"Most people in the industrial world today seem to have lost the ability to imagine a future that doesn’t have electricity coming out of a socket in every wall, without going to the other extreme and leaning on Hollywood clichés of universal destruction. The idea that some of the most familiar technologies of today may simply become too expensive and inefficient to maintain tomorrow is alien to ways of thought dominated by the logic of abundance.
That blindness, however, comes with a huge price tag. As the age of abundance made possible by fossil fuels comes to its inevitable end, a great many things could be done to cushion the impact. Quite a few of these things could be done by individuals, families, and local communities...Despite this, very few people are doing them, and most of the attention and effort that goes into responses to a future of energy constraints focuses on finding new ways to pump electricity into a hugely inefficient electrical grid, without ever asking whether this will be a viable response to an age when the extravagance of the present day is no longer an option.
This is why attention to the economics of energy in the wake of peak oil is so crucial. Could an electrical grid of the sort we have today, with its centralized power plants and its vast network of wires bringing power to sockets on every wall, remain a feature of life throughout the industrial world in an energy-constrained future? ...The question that has to be asked instead is whether a power grid of the sort we take for granted will be economically viable in such a future – that is, whether such a grid is as necessary as it seems to us today; whether the benefits of having it will cover the costs of maintaining and operating it; and whether the scarce resources it uses could produce a better return if put to work in some other way."
- John Michael Greer, The Logic of Abundance
The necessary life support that nature offers for free begins to diminish when an area becomes about 50 percent developed by humans. At that point, further economic growth of the area may result in an actual net loss because of higher energy drains. For example, an area that naturally accepted and reprocessed waste waters gets paved over, and then requires the construction of an expensive and energy hungry waste treatment plant. What was formerly done for free by nature is gone and we now have to pay for the service.
As urban areas grow, we tend to put a lot of energy into the development of technologies to protect the environment from our wastes. However, most wastes are actually rich energy resources, and ecological resources are capable of reprocessing these wastes into useful energy. If growth is so dense that complex technology is required to deal with its wastes, then it is too dense to be economically vital for the combined system of man and nature. Man as a partner of nature must use nature well, not crowding it out, paving it over, or developing industries that compete with nature for the waters and wastes that would be a contributor to the survival of both.
Advocates of major energies available from the sun don’t understand that the energy from the sun, while very large in volume, is very dilute in quality. Therefore, a large amount of subsidized energy (usually from fossil fuels) is required to concentrate the sun’s energy to upgrade it to electricity.
Plants are actually the most efficient processors of solar energy using photosynthesis. They build tiny microscopic semiconductor photon receptors that are the same in principle as solar cells made by humans. The difference is that the plants are able to build these processors out of the energy budget that the sun allows. The reason major solar technology has not and will not be a major contributor of substitute for fossil fuels is that it will not compete without energy subsidy from the fossil fuel economy. Some energy savings are possible in house heating on a minor scale.
[The above is a controversial point, but there are many who agree with Odum’s position here, such as David Holmgren and John Michael Greer. Rich Dryer, an energy industry engineer, put it well: “Those studies which purport to show positive net energy have simply excluded large chunks from the necessary life-cycle analysis. Just enumerate the energy cost of the factory to make the truck to mine the silicon ore, the energy to make the truck to transport that ore to another factory and its construction and operating energy cost, the energy to design, fabricate, transport, construct, operate, maintain, repair and recycle the cells. All of that is currently powered by hydrocarbon. Now plug that entire supply chain back into its own energy output and try and maintain “business as usual” in a world that until now didn’t have to do *any* of that and is struggling with hydrocarbon depletion.”
However, I found a good piece from 2006 (Energy Payback of Roof Mounted Photovoltaic Cells) that helped me get clear on my own position that Odum, Holmgren, and Greer are wrong in saying solar pv will never yield net energy. Colin Bankier and Steve Gale analyzed numerous other studies, fond what they think is the best one, and further refined its findings. When they included Odum's methodologies, they found that the average rooftop system will tend to have a positive energy payback in about 4 years.
Odum had done a study in 1996 of a centralized solar power plant that showed solar pv used twice as much energy as it provided in its lifetime. So centralized solar power plants may be a bad idea; however decentralized, distributed solar pv installed on rooftops of already existing buildings is net yielding.]
Odum is here telling us that not all energy is equal. We can’t just measure quantity, we also have to consider quality. Energy can be upgraded to a higher quality (available to do more work), but there is always a net loss of total energy in the upgrading process – this is the basic law of entropy in physics.
From his book, “Energy Basis for Man and Nature,” Odum writes: “Some forms of energy, like sunlight, are very dilute; others, like gasoline, dynamite, and high-voltage electricity, are very concentrated. A Calorie of dilute energy cannot be used in the same way as a Calorie of concentrated energy. Furthermore, it takes energy to concentrate energy. We must degrade some energy in order to concentrate what is left…Four Calories of coal are required to make 1 calorie of electricity; 1,000 Calories of sunlight may be required to make one Calorie of wood.”
Odum ends point number 14 above with saying computer and human information processing represents a very high energy quality. How so? Again, from “Energy Basis for Man and Nature”: “People sometimes make mistakes in deciding what activities ultimately cost or do not cost much energy…We are so used to thinking of energy as physical processes that we do not realize that thinking uses energy too. The energy is in all the work that goes into educating the mind and maintaining the body to support the mind…Because much energy is used in developing one’s abilities, intellectual activity is a very high-quality use of energy; intelligence and learning are concentrated potential energy.”