Energy returned on energy invested | Wikipedia audio article
In. Energy, economics, and ecological. Energetics, energy, returned on energy invested, er, Oei or arrow a or energy, return on investment. EROI, is the ratio of the amount of usable energy. The exergy delivered. From a particular energy, resource to the amount of exergy used to obtain that energy resource arithmetic. Li the ero AI can be defined, as e. Oh. Oh. II. I. Equals energy. Delivered. Energy. Required, to deliver that energy. Display. Style ero AI equals, track hbox energy, delivered, hbox, energy, required to deliver that energy. When. The ero AI of a source of energy is less than or equal to, one that energy source becomes a net energy sing. And can. No longer be used as a source of energy but, depending, on the system might be useful for energy, storage for, example a battery a related. Measure energy stored, on energy invested ESO, AI is used to analyze storage. Systems, to be considered, viable as a prominent fuel, or energy source, of fuel or energy must, have an ER Oei ratio, of at least three to one. Topic. History. The, energy, analysis, field of study is credited, with being popularized. By charles a.s hall a systems, ecology and biophysical. Economics, professor, at the state university. Of new york, hall. Applied, the biological. Methodology. Developed, at an ecosystems. Marine Biological Laboratory. And, then adapted, that method to research human industrial. Civilization. The. Concept, would have its greatest exposure, in 1984. With a paper by hall that appeared on the cover of the journal Science. Topic. Application. To various, technologies. Topic. Photovoltaic. The, issue is still subject, of numerous studies, and prompting, academic, argument. That's. Mainly because the, energy. Invested. Critically. Depends, on technology. Methodology. And system, boundary, assumptions. Resulting. In a range from a maximum, of 2,000, kilowatt hours, per square meter of module, area down to a minimum of 300, kilowatt, hours per square meter, with a median, value of. 585. Kilowatt. Hours per square meter, according, to a meta study regarding. Output, it obviously, depends, on the local insulation, not just the system itself so, assumptions, have to be made. Some. Studies see below include, in their analysis, that photovoltaic, produce. Electricity. While the invested, energy may be lower grade primary, energy a. 2015. Review, in renewable, and sustainable energy.
Reviews. Assessed the energy payback time and E ROI of a variety of PV, module, technologies. In. This study which, uses an insulation, of. 1700. Per kilowatt, hours per square meter per year in the system, lifetime, of 30 years mean harmonized d ROI is between, eight point seven and thirty four point two were found, mean. Harmonized, energy, payback time varied. From one point O to four point one years. Topic. Wind, turbines. The, EROI, of wind turbines, depends. On invested, energy in the turbine produced, energy and lifespan, of a turbine, in, the, scientific. Literature, ero eyes normally, vary between 20, and 50. Topic. Oil sands. Because. Much of the energy required for producing, oil from oil sands bitumen comes, from low value fractions, separated. Out by the upgrading, process there, are two ways to calculate ero, AI the, higher value, given by considering. Only the external, energy inputs, and the lower by considering, all energy, inputs including. Self-generated. One. Study found that in 1970. Oil sands, net energy Returns was about 1.0. But by 2010. Had increased, to about five, point two three. You. Topic. Non, man-made, energy, inputs. The, natural, or primary, energy sources, are not included, in the calculation, of energy invested, only the human applied, sources. For. Example, in the case of biofuels, the solar insolation, driving, photosynthesis. Is not included, and the energy used in the stellar synthesis, of fissile elements, is not included. For nuclear, fission, the. Energy, returned, includes, only human usable, energy and not waste such as waste heat. Nevertheless. Heat. Of any form can be counted, where it is actually used for heating, however. The use of waste heat in district, heating and water desalination, in cogeneration, plants. Is rare and in practice, it is often excluded, in EROI analysis. Of energy sources. Topic. Competing. Methodology. In a 2010, paper by Murphy and Hall the advised extended. Ext. Boundary. Protocol. For all future research on ero I was, detailed, in order. To produce what, they consider, a more realistic assessment. And generate, greater consistency, in, comparisons. Than what hall and others view as the weak, points. In a, competing methodology. In more, recent years, however a source of continued, controversy. Is the creation of a different methodology endorsed. By certain, members of the IEA which, for example most, notably, in the case of photovoltaic solar, panels, controversially. Generates, more favorable, values in the case of photovoltaic solar. Panels the IEA method, tends to focus on the energy used, in the factory process. Alone in. 2016. Hall observed, that much of the published work in this field is produced by advocates, or persons, with a connection to business interests, among the competing, technologies, and that government agencies had, not yet provided adequate, funding for rigorous, analysis, by more neutral, observers. Topic. Relationship. To net energy gain. Er, OE iron, net energy gain, measure, the same quality, of an energy source or sink in numerically.
Different Ways, net. Energy describes. The amounts, while er Oei measures, the ratio or efficiency, of the process, they. Are related, simply, by, gross. Energy yield. Divided. By. Energy. Expended. Equals. Oh II. I. Display. Style, hbox, gross, energy yield div hbox, energy, expanded, equals, ero e i o. Net. Energy. Divided. By energy. Expanded. Plus. 1. Equals. E, ah. Oh II. I. Display. Style hbox, net, energy div, hbox, energy, expended, plus one equals, ero AI. For. Example, given, a process, with an ero AI of five expending. One unit of energy yields. A net energy gain of four units, the. Break-even, point happens. With an ero AI of 1 or a net energy gain of zero the. Time to reach this breakeven. Point is called energy payback period. Epp, or energy, payback time, EP, bTW. Topic. Economic. Influence. Although. Many qualities, of an energy source matter for, example, oil is energy dense and transportable, while wind is variable, when the er Oei of the main sources of energy for an economy, fall that energy becomes more difficult to obtain and, its relative, price may increase, in. Regard. To fossil, fuels when oil was originally, discovered it took on average one barrel of oil to find extract, and process about, 100, barrels of oil the. Ratio, for discovery, of fossil, fuels in the United, States has, declined steadily over the last century, from about 1,000. To one in 1919. To only 5 to 1 in the 2010s, since the invention of Agriculture humans, have increasingly, used exogenous, sources. Of energy to multiply, human, muscle power. Some. Historians, have attributed this largely, to more easily exploited, ie higher ER Oei energy. Sources which is related, to the concept of energy slaves. Thomas. Homer Dixon argues, that a falling, er Oei in the later Roman Empire, was one of the reasons, for the collapse of, the Western Empire in the 5th century CE, in. The. Upside, of down, he. Suggests, that er Oei analysis. Provides, a basis, for the analysis, of the rise and fall of civilizations. Looking. At the maximum extent of the Roman Empire 60, million and its technological base, the agrarian base, of Rome was about 1/12, per hectare, for wheat and 127. For alfalfa, giving a 1 to 2.7. Production. For oxen, one. Can then use this to calculate the, population of, the Roman Empire required, at its height on the basis of about. 2,500. To 3,000, calories per, day per person it. Comes, out roughly, equal to the area of food production at its height, but. Ecological. Damage deforestation. Soil. Fertility, lost particularly. In southern, Spain southern, Italy Sicily and especially North, Africa, saw a collapse, in the system beginning in the 2nd century as, er Oei began, to fall it. Bottomed in 1084. When Rome's population. Which had peaked under Trajan at 1.5, mm was only 15,000. Evidence. Also fits, the cycle of Mayan and Cambodian, collapse to Joseph. Tainter suggests. That diminishing, returns of the er Oei is a chief cause of the collapse of complex societies. Which has been suggested as caused by peak word in early societies. Falling. Er Oei due to, depletion of high-quality fossil. Fuel resources also, poses a difficult challenge, for industrial, economies, and could potentially, lead to declining, economic. Output and challenge a concept, which, is very recent when considered, from a historical, perspective of, perpetual, economic, growth tim garrett linked cro AI and inflation, directly, based on a thermodynamic. Analysis, that links current world energy, consumption, watts, to a historical, accumulation.
Of Inflation, adjusted, global, wealth u.s. dollars known as the garrett relation, this. Economic, growth model, indicates, that globally, ROI is the inverse of global inflation over a given time interval. Because. The model aggregate, supply chains, globally, locally, are Oei is outside, its scope. Topic. Criticism. Of ER Oei. Er, Oei is calculated. By dividing the, energy, output by the energy, input. Measuring. Total energy, output is, often easy especially. In the case for an electrical, output, where some appropriate electricity. Meter can be used, however. Researchers. Disagree on how to determine energy, input accurately, and therefore, arrive at different numbers, for the same source of energy how, deep should the probing in the supply chain of the tools being used to generate energy go. For. Example, if steel is being used to drill for oil or construct, a nuclear, power plant should, the energy input of the steel be taken into account, should. The energy input into building the factory being, used to construct, the steel be taken into account and, amortized. Should. The energy input of the Rhodes which he used to ferry the goods be taken into account, what. About the energy used to cook the steel workers breakfasts. These, are complex questions, evading simple answers, a full, accounting, would require considerations. Of opportunity, costs, and comparing, total, energy expenditures. In the presence and absence of, this economic activity. However. When, comparing two, energy, sources a standard, practice for the supply chain energy, input can be adopted, for. Example, consider, the steel but don't consider the energy invested, in factories, deeper, than the first level in the supply chain it. Is in part for these fully encompassed, systems reasons, that in the conclusions, of murphy and halls paper in 2010, EROI, of five by their extended methodology. Is considered, necessary to, reach the minimum threshold of sustainability. While a value, of 12 to 13 by hall's methodology. Is considered, the minimum value, necessary, for technological. Progress in, a society supporting. High art Richards, and watt proposed an energy yield ratio for photovoltaic systems. As an alternative, to ER Oei which they refer to as energy return factor, the. Difference is that it uses the design lifetime of the system, which is known in advance rather. Than the actual lifetime. This. Also means that it can be adapted to multi-component, systems. Where the components. Have diff and lifetimes, another, issue with EROI that many studies attempt to tackle is that the energy returned, can be in different forms, and these forms, can have different, utility. For. Example, electricity. Can be converted more efficiently, than thermal energy, into motion due to electricity's. Lower entropy, in. Addition. The form of energy of the input can be completely, different from the output, for. Example energy. In the form of coal could be used in the production of ethanol, this. Might have an ER Oei of less than 1 but could still be desirable, due to the benefits, of liquid fuels assuming, the latter's are not used in the processes, of extraction. And transformation. Topic. Additionally. Our Oei, calculations. There, are three prominent expanded. ER Oei calculations. They a point of use extended. And societal. Point. Of view CRO AI expands. The calculation. To include the cost of refining and transporting. The fuel during the refining process. Since. This expands, the bounds of the calculation. To include more production, process, er OE I will decrease. Extended. Er OE I includes. Point of use expansions. As well as including, the cost of creating the infrastructure, needed for transportation. Of the energy, or fuel once refined. Societally. ROI is a sum of all the ER OE eyes of all the fuels used in a society or nation a. Societally. ROI has, never been calculated. And researchers, believe it may currently be impossible, to know all variables, necessary. To complete the calculation. But attempted, estimates, have been made for some nations. Calculations. Done by summing all of the ER o e is for domestically. Produced and. Imported, fuels and comparing, the result to the Human Development Index. HDI a. Tool often used to understand, well-being in a society. According. To this calculation the. Amount of energy a society, has available to them increases, the quality of life for the people living in that country and countries, with less energy available. Also have a harder time satisfying. Citizens, basic, needs, this. Is to say that societally. ROI and overall quality of life are very closely, linked. Topic. ESO. AI. ESO. AI or s wah is used when er OE is below 1s waar is the ratio of electrical. Energy stored. Over the lifetime of a storage device to the amount of embodied, electrical. Energy, required, to build the device. One, of the notable outcomes. Of the Stanford University.
Teams Assessment. On eso I was, that if pumped-storage was, not available, the combination, of wind energy and, the commonly suggested, pairing with battery technology. As it presently exists. Would not be sufficiently, worth the investment, suggesting. Instead curtailment. Topic. Er, Oei under, rapid, growth. A related. Recent, concern, is energy cannibalism. Where energy technologies. Can have a limited, growth rate if climate neutrality, is demanded. Many. Energy, technologies. Are capable of replacing, significant, volumes of fossil fuels and concomitant greenhouse. Gas emissions. Unfortunately. Neither, the enormous, scale of the current fossil, fuel energy system. Nor the necessary, growth rate of these technologies. Is well understood within the limits imposed by the net energy produced, for a growing industry, this. Technical, limitation. Is known as energy cannibalism. And refers to an effect where rapid growth of an entire energy producing, or energy efficiency industry. Creates, a need for energy that uses or cannibalizes, the, energy of existing, power plants or, production, plants, the solar breeder overcomes, some of these problems. A solar. Breeder is a photovoltaic, panel. Manufacturing. Plant which can be made energy independent. By using energy derived from its own roof using its own panels. Such. A plant, becomes, not only energy, self-sufficient. But a major supplier, of new energy, hence the name solar breeder. Research. On the concept, was conducted, by center for photovoltaic, engineering. University. Of New South Wales Australia. The. Reported, investigation. Establishes. Certain, mathematical, relationships. For the solar breeder which clearly indicate, that a vast amount of net energy is available from such a plant for the indefinite future, the. Solar module, processing, plant at frederick maryland was originally, planned as such a solar, breeder in. 2009. The Sahara solar breeder project, was proposed by the Science, Council of Japan as a cooperation. Between Japan and Algeria. With the highly ambitious goal of creating hundreds. Of GW, of capacity, within 30 years. Theoretically. Breeders, of any kind can be developed, in practice. Nuclear, breeder reactors, are the only large-scale. Breeders, that have been constructed, as of 2014, with, the 600. MW ebn. 600. And 800 MW, ebn. 800, reactor, the two largest, in operation. Topic. See, also. Embodied. Energy. Emerge-ii. Energy. Balance energy. Cannibalism. Exergy. Useful, energy. Jevons. Paradox, 1880s. Observation. Of the efficiency, effect multiplier. Kazoom. Brooks postulate, 1980s. Updating, of Jevons paradox. Cost. Of electricity, by, source levelized. Cost of energy. Social. Metabolism.
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