Renewable Power Rhythm


by David Tilley, University of Maryland


Hunger Games Capitol City (Collins, Ross, Lionsgate)


US Emergy Consumption 1790-2000 (Tilley, 2006) (link at end of article)

The flow-limited energies that will be available will come mainly from wind, rivers, biomass and a little from solar voltaic. Life during the storage-driven era of fossil-fuels lead society to be able to control the availability of energy. People could consume energy by flipping switches and turning ignition keys. Energy was available when people wanted it. This convenience lead society away from the temporal constraints that were present before the industrial, fossil-fueled age. In the pre-industrial period, most work would need to be accomplished during daylight because that was when light was

US Emergy Consumption 1790-2000 Renewable Fraction (Tilley, 2006)

available to see. A farmer’s life was tied intimately to the rhythms of the day and seasons. The industrial period’s electric lights allowed factories to operate at night and cars to be driven in the dark. Today, homes equipped with electricity in the developed world rarely experience the inconvenience of no electric power, except during the occasional storm. There was little rhythm to the use of energy in the industrial age that was driven by the availability of energy. Certainly there were cycles to the consumption of power that were tied to large scale phenomena like world wars and global depressions. Also, there were global politics that affected the short term (i.e., a few years) availability of oil, but never were natural forces at work to drive the rhythm of the consumption of energy.

In the post-PWD, when energy is derived almost exclusively from wind, rivers, and biomass, humanity’s consumption of energy will be tied to the natural, global cycles of the Earth’s planetary, energy-transforming systems. The availability of wind is intermittent with periods of high, medium and low intensity. Rain and snowfall that feeds rivers and reservoirs, and drives the productivity of crops is cyclical. El Nino/La Nina is one of the better-known global cycles whereby Pacific Ocean sea surface temperatures drive rainfall and temperatures across continents. How will the rhythms of major flow-limited energy sources work together to determine how society organizes its major functions like food production, building construction, information processing, socializing, and travelling?

North Carolina Hydro-Electricity and Rainfall (Tilley, 2006)

The record of electricity production from hydro-dams in the North Carolina during the end of the 20th Century shows that power availability was directly tied to the amount of rainfall, which varied slightly (at right). During dry years, the amount of electricity available was lower than wet years. Monthly variability was likely present too, but suppressed by the large storage of the reservoirs. Thus the scale of the cycle was annual. Geographical locations appropriate for generating electricity from wind often experience seasonality in wind speeds, which directly affects electricity production. In North America wind speeds tend to be greater during the Winter than during the Summer. Also there are often periods of strong winds followed by periods of weak winds. The rhythm of wind has intra-annual, weekly and daily cycles. Power from biomass will be tied to rainfall patterns.

Electricity will remain to be available in the post-PWD, but its availability will have decadal, annual, monthly, weekly, daily and hourly rhythms. Large scale storage of electricity is difficult today and will likely be difficult in the post-PWD. The portion of society that continues to use electricity will need to adapt to these rhythms. When power is highly available, economic and social activities that rely upon electricity will ramp up quickly to dissipate the generosity of the planet and make needed goods and services. Conversely, when power is scarce, those same activities will be suppressed or shut-down.

I can imagine computing-based industries like banking, data-processing, and software programming, will need to arrange work schedules to coincide with the availability of power. Work will be fierce during excess power, but maybe non-existent when it is scant. Socializing that is computer based can also occur when extra power is temporarily available.  Long-distance travel will be tied to those periods when extra biomass is produced to make liquid fuels.

Scuddy weather? “Windmill Near Zaandam” 1871 Claude Monet

Maybe the rhythm of the various energy sources will be asynchronous so that when wind-powered electricity is low, hydropower is plentiful. However, its more likely they may be synchronous, which means that peoples’ down time will need to be fulfilled with non-electric activities like listening to acoustic music or playing games and sports. If winds are highest during the winter, then biomass production and wind-power will be asynchronous, which would allow people to work in agriculture during the summer, but work in information-processing during the winter. The extra heat generated by the electrical devices would come in handy to keep indoor temperatures comfortable.

Solar photovoltaic technology will likely not play a large role in energy availability in the post-PWD due to its low energy return on energy invested. However, it will find highly specialized uses in space satellites and military actions.

Will major religions be able to adapt their teachings to reflect the need for society to adapt to the rhythms of flow-limited energies? Capitalist-Democracy has proven some ability to self-organize to adapt to energy availability during the last few centuries. Will they continue to adapt? How will government adapt to flow-limited, intermittent energies?

This post is only the beginning of a conversation on the adaptability of humanity to the rhythms of flow-limited, intermittent energies in the post-PWD world. I hope to see others respond to the idea. It is virgin intellectual territory. The future will not be like the past because we will have electricity. How will electricity be connected to human activities in the future, when it is rare and highly prized?

Tilley, D.R. (2006). National metabolism and communications technology development in the United States, 1790-2000. Environment and History, 12(2), 165-190.

18 thoughts on “Renewable Power Rhythm”

  1. Dr. Tilley, thank you for this post. You ask a question at the end of the article, “The future will not be like the past because we will have electricity. How will electricity be connected to human activities in the future, when it is rare and highly prized?”

    I am reminded of what John Michael Greer wrote in a post called “The World After Abundance”:





    On another point, I wonder if there has been a recent emergy analysis of solar pv. You write: “Solar photovoltaic technology will likely not play a large role in energy availability in the post-PWD due to its low energy return on energy invested.”

    I know Odum did an analysis that he wrote about in 1996 (Energy Accounting). But it was pointed out by Bankier and Gale that what Odum evaluated was “a utility scale solar voltaic power installation.” If you look instead at a distributed network of roof-mounted solar pv, and then also take into account recent efficiency improvements, the energy return on energy invested appears to look much, much better.

    [Ed note: URLs removed for suspected malware 5/1/16]

    Now, I don’t want to give the wrong impression. Although I have come to believe solar pv can yield net energy, it is still clear to me that “Renewable Energy Cannot Sustain Consumer Society,” as Ted Trainer has put it. I fully support the need to find a Prosperous Way Down, and that ” the extravagant habits of the recent past and the present will no longer be an option” in the post carbon world.

    1. In response to David MacLeod’s question about recent emergy analyses of solar PV…
      C. Paoli, P. Vassallo, M. Fabiano, 2008. Solar power: An approach to transformity evaluation. Ecological Engineering vol. 34 pp. 191–206

      Kindberg, A. (2007). Emergy evaluation of a Swedish nuclear power plant. Uppsala University Neutron Physics Report (ISSN 1401-6269)

      Paoli et al (2008) evaluated a small solar plant in Italy that used monocrystalline silicon (BP Solar BP585F) PV panels that covered 136 m2 (~1500 ft2), faced south at 30 degree inclination, and had max power output of 18,300 watts at 8% efficiency. This would be equivalent to a few home roof tops. The energy return on energy invested (i.e. Emergy Yield Ratio) was 1.03, meaning that 3% more energy was yielded than diverted from the economy for investment. Thus, zero return is surely within the margin of error and shows that PV is not a primary source of energy. In addition, they estimated that 28% of the total energy required to produce electricity with PV came from electricity! Another 23% was need to make the inverters and another 20% for maintenance costs.
      HT Odum argued from a emergy-based viewpoint that making the leap from visible radiation of solar power with its solar transformity of one sej/J to electricity with a mean solar transformity of 250,000 sej/J, meant that PV was making too giant of a leap across the energy hierarchy. From a practical perspective that leap means that PV has to be a very inefficient means of making electricity. On a side note I once estimated that the weather system used about 1,000,000 solar joules to make 1 joule of lightening. Nature is typically not efficient. The planet’s weather system works on about a 9% efficiency at transferring solar power into weather (winds, sea currents, etc). Photosynthesis is less than 1% efficient. However, nature is great at doing a lot things at one time (ie. biodiversity is huge even though its powered by 1% efficient machinery). That is another thing that the industrial/fossil age has biased us about. High Efficiency is an aberration.

      If I take Paoli et al. (2008) analysis and assume that the system is connected to the grid (maybe there’s was), then I can argue that the energy return for substituting PV electricity for fossil fuel electricity is 1.96:1. That’s better than 1.03, but it requires that I be connected to one of those huge grids that you mentioned Greer railing against. If PV is to play a significant role in the post-carbon world, its non-grid return on energy needs to be at least 2:1, which is a bare minimum and nowhere near what we currently get from fossil fuels and uranium. A recent Swedish emergy analysis (Kindberg 2007) estimated that their country’s nuclear plants have a mean 12:1 return on energy.
      Thus, PV’s 1.03 return says that it will most likely never be a primary source of energy. Biomass, wind and hydroelectricity have better energy returns, so I think they are what will power us in the future.

      Thanks for the comment. I will go read Greer’s post now.

      1. Thank you for the reply, and the reference to Paoli, et al. I did a search and was only able (for free) to access the abstract…which confused me, because the tone seems to be somewhat at odds with your statement, so I hope you can explain. In fact, it would be great if there were a full fledged post here, summarizing in layman’s language the results of that study (I wasn’t a science major, and sometimes struggle in my understanding), and perhaps responding also to the article Energy Payback of Roof Mounted Photovoltaic Cells by Colin Bankier and Steve Gale (

        From the abstract of the Paoli, et. al paper you referenced: “solar technologies imply a remarkable emergy saving (5.72E+15sej/year for thermal and 4.77E+15sej/year for photovoltaic). These evaluations make solar power technologies advisable in order to save non-renewable resources. Moreover, the analysis demonstrated recent and remarkable improvements in photovoltaic electricity production efficiency. This condition sets a positive scenario considering the expected and outstanding further improvements in solar technologies.”

        Oh, I just re-found an article by Ugo Bardi that references the work of Raugei, Ugliati, et al. Bardi writes: “I discussed the results with one of the authors, Marco Raugei (incidentally, a former student of mine), and we arrived to the conclusion that, in favorable conditions of illumination (1700 kWh/(m2*year) and assuming a lifetime of 30 years, polycrystalline silicon has an EROEI of 15, while CdTe thin film cells have an EROEI of 40.”

        The paper referenced just talks about EPBT (energy payback time): “During the last 4-5 years, the progress in the major commercial technologies has been quite remarkable. The EPBT of thin film CdTe dropped 15-35% and that of Si technologies dropped 25-40% for specific companies.”

        1. I don’t know why the abstract of Paoli 2008 was so optimistic. It is clear from their calculations and analysis that solar PV had an Emergy Yield Ratio (EYR) of 1.03, which is basically zero. I think authors sometimes want to soften the blow of their results…but that is only one speculative thought. I know Ulgiati and Raugei well from our emergy meetings.

          As Ugo Bardi pointed out in the above post, the EROI is completely dependent on how to define the “what is required” to make the energy. Emergy analyses, when conducted in the style of Prof. Odum, draw the largest boundary so everything is included: fossil fuels, minerals, metals, acids, sophisticated chemicals, and most importantly human services. Thus, EYR will always be less than EROI for the same technology because the boundary is larger. Recall that both are trying to get at what society is “investing” or more precisely “dissipating” to make another type of energy. EROI never includes human service and typically ignores environmental inputs like soil for biofuel crop production. When human service is a large portion of the total “investment” then that is telling us that there is a huge “hidden” indirect energy cost. I addressed this in a paper in Energy (Felix and Tilley 2009). When an EROI calculation ignores this “hidden, indirect” dissipation, it misses a vast majority (sometimes more than 50%) of the energy required and can have a positive EROI when EYR is basically zero. Richard Heinburg has a table in The Party’s Over where he compares EROI and EYR. If you take a look at it, you will note that EROI is always higher. The difference is due to EROI’s exclusion of human and environmental energies.

          LCA are typically even more egregious in their definition of analytical boundaries. Many analyses of PV will quote the energy payback, but only compare the electricity produced to the direct electricity consumed. If you do that with Paoli’s (2008) study you would get a payback of 3 or 4 months. But this completely ignores all the other fossil fuels.

          We live in a society that gets 90% of its energy from fossil fuels and uranium. Anything we do or make has a 99% chance of having fossil fuels embodied in it. PV is no exception. They cannot make themselves!

  2. Mr. MacLeod, Greer’s comments regarding the number of transformations required for the energy basis for electricity (and thus also the very large entropic losses) can be quantified–electricity has about four times the energy basis of fossil fuels (table at the link). That’s one reason why electric cars, for example, are so inefficient. I’ll let Dr. Tilley respond to your comments about solar PV.

    Dr. Tilley, it would be fun to compile all of the ways that fossil fuel-based society has nullified our need to pulse? Malls are 7 days a week and internet shopping is global and 24/7, allowing consumption within our spinning flywheel economies to occur as fast as possible. Academia is shifting to year-round semester systems. Production and services have extended to an around the clock basis. Our sports’ seasons are extended by media promotion, indoor arenas, and global travel enabling us to take advantage of seasons in both hemispheres. Fishing boats are very large, with huge ranges, and year-round capabilities, even in the Gulf of Alaska. Faster and faster we go. I’m sure others can think of more examples?

    In my business, hospital-based healthcare is an example of people trying to adapt to a non-pulsing system. Healthcare delivery is 24/7. Hospitals have become 24/7 healthcare factories. We forget about the diurnal rhythms of patients, to the extent that patients become confused from sleep loss and stress. Humans are adapted for pulsing, and the lack of downtime in our society is maladaptive, as you point out. Perhaps some stress-related illnesses will improve in descent from regaining pulsing behaviors such as enough sleep, and weekends and evenings spent with families in real communication.

    Pulsing allows for reordering of the system (Odum, Odum, and Odum, 1995, linked below). Too big of a pulse in entrained energy, especially in systems with deficient storages causes chaos. Yet too small of a pulsing pattern in the system limits maximum power and limits evolution and adaptation. A true steady state in a system is a bad sign—I’m a cardiac nurse, and I know that variability is lost as we age and that steady-state cardiac rhythms are generally a bad sign. Yet we are now in a situation where we pulse less and less, yet are poised at the edge of chaos with copious amounts of surplus energy entrained into the system. Instead of yielding the system like a beach dune to the oncoming hurricane, we react by building more seawalls and dikes to hold things as they are.

    Alaska still has some big, natural pulsing patterns that defy industrial society. Our diurnal and seasonal patterns are epic, with long summer days of 18+hours and winter days of 5+hours of weak sunlight. Our economic base of resource extraction has big boom and bust cycles (fur, whales, gold, and oil). I like the pulses—we are forced up here to yield to Nature somewhat. Winters are downtime for introspection, rest, writing, crafts, storytelling, or sulking, depending on your inclination. Riding the larger pulses of resource booms draws a lot of resource extraction experts to Alaska. Yet the oil in the pipeline is waning, and the crude is becoming sour. There are proposals up here to put in a Susitna dam, which would supply our railbelt with consistent electric power for the future. Yet there is pushback from the environmentalists. HT suggested that hydropower might be crucial to the maintenance of centers of information in descent:

    “But electric power, with its transformity about 4 times that of fossil fuels, requires huge fuel flows and diversion of much of the energy of the mountain rivers that used to support other productivity. With less fuels available in the future, availability of electric power may control where the centers of information will continue. In fuel scarcer times ahead, there may be advantages in locating information centers near hydroelectric power. There may be advantages to those with proximity to mountains with high rain and snowfall” (Odum, 1995, p. 26).

    1. Thank you for pointing me to the Pulsing Paradigm article. I was just recently re-reading Holmgren’s chapter on “Creatively Use and Respond to Change” where he discusses the pulsing model, and from there I also re-looked at Odum’s PWD. Tilley’s post here, and the one you just referenced are excellent follow-ups!

      Did HT pioneer this concept within the field of ecology, or were other ecologists already promoting the idea of pulsing ecosystems? Holmgren references Odum, but also writes “Before ecologists had begun to question the classic climax models of succession and stability, in another field of natural science, geomorphology, this pulsing model was already widely accepted.”

      1. That’s a good question, David MacLeod, and one I tried to address at the link below–see if that answers some of your questions. If not, Goldsmith has some good critiques, linked in the post below. Ecology became more reductionist over time, focusing on a population ecology/evolutionary approach. Other sciences promote pulsing, but the idea that our society would ever either reach a climax or go anywhere but up was not a part of the modern ecological world view.

        Dave Tilley, you missed an opportunity in naming this post–you could have called it “Going With the Flow!”

  3. I realise this article was written to generate comment and opinion but: “long distance travel would only be possible when there was sufficient biomass to produce liquid fuels”, is to invite hilarious derision. Biofuel production EROEI is little better than 1:1!
    I also hope Mr Tilley or anyone he holds near and dear isn’t in intensive care during a low point of one of those “electricity flow rhythms”, or he will have to watch the medical staff playing cards, sports or listening to acoustic music.
    And no mention of our foodchain. All this ‘intermittent use’ nonsense when our entire food supply (and civilization itself) is geared to the flow system of supermarkets. Mr Tilley, 99% of the people in the developed west do not know where food comes from. It just appears on shelves through industrial farming and it is a far more important source of energy than flicking light switches. It is our consistent food supply that has allowed the human population to exceed the global carrying capacity, and that food supply is a product of hydrocarbon energy input. There is no other magical ingredient and the wishful imperative that we will all have to work the land in summer adds another note of black comedy here. No doubt the land can be worked by hand labour, but you ignore the fact that pre-industrial agriculture delivered a very low food surplus, (that’s why a lot of people died off) and just where is this land supposed to come from? Are the inhabitants of cities meant to trudge miles out into the countryside each morning to till the soil? And one can only shudder at the thought of the inhabitants of the next town conflicting over whose patch of ground it is. Our complex cities exist because every kind of energy can be fed in as needed; if we have to fetch it, the city dies.
    It would be as well to throw away rose tinted spectacles, our post industrial future is not going to be one where we sit around a village green in a state of bucolic bliss after a worthwhile day of toil.

    1. Hi, Medieval. Odum suggested that eventually our civilization would be reduced to 30% of the emergy that it enjoyed at its peak. That’s quite a descent. Tilley leaves a lot unsaid here about transition, which will probably be ugly if we do not plan for it proactively, you’re correct there. One point of this website is to jolt people out of their gasoline-induced stupor into proactive relocalization. What’s your plan?

      On the emergy basis of healthcare, I’ve worked in intensive care units during hurricanes where the only plugs that worked were the red ones, and those worked only through the temporary grace of Mr. Diesel. Electricity is the dividing line between what we’ve got now and something much simpler. The nature of on-and-off or patchy electricity distribution during transition is something worth talking about?

      Mary Logan

  4. My co-author and I have been struggling with this subject for 3 years, when we started, it seemed easy, over time we’ve diverted our efforts to warning anyone who will listen that there is no ‘plan’.
    We have 3 problems: Energy depletion, Overpopulation and food shortage. Lots of ‘plans’ and ‘solutions’ are out there, but most seem to address them one at a time, whereas they are interlocked, and the solution to all of them, from a political and economic standpoint would appear to be ‘more growth’. Politicians don’t get elected on an election slogan of “That’s all folks”. They admit, if pushed, to a little difficulty ahead, whereas the truth is that fossil fuel energy has allowed the planet to support perhaps 5 or 6 billion people more than there should be. Dr Tilley addresses the energy problem with the suggestion that we will be able to enter a gentle energy decline, with no idea of what those extra billions are going to eat. That, if I may say so is typical. Is there no concept at all of the energy needed to keep a city alive? Or what will happen when the energy to do that isn’t available?
    In 2001 the UK had a fuel delivery drivers strike, the government was given the stark warning that there was 3 days of food in the delivery pipeline.
    As energy goes into decline, (and it’s been on a peak plateau since 2005 exactly on cue 40 years after the peak production that Hubbert forecast in the 50s) those extra people will find they don’t have much of a future, and human nature being what it is, they won’t take very kindly to that.
    Humanity has evolved like any other species, to survive and thrive by filling every available niche that will support life, and we’ve done it rather well. Our infinite demands have now hit the wall of finite resources. Like any other unchecked species we have become a plague on our host. It may just be that climate change is the global sneeze that will get rid of us.

  5. Hi, Medieval, nice website. I enjoyed your post on asteroid mining. That one gives me a chuckle–billionaires like Schmidt, Page, and Gates are grasping at straws, and they have been conditioned to think that our economy runs on money, so all you need to do to achieve wondrous technological feats is to print or loan more money into being?

    Is there no concept at all of the energy needed to keep a city alive? On the issue of urban emergy basis, please check out the two papers at the link on the spatial distribution of energy at the link by Huang and Odum. Odum estimated that the eventual carrying capacity of the earth might be somewhere between 500 million and a billion, and I repeat, the emergy basis would be reduced by 70%. Dr. Tilley said nothing about the population reduction that happen as our resources decline, but he is very aware of the problem.

    Hubbert and Odum shared a podium at a Gordon conference in the early 1980s, I believe. I would have liked to have party to that conversation. And EROI is an early formulation of the concept of emergy, also by Odum. He began talking about the PWD in the late 1960s. Admittedly, it is getting very late to do something constructive about fixing our problems–but what we can do now is proactive adaptation. Active role modeling is a good start, and it channels anxiety into productive pathways. The changes will need to be self-organized and grass-roots based. I repeat, what’s your plan?

    Mary Logan

    1. Medieval makes good points about the impending descent and over population. However, in my defense i said nothing about popoulation. i agree with Dr. Logans projection that the earth could sustain 0.5 to 1.0 billion. My scenario assumed some number of people made it through the descent and raised the question of how their life would be intimately tied to the natural rhythm of renewables with electricity available. Based on Medieval’s monicker i assume they see a future with serfdom and royalty. i can’t imagine after centuries of revolution across the globe that citizens indoctrinated into democratic rule would allow reversion to such an inefficient state. but maybe i am missing the meaning of their name.
      the evolution of government–into democracy in the developed world–is a perfect example of self organization at work. the system will offer choices which will be selected for based on their ability to maximize total energy flow at multiple scales (Odum’s max empower).
      the future will have electricity for some form of global communication…maybe a scaled down internet without all the fluff of todays version. i dont think a medieval world can exist with educated citizens, personal firepower and a pseudo-internet.

    2. Mary Logan,
      Interesting that you say it will need to be self organized and grass-roots based. I agree. Have you seen this footnote in Holmgren’s Permaculture book? Note that he claims the primary difference between his approach and that of HT is strategic – bottom-up vs. top down:
      “The most recent book by Howard and Elizabeth Odum, A Prosperous Way Down, Principles and Policies (Wiley 2001), is a readable and timely explanation for the lay reader of the EMERGY concepts and implications of energy transition for the economy, society and culture. It updates their much earlier, easily accessible text Energy Basis for Man and Nature (McGraw-Hill 1976). Although I have never had any correspondence with the Odums, and the manuscript of this book [Permaculture: Principles & Pathways Beyond Sustainability] was largely complete before the publication of A Prosperous Way Down, the common understandings informing the two are clear. The strategic difference in our responses to the reality of transition is the Odums’ emphasis on top-down cultural and public policy change directed at a mainstream audience. Permaculture has historcally focused on pushing the boundaries of innovating change at the cultural fringe and putting in place real but modest models of living from nature’s abundance.”

      And speaking of Holmgren, he has an interesting concept of “Top Down (systems) thinking, with bottom up (grassroots) action. Though he does have a chart showing the middle class bulge will likely disappear after the end of fossil fuel based affluence, with a return to a more traditional energy hierarchy in society. He says “The trophic pyramid or energy hierarchy challenges some of our cherished beliefs about social equity, but we have a much better chance of building a humane and just transition to declining energy if we recognise the broader ecological ‘rules of the game.'”

      1. David, good question. Early on, in the 70s, HT was hopeful that public policy could be swayed–if we were proactive and could avoid going down so many blind alleys attempting non-net emergy resources with intelligent policies, then we could have both self-organization and reasonable top-down planning. Just think of what we could do with all of those resources being poured into ethanol, solarPV, oil shale, and fracked gas?

        But after Reagan’s new dawn in America, the US escalated its expansion off of debt and leveraged trade using the petrodollar and organizations such as the IMF and World Bank, thus leveraging global resources to put the US further into overshoot. We sidelined concerns about the environment and ideas of balance with nature, and began the pursuit of wealth. The feedback loops (regulatory capture and other mechanisms) are solidly in place, and top down change is no longer possible in this country, IMO, because of the super-circulation, but enlightened policy is possible on a smaller scale at local levels?

        But the top down policy was only a hope. The basis for HT’s ideas about hierarchy and energy is the maximum power principle, which explains why systems such as civilizations can self-organize out of the universal tendency towards entropy. Energy drives complexity by transformation through work into higher and higher hierarchies of complexity and order, reinforcing production through maximized available energy acquisition. The reformulation, Maximum (Em)Power, describes the maximum rate of emergy acquisition. “In time, through the process of trial and error, complex patterns of structure and processes have evolved…the successful ones surviving because they use materials and energies well in their own maintenance, and compete well with other patterns that chance interposes” (Odum). The maximum empower principle is a description of how self-organization develops over time, between scales, in complex systems, using energetic processes. New feedback loops will develop in descent, but that will take time. We could save so much time and wasted energy with some enlightened thinking?

        One of HT’s most common refrains, especially in group interactions, was, “let’s let it self-organize.” And he did just that. He took his frustration about being sidelined and poured them into efforts to refine a science that values nature on nature’s terms, knowing that that science would eventually be needed, if we came to our senses in time.

        Mary Logan

        1. Mary Logan, this is beautifully put! It seems that you’ve shown how chaos, order, complexity, self-organization, entropy, competition, mutual support and reciprocity, hierarchies, networks, chains, and webs all work together in ecosystems.

          1. Not me, but HT and a talented group of Emergy researchers who have recognized the importance of supply-based valuation of our economy that places the human economy in its proper place, supported by a hierarchy of nature. They’ve built have a rapidly growing body of work illustrating the emergy basis of all kinds of systems


  6. Having considered all the possible outcomes for an energy-depleted future, the nearest equivalent we have within a recent timeframe would appear to be ‘medieval’. While things might be worse than that, I don’t see it as better in the long term. While 21st century knowledge might make some differences, using that knowledge to any significant degree would require a corresponding leverage of the exogenous energy sources that have given us every level of development and prosperity throughout our history.
    Mankind is a unique species only in that we had the accident of learning how to make fire at will. Fire gave us leisure, leisure gave us time to think and exchange ideas; we learned to talk and write, dream up gods to explain natural phenomena, and plan creative homicide against tribes with different beliefs. Stealing their food and impregnating their women was essential to god’s purpose of course. Fire also provided the means to alter our environment and kill off competing species.
    With a few million in scattered tribes that wasn’t a problem.
    Then 10,000 years ago we hit on the idea of growing our energy close to home instead of chasing it. When the first farmers produced surplus food (energy) they used it to pay a soldier-caste to protect it, at that point energy in the form of food acquired an exchangeable value (we now call it money and still use it to buy energy). If the excess food supply was big enough to support enough soldiers, war, conquest and acquisition of energy sources of other tribes was both logical and inevitable. It scaled up precisely to our own era when our firemaking skills unleashed the steam engine; that effectively shone the energy of 150 million years of stored sunlight onto a living organism whose prime function is eating and procreation like everything else on this planet. It also gave motive power to our military machines and our fight for living space and survival suddenly got a whole lot easier, (and messier), but our instinct for survival stayed the same.
    The same forces drive the billionaire to make his second billion. He knows he doesn’t need it, but his primeval instincts make him invest in the tarsands in Alberta, or palm oil plantations in Malaysia.
    Just like the early farming tribes, his wealth buys him the necessary energy to acquire more; wrecking the environment is a secondary consideration.
    We have all been guilty of that to a greater or lesser degree, we all want a bigger house, car, more food and warmth, few accept we must consume finite energy to pay for it, or that it’s running short. Energy consumption has become the normality we will fight to preserve as we ignore energy depletion.
    Past history shows that civilization has the thinnest of veneers, and even when we had a planet full of ample resources for everyone, acquisitive conflict was been endemic to every society so depletion must bring warfare.
    We will not “go gentle into that good night” as Dylan Thomas so movingly puts it, or more to the point: “man is a tribal carnivore, not a gentle gardener”, to quote James Lovelock. That conflict will prevent any ‘easy decline’, we will fight over what’s left and by doing so destroy what’s left.
    Whatever our future, we cannot escape our need of energy in its most basic form: food. If we are to pass through a period of violent descent, that will leave food sources in the hands of a few who will defend it and with the right to distribute it among those willing to work for it. That is uncomfortably close to serfdom.

  7. Dave, I like the article and also the many comments it generated. I recently read an article in Human Ecology (Wang et al. 2010) called “Climate, Dissertification, and the Rise and Collapse of China’s Historical Dynasties” that examines historical fluctuations in flow-limited energy (primarily solar radiation and rainfall) in the ancient dynasties of China. They essentially argue that it was the occasional down-pulses of temperature and rainfall (and their effects on crop production) that brought down many of the great dynasties (not the usual courtly intrigues that historians love to write about). I’m making this point to emphasize the power of those flow-limited sources that you write about, and the sensitivity of human societies (especially highly intensive ones like the ancient Chinese states) to fluctuations in those flows. And to all that I want to add one point about the importance of slow-renewable storages like topsoil and timber to agrarian states of the past and maybe future. While I like the article by Wang et al., I think their story could be improved by considering the fluctuations in slow-renewables. I attempted to do so at my link below, that you might remember. I think also for the period of low-energy restoration that slow-renewables and their fluctuations will be additionally important considerations. I know you know this, but I wanted to draw it out some.

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