodology as a tool to evaluate sustainability

Emerging synthesis has proved to be a valuable tool, to evaluate the performance of agricultural ecosystems, in terms of resource consumption during the productive process and the resulting efficiency ¹⁴.

From the recorded variations of the emergent indicators over time, trends on the functioning of ecosystems can be illustrated. Studies based on emergent synthesis have been carried out, which explore from a historical perspective the consumption of ecological and economic goods of agricultural ecosystems ³⁷.

For the use and analysis of this methodology the following steps are followed: (a) preparation of the systemic diagram; (b) preparation of the emergent evaluation table; (c) calculation of the emergent indexes; (d) interpretation of the results ¹⁸.

The diagram and energy flows can be useful for a better understanding of the laws of thermodynamics. Its purpose is to develop a critical inventory of the processes, reserves and flows that are important “drivers” of the system and are therefore necessary for evaluation. Any portion of the universe can be considered as a system, or an entity formed by interdependent units or components that interact with each other and function as an integrated entity, using the symbols of the general theory of systems ³⁸.

The diagram should always be referred to a higher system ("less detail-greater detail" approximation), since it allows a clearer picture of the organization of the system and once prepared, the energy calculation of each flow can be performed, to find its emergent equivalent.

The data of the flows that enter to the limits of the system, are in energetic units (joules) or specific (grams) generally annual (j/year or g/year). These units are multiplied by their respective transformation, to obtain their emergence and subsequently added, to obtain the total emergence and calculate the respective emergent indexes ³⁹.

The goal of building the systemic diagram, is visually represent the studied system, with all inputs (be they of the resources of nature or economics), internal flows, losses and outputs (in the form of energy, products, money, etc.) This represents as real as possible the system studied, expressed all its complexity, and it is the basis for the emergetic analysis of the systems studied, for which is used the symbols proposed by Odum ¹⁸.

For the elaboration of this diagram or quantitative model of the systems, the resources of nature (I), renewable (R) and non-renewable resources (N), the resources of the economy (F), materials are taken into account (M) and services (S), in Figure 2 is shown the model diagram used.

Figure 2 Model of a Systemic Diagram 

It is possible to present the systemic diagram of the emergia flow of different system from them is analyzed the qualitative form, the totality of emergia sources that enter, the ones that go out the internal flow that converge in them, by relying these of nature resources. It is important to achieve a good use of biological nitrogen fixation, carbon sequestration, and take into account the mobilization of minerals in the system, being able to have a wide diversity and amount of biota in the soil, as well as possess the amount of plant species capable of storing nature's carbon (CO) resource, through photosynthesis.

That is why the inclusion of trees and shrubs in agricultural ecosystems is a valid and necessary option, which has taken interest and importance for the production and protection of agroecosystems in the tropics especially in Latin American countries, whose results are they sustain in the increase of the productivity and quality of life of the producers ⁸.

The second step refers to the preparation of an energy evaluation table (Table 1) and for this, the flows of resources, labor and energy are taken into account, based on the diagram previously prepared. The data on the inflows that cross the boundaries become emergent units and then add up, to obtain the total emergence that directs the system. These flows per unit of time (usually per year), are presented in a table as separate elements, making the calculations of the components (solar energy, tides, electricity, rain, etc.) with the respective amount of emergia.

Table 1 Model of an emergetic table 

Note	Contributions	Numerical value	Transformation unit	Energy flows

The Emtable software is also used for estimating the indices, which has different modules (spreadsheets), in which they enter the basic information for the calculations, and these would be the ones set out below:

• General information of the productive unit studied

• Renewable and non-renewable resources of nature

• Materials of the economy, with their respective renewables

• Financing

• Infrastructure

• Economy services, whether family or contracted, with their respective renewals.

• Products of the crops, either for sale or for self-supply

• Products of the Permanent Preservation and Legal Reserve Area³, goods and services generated in the two areas

• By-products, unwanted outputs of the systems

• Results: where the return calculates the emergency flows

• Graphics

As for the emergetic indexes, these are calculated from the energy flows and are used to evaluate the degree of use of the resources in the systems. Among the most used indexes and their respective equations are: Transformicity and Renewability.

The Transformity, is the amount of emerging introduced per unit of useful energy generated and determined by the equation: $\text{Tr}=\text{Y}/\text{Ep}$ , expressed in seJ/J.

The transformation of sunlight absorbed by the Earth is 1.0 by definition.

Renewability is the relationship between renewable energy and total emergency use, where the percentage of total emergency used that is renewable is expressed. This index responds to the equation, $\text{\% Ren}=100\times \left(\text{R}/\text{Y}\right)$ , where: [R] Renewable intakes and [Y] Total Emergia. The greater % of Renewability, greater sustainability of the system, which shows a lower dependence on external inputs.

In other indices it can mention, reason of emergetic yield, reason of emergetic inversion, reason of environmental charge and reason emergetic exchange.

Examples that demonstrate the utility of employment method of emergetic analysis

Currently, some countries use this tool to assess the sustainability of their systems with very good results.

In Colombia, models were investigated, which allow an environmental accounting, which integrates natural and urban ecosystems, being in the emergent synthesis, the most novel proposal, based on the concepts of thermodynamics ³⁹.

Experience showed that it is possible to assess urban systems, with the method of emergent synthesis, allowing to differentiate between environmental economy and ecological economy, giving value to natural resources together with the entire economic and social system, in a single accounting and thus direct the areas of sustainability, with the calculation of emergent indexes for decision making in public policies.

In Argentina, the experience consisted of a historical analysis of an agricultural ecosystem, with the objective of evaluating the performance pattern of the different alternatives. The Emergetic Sustainability Indicator (ESI), which is an aggregate measure of the potential contribution to the economic system (EYR) per unit of pressure exerted on the local system (ELR), is calculated using the formula. $\left(\text{ESI}\right):=\text{EYR}/\text{ELR}$ revealed that the alternatives made net contributions through the production generated by the crops, without producing great effects on the environment. In this way, the study carried out allowed us to know how the biophysical and economic performance and performance of the agricultural ecosystem was modified, over a certain period of years. From the recorded variations of the emerging indicators over time, trends on ecosystem functioning could be illustrated.

In the case of Brazil ⁸, an assessment is made of the degree of resource utilization and sustainability, in two production systems. The indices used were: Transformity, Renewability, and Reason for Emerging Performance, Reason for Emerging Investment, Reason for Environmental Burden and Reason for Emerging Exchange.

These examples demonstrate that the use of the methodology of emergent analysis turned out to be an effective tool to evaluate sustainability in agroecosystems.

CONCLUSIONS

• All foregoing exposed, corroborates the importance of using methodological tools, that favor closer to sustainable development.

• Is undeniable that many countries are already using the of emergetic synthesis methodology, with the end of the proposal implementation to close to the reality of a system of natural resources to an integrated management.

• For the author's consideration, the implementation in Cuba of the emergent analysis methodology would be very useful, as a tool to account for the use of resources and evaluate sustainability in agroecosystems, specifically those that are inserted in the cooperative and peasant sector, which are more feasible to handle by representing small and medium enterprises.

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Received: January 11, 2018; Accepted: March 26, 2019

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