By Mary Logan
This is part two of a three-part series revisiting HT Odum’s classic Ambio paper on the 3Es, which was written 40 years ago for a special issue of the Royal Swedish Academy of Science’s Energy in Society issue (Ambio, 1973). The article was republished in Mother Earth News, and the reprint is still available online through Minnesotans for Sustainability. The first 10 points are covered in part one of the post series. Points 11-15 of the Ambio paper are extracted and quoted below; in this section of the paper Odum described the not-yet named field of ecological engineering, as well as energy quality (transformity), and the net energy of solar and nuclear energy.
11. “Even in urban areas more than half of the useful work on which our society is based comes from the natural flows of sun, wind, waters, waves, etc., that act through the broad areas of seas and landscapes without money payment. An economy, to compete and survive, must maximize its use of these energies, not destroying their enormous free subsidies. The necessity of environmental inputs is often not realized until they are displaced” (Odum, 1973).
Our biosphere serves many supportive purposes such as provision of stabilizing diversity, waste removal, recycling, the food chain, buffer temperature, climate control, and other cultural services. The more we expand our populations and built space over the landscape, the less the biosphere can offer its free services to the human economy. For example, fresh water in rain, snow, river energy, and fresh water do work and carry chemical potential energy. The water cycle organizes the landscape and human commerce. Products of mines, agriculture, forests, fisheries and lands give between several orders of magnitude more to the economy than their market values. The list of support services is another post in and of itself; reading a good ecology textbook is recommended in order to understand the full import of our dependence on our environment.
When we pave over too many of these supporting ecosystems, or assign “ecosystem services” to too many competing tasks, we use circular reasoning and third order consequences to assign too many roles to failing biota. If we need to keep up the biota for support of the whole system, then natural resources cannot be used or expanded for non-fossil fuel-based agriculture, biofuel production, population expansion, dispersal, or migration, mining, and other uses. A newly developed energy source may be one already contributing to the economy through solar, wind, waves, tides, or as biomass. Industrial scale development of many renewables is not sustainable for this reason. And pollution in the air, water, or land diminishes economic wealth as we must use resources to deal with the effects.
12. “Environmental technology which duplicates the work available from the ecological sector is an economic handicap” (Odum, 1973).
If we attempt to use high-tech solutions to replace natural subsidized work of the environment, we create more energy demands on the system that we cannot afford, in addition to creating added pollution loads on the environment. In complex economies buoyed by fossil fuels, crowded urban settings require increased use of pesticides, high-tech processing of human sewage, climate control, flood control, and many other substitutions for nature’s work. Ecological engineering is the idea that we need to work with nature and not against her in our quest for sustainability.
Odum first described ecological engineering in 1962 as “those cases where the energy supplied by man is small relative to the natural sources but sufficient to produce large effects in the resulting patterns and processes” (H.T. Odum, 1962). The goals of ecological engineering are restoration of disturbed ecosystems and development of new sustainable ecosystems that integrate human society with its natural environment, for the benefit of both (Mitsch, 2012). These goals can include solving a pollution problem, reducing a resource problem, recovering or modifying ecosystems in an ecologically sound way, and using ecosystems for benefit without destroying the ecological balance (Mitsch & Jorgensen, 2004). For example, waste waters can be recycled on agriculture or in wetlands, as wetlands are nature’s kidneys. In the future, economies with wastes will not compete.
13. “Solar energy is very dilute and the inherent energy cost of concentrating solar energy into form for human use has already been maximized by forests and food-producing plants. Without energy subsidy there is no yield from the sun possible beyond the familiar yields from forestry and agriculture” (Odum, 1973).
Chloroplasts in plants are solar voltaic cells that generate electricity in biochemical systems of the plant cells. These plants are critical to the ecosystem support of an overburdened planet. If we replace nature’s green solar voltaic cells by manmade solar photovoltaic (PV) cells of silicon, we are adding many layers of added energy, matter, and information, at great cost to society, in order to get efficiencies and power output that is arguably not better than that of a plant, which additionally provides natural services to the biosphere. Since economic valuations fail to consider the very large emergetic costs of solar PV, grossly optimistic valuations for renewable energy result. Green plants are the best solar voltaic cells known, and solar PV can’t replace green plants as the main source for a lower energy world.
The rather dated net emergy evaluations above illustrate the relative emergy yield of electricity derived from various electric power sources. From Odum’s perspective, solar PV is not and has never been net yielding. This view has been borne out by the repeated general failure of the solar PV industry over time. Those who view solar PV as net energy-yielding fail to see the transformity of the many steps needed to create high-tech simulacrums of one of nature’s biggest gifts. Odum’s diagrams below compare electric generation from a modern-day solar PV plant in Austin Texas with a wood power plant operated from old-growth logs in the Amazon, illustrating how time is necessary to concentrate dilute energies for a net yield. The wood-fired power plant is very simple, benefitting from the stored emergy basis of rainforest trees that have concentrated sunlight over many years. The solar PV plant muscles highly transformed goods and services from high-tech industries to try to replicate a chloroplast. As Odum (2007) states, “Evaluations that claim net yield from solar cells leave out the huge empower required in the human services for manufacture, distribution, support connections, operation, management, and maintenance” (p. 209).
14. “Energy is measured by calories, Btu’s, kilowatt hours, and other intraconvertible units, but energy has a scale of quality which is not indicated by these measures. The ability to do work for man depends on the energy quality and quantity, and this is measurable by the amount of energy of a lower-quality grade required to develop the higher grade. The scale of energy goes from dilute sunlight up to plant matter to coal, from coal to oil to electricity and up to the high-quality efforts of computer and human information processing” (Odum, 1973).
Odum’s description here of energy quality was later developed quantitatively into the principle of emergy transformity; energy memory accumulates into more concentrated forms in a hierarchy of energy. At each step in the food chain, most energy is degraded as heat and a small part is passed upwards to the next step in the food chain. So in the example at right, while the actual physical energy embodied in a hawk is small, the accumulated emergy basis from lower contributions in the food chain remains, as the energy memory of all the energy that went into the making of that hawk. The diagram below illustrates the means of calculating an emergy basis, based on the pictorial representation above.
While this idea of an energetic food chain within the animal kingdom is a basic ecological principle, what most people do not understand is that the transformations continue up into human economy, courtesy of the addition of high-quality, non-renewable fossil fuels that allow the pyramid of complexity to become much higher. The diagram below shows the expansion of nature’s food chain into modern society through the addition of fossil fuels, illustrating the real embodied costs of human labor. We mentally separate the human economy from the natural one, which provides an illusionary immunity from the thermodynamic laws. But there is no separation, and our human economy is subject to the laws of nature. The human economy exists within the environment, and it is only the fossil fuel-based support that allows us to believe differently.
Just how much of our complex post-industrial society is sustainable without surplus fossil fuels when using this logic and algebra, especially when we consider the size of our global population and the amount of resources that actually contribute to our advanced economy? When we view Tom Abel’s pictorial representation of a fossil-fuel-boosted human economic food chain below, one can see that the upper tiers of the system are probably not supportable once the high quality non-renewable energies are reduced, if we adhere to the second law of thermodynamics. How much energy is embodied in our legal codes in a complex society, for example? What are the costs of changing that code as society descends, and how much complexity can be supported? How much of first-world economies in general are supportable given the limited environmental support to draw from as fossil fuel inputs wane? When we understand just how much energy memory is represented in modern society, we begin to fathom the adaptations that will be necessary in descent.
15. “Nuclear energy is now mainly subsidized with fossil fuels and barely yields net energy” (Odum, 1973).
On the topic of nuclear net energy, Japan’s Fukushima nuclear accident illustrates the eventual outcomes of a high-risk, marginal net energy pursuit. Those energy sources with marginal net yields are more expensive economically, and they are also more damaging to the environment.
“No one really knows the net yield of nuclear power because at present its use is subsidized by fossil fuels in a thousand ways that cannot be estimated until we try to run a nuclear system without them. Will nuclear power have a more concentrated value than the wood output of the solar system, or of coal, or of cheap oil from rich deposits? The new power plant seems to be more economical than the competing fossil plants as long as it is running on the accumulated storages of nuclear fuel and fuel prospecting done on fossil-fuel subsidy. Is nuclear power at this level of net power delivery possible in a culture that does not have the accompanying fossil fuels?” (Odum, 1971, p. 135). ” Nuclear energy does not yet yield net energy. Even if the present plants last as long as they are supposed to, without major accidents or deterioration, they will yield less energy per unit of energy invested than other sources. Another principle of energy applies here: it is impossible to build new structures when there has been no recent growth to generate the necessary capital.(p. 9) Some net energy will eventually result, but the energy cost of getting nuclear energy into usable form is very high. How high is not yet clear” (Odum & Odum, 1976, p. 180).
Odum calculated net emergy ratios of nuclear of 2.7 to 4.6, historically. But these valuations did not count the long-range costs of waste storage, decommissioning, and accidents. Is nuclear still net energy, in a world with declining non-renewable energy flows? Japan’s quandary suggests that nuclear power is not net yielding. What is in store for the rest of the nuclear power plants globally, given Japan’s failed nuclear experiment and its impact on the biosphere? Other posts on the subject are available here.