Through the clouds of wishful thinking that too often make up what we are pleased to call a collective conversation on the subject of energy, a ray of common sense occasionally shines through. This week’s ray came by way of a study on the Earth’s thermodynamic balance, soon to be released in no less a scientific publication than the Proceedings of the Royal Society. The study found among other things that there’s a fairly modest upper limit to the amount of energy that wind farms can extract from the atmosphere without changing the climate.
So far, at least, the peak oil blogosphere hasn’t responded to this study at all. That’s not surprising, since the idea that renewable energy resources might also be subject to environmental limits is about as welcome in most alternative circles these days as a slug in a garden salad. These days, for many people who consider themselves environmentally conscious, a vision of giant wind turbines in serried ranks as far as the eye can see fills a pivotal emotional need; it allows them to pretend, at least to themselves, that it’s possible to support today’s extravagant lifestyles on renewable energy – to have our planet, one might say, and eat it too.
In the real world, things don’t work that way, but we’ve had a long vacation from having to deal with the real world. Three hundred years of ever-increasing production of fossil fuels have misled most of the population of the industrial world into thinking that it’s natural and normal to have as much cheap energy as you want and are willing to pay for. As petroleum production wobbles along a bumpy plateau and approaches the point of irreversible decline, and other fossil fuels move implacably toward their own peaks and declines, one of the prime necessities of sanity and survival involves unlearning the mental habits of the age of abundance, and coming to terms with the fact that all human activities are subject to ecological limits.
It’s as though we’re a bunch of children with very, very short memories, who wake up one morning to find that it’s Christmas Day and there are heaps of presents around the tree. Giddy with excitement, we open one package after another, revel in our shiny new toys, then delight in the holiday atmosphere of the rest of the day. As night falls, we doze off, thinking happily about how there will be another round of presents and another big meal the next day. Then the next day comes, and it’s not Christmas any more; search as we will, the area around the tree stubbornly refuses to yield any more presents, and if we strain our memories as far as they will reach, we might just remember that the other 364 days of the year follow different rules.
Especially in America, but not only in America, a great many people are basically sitting around on the day after Christmas, waiting for Santa Claus to show up with gigawatts of bright shiny new energy in his sack. The people who insist that we can keep our current lifestyles powered with giant wind farms or solar satellites or Bussard fusion reactors or free energy devices – thatt latter is what they’re calling perpetual motion machines these days, at least the last time I checked – are right in there with the folks who chant "Drill, baby, drill" in the fond belief that poking a hole somewhere in a continent that’s been more thoroughly prospected for oil than any other part of the Earth will somehow oblige the planet to fill ‘er up. I have too much respect for magic to dignify this sort of logic with the label of magical thinking; an initiate whose grasp of occult philosophy was that inept would be chucked out of any self-respecting magical lodge on the spot.
The realization that has to come is the realization that most current chatter about energy is trying desperately to avoid: that Santa isn’t bringing gigawatts or, if you prefer, that no law of nature guarantees us a steady supply of enough energy to maintain the fabulously extravagant habits of the recent past. Once people begin to grasp that the only meaningful answer to the question "What energy resources will allow us to keep the electricity grid running and cars on the road?" is "There aren’t any," it’s possible to ask a different question – "What energy resources will allow us to provide for the actual necessities and reasonable wants of human beings?" – and get a more useful answer.
That’s more or less the discussion I’ve been trying to further with the posts on energy here in recent months, in the course of surveying those ways of working with energy with which I have some personal experience—conservation first and foremost, but also homescale solar and wind power. There are also plenty of other other options that I haven’t worked with personally, and they also deserve to be brought into the discussion.
"Micro-hydro" and "mini-hydro," for example, are potentially options of great importance in the broad picture of a post-abundance energy future, but they’re not options I’ve explored personally. The "hydro" in each of these phrases, of course, is short for "hydroelectric;" micro-hydro is homescale hydroelectric power, usually produced by diverting a small amount of a stream or river on one’s property through a small turbine and using the latter to spin a generator. Back in the day there was a certain amount of work done with simple undershot waterwheels made from scrap metal, hooked up to truck alternators of the sort discussed in an earlier post on wind; I have no personal experience with how well these worked, but the concept may well be worth revisiting.
Mini-hydro is the next step up, hydroelectric power on the scale of a neighborhood or a rural town. Unlike what I suppose would have to be called mega-hydro, this doesn’t require damming up whole river basins, devastating fish runs, and the like; a small portion of a river’s flow or a small and steep stream provide the water, and the result under most circumstances is a supply of sustainably generated electricity that doesn’t suffer from the intermittency of sun and wind. Of course it depends on having the right kind of water resource close by your community, and that’s a good deal more common in some areas than others; it also requires a good deal more investment up front; but if you can get past those two obstacles, it’s hard to think of a better option.
Small amounts of electricity can be generated in a variety of other ways. Still, one of the great lessons that has to be grasped is that the thermodynamic costs of turning some other form of energy into electricity, and then turning the electricity back into some other form of energy such as rotary motion or heat, can be ignored only if you’ve got a half billion years or so of stored sunlight to burn. There are situations where those losses are worth accepting, but not that many of them, and if you can leave the energy in its original form and not take it through the detour into electricity, you’re usually better off.
Methane is an example. Methane production from manure on a small scale is a going concern in quite a few corners of the Third World; you need more raw material than a single human family will produce to get a worthwhile amount of gas, but small farms with livestock yield enough manure to keep a small kitchen stove fueled on this very renewable form of natural gas. (The residue still makes excellent raw material for compost, since only the carbon and hydrogen are involved in methane production; the nitrogen, phosphorus, potassium, and other plant nutrients come through the process untouched.) Since cooking fuel is higher on the list of basic human necessities than most things you can do with modest amounts of electricity, this is probably the best use for the technology.
Flatulence jokes aside, I don’t have any personal experience with small-scale methane production. Wood heat, on the other hand, is a technology I’ve worked with, and it’s probably going to be a major factor in the energy mix in North America in the future. It’s a simple, robust technology that works very well on the home scale – in fact, it’s not too easy to use it on any larger scale – and many wood stoves come with what’s called a waterback, which uses heat from the stove to heat domestic hot water. (Combine solar water heaters with a cooking stove equipped with a waterback, and you’ve basically got your hot water needs covered year round.) The problem here is that wood heat is a major cause of deforestation worldwide; whether or not too much windpower can mess with the climate, as the study referenced earlier in this post suggests, it’s a hard fact that too much harvesting of wood has devastated ecosystems over much of the world and caused a range of nasty blowbacks affecting human as well as biotic communities.
There’s at least one way around that problem, though it needs to be implemented soon and on a large scale A very old technique called coppicing allows for intensive production of firewood off a fairly small acreage. The trick to coppicing is that quite a few tree species, when cut down, produce several new shoots from the stump; these grow much more rapidly than the original tree, since they have their root system already well in place. When the shoots get to convenient firewood size, the coppicer cuts them again, and yet another set of shoots come up to repeat the process. I’ve dabbled in coppicing – the vine maple of the Pacific Northwest, which grows like a weed and produces decent firewood, made that easy enough, and other regions have their own equivalents. As other fuels run short, the owner of a few acres who uses it for coppicing and sells dry wood nicely sized for wood stoves may have a steady income, or at least a perennial source of barter, on his or her hands.
Biofuels such as ethanol and vegetable oils are another source of heat energy that will probably see a great deal of use in the future, though here again the limits on production are not always recognized. In a world with seven billion mouths to feed and an agricultural system at least as dependent on fossil fuels as any other part of industrial civilization, diverting any substantial portion of farmland from growing food to producing biofuels risks a substantial political backlash. I wonder how many of the proponents of biofuels production have thought through the consequences of a future in which the hazards of driving might just include being stopped by makeshift barricades and torn to pieces by an impoverished mob that is all too aware that every drop of ethanol or biodiesel in the tank represents food taken from the mouths of their children.
Biofuels are likely to play some role in the early stages of the end of the age of abundance, then, but thereafter, at least until the world’s human population and post-petroleum agriculture have settled down into some sort of equilibrium, it’s unlikely that this role will be very extensive. Later on, it’s anyone’s guess, and the answer will be up to the people of the twenty-fourth century and onward, not us.
Methane, wood, and sunlight, then, will probably account for the great majority of heat energy in common use in the centuries immediately ahead of us. What about mechanical energy? The breakthrough that launched the industrial revolution was the discovery that heat from burning coal could be turned into mechanical energy by way of a steam engine, and much of what sets our civilization apart from other civilizations in history is precisely the ability to put almost unimaginable amounts of mechanical energy to work. If a car with a 100-horsepower engine literally had to be pulled by a hundred horses, for example, and each of those horses required the care and feeding that horses do, the number of such cars on the roads would be a very small fraction of the present total.
There are good reasons, some historical and some pragmatic, to think that the major source of mechanical energy in the post-abundance future will be what it was in the pre-abundance past, that is, human and animal muscle, amplified by a variety of clever tools. If anything, some of the more ingenious inventions of the last few centuries make muscle power even more useful now, and in the centuries ahead of us, than it was before the first steam engine hissed and groaned its way into a new age of the world. The extraordinary efficiency with which a bicycle converts muscular effort into movement is a case in point. The relatively simple metallurgy and engineering needed to build a bicycle is very likely to survive into the far future, or to be reinvented after some more or less brief interval, and the sheer value of a technology that can move people and supplies a hundred miles a day on decent roads will hardly be lost on our descendants. It’s far from unlikely, for example, that wars will be won in the post-petroleum era by those nations that have the common sense to equip their infantry with bicycle transport.
More generally, the invention of really effective gears may turn out to be one of the nineteenth century’s great contributions to the future. The Roman world had some very complex machines using cogs and gears, but the designs used at that time did a poor job of transmitting power; gearing systems originally evolved in the late Middle Ages for clockwork underwent dramatic changes once steam power created the need to transfer mechanical motion as efficiently as possible from place to place and from one direction to another. Once invented, effective gears found their way back down the technological pyramid to the realm of hand tools; anyone who has ever compared beating egg whites with a spoon to doing so with a hand-cranked beater will have a very clear idea of the difference in effort that such simple mechanical devices make possible.
That difference may not seem like much in comparison to the gargantuan achievements of current fossil fuel-powered technology, or the even more grandiose fantasies served up by a good many of those who insist that the end of the age of petroleum must, by some kind of technological equivalent of manifest destiny, usher in the beginning of the age of some even more titanic energy resource. Still, if these claims amount to sitting around the chimney on December 26 waiting for Santa’s boots to appear – and I think a very good case can be made for the comparison – it’s past time to shelve the fantasies of limitless energy and the hubris that goes with them, and start paying attention to the tools, technologies, and modest but real energy sources that can actually have a positive impact on human existence in an age when only natural phenomena have gigawatts at their disposal any more.