Energy Analysis developed alongside the expansion of Systems Ecology during the 1970s rather than following it as a separate stage. Many of the regional studies described in the preceding section required comparisons among very different kinds of energy. Sunlight, water, organic matter, fuels, electricity, and other energy sources could all be expressed in energy units, but equal quantities did not have equal abilities to perform work within a system. The problem was therefore not simply how much energy flowed through a system, but how energies of different kinds and quality could be compared.
The regional studies of South Florida undertaken during the early 1970s to evaluate the environmental consequences of development on the Everglades were one setting in which this problem became especially important. Natural ecosystems, agriculture, cities, and the regional economy were driven by energy sources of very different kinds. Fossil Fuel Work Equivalents provided an early means of expressing some of these energies on a comparable basis. At the same time, Odum was developing the more general idea that the transformations required to produce different forms of energy were related to differences in their quality and their roles within a system.
By the early 1970s, the problem of energy quality was already becoming explicit in Odum’s work, and by the middle of the decade Energy Analysis had become a major area of research. The energy crises of the decade focused national attention on energy supply, net energy yield, and alternatives to fossil fuels. In 1976 Odum published a remarkable series of papers dealing with net energy, alternative energy investments, energy quality, carrying capacity, environmental health, and alternative energy sources for the United States. That same year H.T. and Elisabeth Odum published Energy Basis for Man and Nature, bringing systems concepts and energy analysis together in an examination of the energetic basis of natural and human systems. The first edition did not yet develop hierarchy as an organizing principle; that became much more explicit in the second edition published in 1981.
A central issue in this work was energy quality. Conventional energy accounting could compare energy sources in calories or joules, but Odum argued that this ignored fundamental differences in their ability to perform work. In Energy Quality and Carrying Capacity of the Earth, published in 1976 from his address accepting the Prize of the Institute de la Vie, he described chains of energy transformations as forming a hierarchy of energy quality. Larger quantities of lower quality energy were transformed into smaller quantities of higher quality energy, and energy quality could therefore be related to the energy required in the transformations producing it.
These ideas placed Odum outside much of the developing mainstream of net energy analysis. At the NSF Workshop on Net Energy at Stanford in the mid 1970s, he argued that net energy calculations needed to recognize differences in energy quality. Simply comparing the quantities of energy used and produced could give misleading results if all forms of energy were treated as equivalent. The disagreement helped define a problem that occupied much of the work that followed: developing a quantitative procedure for comparing the many different energies supporting environmental and economic systems.
A major step came with the Department of Energy project that culminated in the 1979 report Energy Basis for the United States. The 444 page study was one of the principal settings in which Energy Analysis was developed into a comprehensive methodology. Systems diagrams, simulation models, net energy calculations, energy quality, and economic analysis were brought together at the scale of the national economy. Of particular importance was the recognition that the energy basis of the economy included not only fossil fuels and other purchased energies, but renewable environmental inputs and the energy embodied in goods and services. The project provided an extensive laboratory for developing and testing methods for evaluating these very different contributions. The report also included explicit analyses of embodied energy in goods and services, including solar inputs, and simulation of the coupled economy and environment.
An equally important methodological advance came through work for the Nuclear Regulatory Commission on the use of Energy Analysis in power plant siting. The project required environmental contributions to be quantified systematically rather than simply recognized conceptually. Procedures were developed for calculating the available energy of renewable sources such as sunlight, rain, wind, rivers, tides, and currents, together with nonrenewable resources and inputs from the economy. Before this work there had been no standardized set of procedures for quantifying all of these environmental energies within a common Energy Analysis. The resulting Manual for Using Energy Analysis for Power Plant Siting, completed in the early 1980s, provided a much more rigorous basis for environmental energy accounting.
This step was fundamental to what followed. Before energies of different quality could be compared, the available energy of each source first had to be determined consistently. Once those energies were quantified, energy transformation ratios could be calculated to relate higher quality energies to the lower quality energies required for their production. The power plant siting work therefore helped establish much of the quantitative machinery that would later make emergy accounting possible, even though the terminology of emergy and transformity had not yet been adopted.
During these same years, systems thinking was also becoming an educational objective. Elisabeth Odum was an environmental educator and an important influence in the effort to translate systems concepts into forms that could be taught. The objective was broader than teaching students about energy. Systems thinking offered a way of integrating subjects normally taught separately and of helping students understand the relationships among environment, society, resources, and their own place within the larger systems of which they were part. This work produced publications on environmental education in 1980 and teaching materials including Energy and Environment in Florida and Energy and Environment in New Zealand. The educational effort ultimately contributed to a broader program of teaching systems thinking and environmental relationships.
The effort to develop a more general systems science was also evident in a 1981 NSF workshop held in Gainesville. Researchers working in systems science, energy, ecology, environmental design, landscape architecture, and related fields were brought together to consider the research needed for a basic science of the coupled system of humanity and nature. The results were published as Research Needs for a Basic Science of the System of Humanity and Nature. The workshop reflected the increasing scope of Systems Ecology: the objective was no longer simply to understand ecosystems or energy flows, but to develop principles and methods applicable to systems in which humanity and nature were inseparably connected.
By the early 1980s, hierarchy was becoming much more explicit in Odum’s systems thinking. Although the concept of an energy quality hierarchy had appeared in his 1976 Institute de la Vie paper, hierarchy was not developed in the first edition of Energy Basis for Man and Nature. It appeared in the revised 1981 edition and became increasingly important thereafter. In 1982, Pulsing, Power, and Hierarchy connected hierarchical organization with another developing idea: systems often operate through cycles of gradual accumulation followed by pulses of rapid consumption and reorganization. The pulsing paradigm challenged the assumption that sustained steady state operation was necessarily the characteristic form of a sustainable system.
These developments were brought together in Systems Ecology: An Introduction, published in 1983. Hierarchy was now an important part of the systems framework, while the quantitative treatment of energy quality continued to evolve. Energy transformation ratios related higher quality energies to the lower quality energies required for their production, and several common bases were being explored, including coal equivalents and global solar energy equivalents. The terminology was still evolving, but the underlying methodology was becoming increasingly clear: trace the energy transformations supporting a product or process and express energies of different kinds in terms of a common energy basis.
Another major development occurred in 1983 when H.T. and Elisabeth Odum worked at the International Institute for Applied Systems Analysis in Austria. There they developed formal procedures for applying Energy Analysis to national economies and international trade. Energy Analysis Overview of Nations applied the methods initially to a group of countries and established a systematic framework for national accounting. The resulting IIASA working paper was 469 pages and established the framework from which the later National Environmental Accounting Database developed.
By the early 1980s, Energy Analysis had developed from the comparison of individual energy sources into a systematic framework for evaluating the environmental and economic inputs supporting ecosystems, regions, and nations. Methods for quantifying renewable and nonrenewable energies had become increasingly standardized, while energy quality, transformation ratios, hierarchy, and a common solar energy basis provided ways of comparing energies of different kinds. The quantitative framework was largely in place; what remained was to refine its common basis and develop a terminology that clearly distinguished it from conventional energy accounting.
Milestones and Key References
1973–1976 — Energy quality and net energy
Odum increasingly distinguished energy quantity from energy quality and argued that net energy evaluations had to recognize differences among energy forms. Work during this period culminated in the 1976 Energy Quality and Carrying Capacity of the Earth, where transformation chains were explicitly described as a hierarchy of energy quality
Energy Quality and Carrying Capacity of the Earth — H.T. Odum (1976)
Energy Analysis and Net Energy – H.T. Odum (1976)
1976 — Energy Basis for Man and Nature
H.T. and Elisabeth Odum brought energy analysis and systems concepts together for a broad audience, examining the energy basis of environmental and human systems. The substantially revised 1981 second edition incorporated hierarchy much more explicitly.
Odum, H.T. and E.C. Odum. 1976. Energy Basis for Man and Nature. McGraw-Hill, NY. 297 pp.
1979 — Energy Basis for the United States
The 444-page Department of Energy study brought renewable environmental inputs, fuels, embodied energy in goods and services, economic activity, systems diagrams, simulation, energy quality, and net energy together in a comprehensive national analysis. In my view this should be one of the visually prominent milestones on the page because of its methodological importance.
Odum, H.T., J.F. Alexander, F. Wang, M. Brown et al. 1979. Energy Basis for the United States. Report to Dept. of Energy, Washington, DC. Contract EY-76-S-05-4398. 444 pp.
1981–1983 — Standardizing environmental Energy Analysis
The Nuclear Regulatory Commission power-plant-siting work established systematic procedures for quantifying renewable and nonrenewable environmental energies and relating them to economic inputs. It provided much of the quantitative foundation upon which later emergy accounting was built. The report itself documents free environmental energies as explicit inputs to the accounting.
A Manual for Using Energy Analysis for Plant Siting — H.T. Odum et al. (1981).
1982–1983 — Hierarchy, pulsing, and Systems Ecology
Pulsing, Power, and Hierarchy connected energy hierarchy with pulsing behavior, followed in 1983 by Systems Ecology: An Introduction, which synthesized energy flow, hierarchy, feedback, modeling, and energy quality within a general systems framework. The archive identifies the original 1982 paper and the 1983 book in contemporary bibliographies.
Pulsing, Power, and Hierarchy – H.T. Odum (1982)
1983 — National Energy Analysis
At IIASA, H.T. and Elisabeth Odum and collaborators developed systematic procedures for evaluating nations and international trade. Energy Analysis Overview of Nations applied the approach across countries and established the framework from which later national environmental accounting developed.
Energy Analysis Overview of Nations – Odum, H.T. and E.C. Odum, eds. (1983).