Archive for March, 2009

Energy Hunter-Gatherers to Energy Agriculture?

March 24, 2009

Isaac Berzin (founder and creative vision behind GreenFuel Technologies in its early days, now a professor in Israel) once proposed an analogy that I thought was pretty interesting, and relevant in this time of uncertainty about our energy future, and so I report it here.

Isaac suggested that the way modern society has been using energy over the last century or more is akin to the way hunter-gatherers provided themselves with food in prehistoric times, and predicted that we will soon make a transition akin to the one that replaced hunter-gathering with agriculture – that we will begin growing our own energy in situ.  Now this obviously makes literal sense in the case of algae biofuel, where photosynthesis is actually doing the critical work.  But you don’t have to believe in the promise of algae biofuel (which is still very much in its infancy) or cellulosic ethanol (likewise) to appreciate the core insight.  I think the analogy also holds for other forms of renewable energy as well – we already get significant amounts of power from maintaining and operating our stationary, long-lived “wind farms”, and it’s not too hard to imagine an array of PV modules in the yard as a sort of  “kitchen energy garden”.  This stands in strong contrast to our present practice of nomadically scouring the global energy plain for rich herds of petroleum “food”, slaughtering, devouring and abandoning in sequence West Texas, the North Slope, the North Sea, and the Persian Gulf.

It seems to me that archaeological study of the prehistoric transition to (food) agriculture offers a dark cautionary note: recent research provides strong evidence that the size, strength, and health of humans actually took a dramatic step backwards with the transition to agriculture – see for instance this piece by Jared Diamond.  It occurred not because it was nutritionally superior (it wasn’t), but rather because primitive agriculture could support population densities sufficiently high to drive off the hunter-gatherer competition with their necessarily sparser numbers.  I don’t endorse his thesis (that the transition to agriculture was the worst mistake our species ever made), but the important point here is that the replacement of a mature hunter-gatherer technology with an immature agriculture technology was accompanied by a centuries-long transition period of acute suffering.  Once again, the transition seems to be occurring not because of inherent superiority or cost (renewable energy is an expensive pain in the butt) but for technical reasons – we’re just plain running short.  There’s further cause for concern: in the prehistoric case, the areal productivity of the new agricultural technology was truly improved relative to that of its predecessor (which was after all similarly dependent on sustainable solar “income”), while we are presently burning our fossil fuel “savings” at thousands of times the rate of formation.  Let us hope that this time we can somehow manage the coming transition without the stunted legs, rotten teeth, and epidemics of bubonic plague.

What happened to Tom Friedman?

March 10, 2009

I woke up Sunday morning to find that Mr. Flat Earth has had an epiphany:

What if the crisis of 2008 represents something much more fundamental than a deep recession? What if it’s telling us that the whole growth model we created over the last 50 years is simply unsustainable economically and ecologically and that 2008 was when we hit the wall — when Mother Nature and the market both said: “No more.”

When even the number one chearleader of global capitalism has finally realized that a finite planet can’t deliver an ever-increasing flow of crappy consumer goods, it’s time for a nice tall glass of cider.

Farming with horses?

March 1, 2009

For Christmas my sister got me a subscription to Small Farmer’s Journal, which is charmingly written by a character in Oregon name of Lynn Miller.  The quarterly magazine (large format, mostly black and white) contains tons of information about small farming, reprints of old articles on how to grow certain crops, and narratives from people who went back to the land and stayed there.  It took me a little while to realize that the editors have a serious soft spot for draft animals (the older issues carry the subtitle “featuring Practical Horse-farming”); in fact it seems to be a large part of the purpose.  The pages are peppered with photos of large hitches of beautiful horses plowing and harrowing soil, with a few oxen thrown in.  Now I have nothing against draft animals.  My uncle always has a team of oxen up in Mt. Vernon, and I freely admit that to a person given to romantic tendencies there is something fantastically stirring about these images of draft power.  And I am hardly one to throw stones, as a person who not so many years ago spent most of my spare time for over a year building a seventeen foot traditional wooden dory, which now sees the water once or twice a year.  And it means a lot to me that most of the wood in that boat was cut sustainably off of North End land by my father and mother, and that since we used copper rivets instead of iron nails the dory may well outlast me, given care.

All of that is by way of establishing my credentials as a person with tendencies toward picturesque anachronism. But little alarm bells go off in my brain when folks like me start promoting some anachronistic activity on grounds of practicality – to the extent of making claims that horse farming is cheaper or more practical than tractor farming – and when it begins to take on the dubious contortions of religion.  For instance, the Amish have a charming tradition of using draft animals and shunning power, but they also have a strong instinct for economic survival.  For a long time (until less than 100 years ago), it was reasonable to farm with horses and ground-driven implements – where the rotary power to run the mower or manure spreader or other implement came from the livestock, but via a rigid shaft attached to the wheels of the implement.  But as farms got bigger, horsepower could not provide enough power to drive the larger implements, and a curious contraption known as the power forecart has come into existence – a horse-drawn 2-wheel wagon with a seat and a gas or diesel engine, with the engine driving a PTO shaft and a 3 point hitch (and probably hydraulics for good measure).

Now, I have nothing against the Amish or power forecarts.  I just want us to be honest with ourselves, and say “We love working with horses and this chimerical horseflesh/motorized contraption allows us to get our farming done at a sufficient scale to be profitable while allowing us to work with the animals we love.”  Or maybe “This forecart system lets us strike a balance between economy and tradition that allows us to keep our children in farming and our social institutions intact.”  Or follow our not-so-conservative conservative rabbi friend, who might say “We use this forecart system not because it is practical, but precisely because its impracticality embodies and demonstrates our devotion to god.”  Those seem like honest, self-aware answers.  Similarly, I freely admit that my cider orchard is little more than an overgrown hobby, that I will never produce cider apples at less cost in time and money than I could buy cider, and that it would be a lot less work and more straightforward to hook my pedal-powered apple grinder up to a nice, quiet quarter-horse induction motor (hell, the flywheel already has a v-belt groove machined right in!)

So, no complaints here about anachronism, acknowledged honestly and with good humor.  But switching over to my engineering hat, my interest this morning is to try to understand whether draft livestock on small farms can and should be a part of a localized intensive agriculture future.  Out of familiarity, I’ll take the land the nascent orchard is planted on as an example – this is about 30 acres of land, but only 5-6 are cleared, and of that less than 1 acre is in any kind of active production.  By way of background, in earlier posts, I did a rough calculation suggesting that intensive agriculture would require at least one half acre per person to provide a well-balanced vegan diet.  This paper (which seems to be written by an intelligent, practical person) indicates that an average horse consumes about 4 tons of hay per year.  Most of the people in Small Farmer’s Journal seem to be using workhorses, and typically in teams of 2 or more.  A percheron being at least 50% heavier than a mill-run sporting horse (and putatively working much harder), we’d need to provide at least 6 tons of hay per year.  Yield for hay nationally appears to be around 2.5T/acre, and Maine being colder and less sunny than many places, probably 2T would be as much as you would want to assume.  So 3 acres of ground would need to be set aside to keep just one workhorse going – and it’s common to put several in a hitch to perform common farm tasks.  That’s not too surprising since even a small cat1 tractor is ~25 hp.  More than half the available land would need to be used to feed the workhorse, even though we would only need to use it every once in a while – and this is on a much bigger piece of property than many people doing local intensive agriculture will ever work.  (Eliot Coleman’s rule of thumb is that one person can tend around 2 acres maximum.)

So, it seems that the basic problem is that the quantity of land required to keep even one workhorse dwarfs the scale of a typical cottage farm.  Further, a family doing small-scale farming won’t need a horse all the time (I imagine most use is concentrated in spring and fall), but the horse will eat all that time. In contrast, a tractor only eats when you use it.  I’ve never worked with draft animals, but based on my experience doing small farm tasks with (and maintenance on) a 30-year old used diesel tractor, it is hard for me to see how draft power will be truly practical until fuel is well over an order of magnitude more expensive than it is now.  More than economics, though, the main issue is practicality.  I read somewhere that small farms taken as a whole have a -30% profit margin; that is small farmers farm out of love, and subsidize their farming with work off the farm.  Now, people who farm out of love are welcome to use whatever form of power they want, and god bless them, but my interest here is to understand whether on-farm horse power would make sense in a hypothetical future where people were operating small farms as a significant (though perhaps minority) share of family net revenue.  For many, maintaining a source of off-farm income is likely to conflict with optimal care, and a only a limited number of people will be willing to sign up for the twice-daily-without-fail routine of keeping livestock.  Even my parents (who once kept pigs, sheep, and goats) have whittled down to chickens, as the one type of livestock neighbors can be consistently found to tend (so that they can take a vacation).

One effect of the high baseline feed requirement of draft animals is that the economics improves substantially as utilization increases – that is, if you are going to have draft animals, it makes sense for them to be working much of the time.  So (again in a hypothetical future world where there were a lot more small farms), perhaps a more workable system would be to have a few teamsters in any given region, who hire out to a number of local farmers on a daily or hourly basis, perhaps partially in trade for hay and feed.  (The same thing could theoretically be arranged in cooperative hippie communes, should a scalable model ever arise for how to form and maintain them.)  But in a thought experiment comparing [guy plus two workhorses and tack] with [guy plus 20hp tractor], it’s hard seeing how the guy with the horses wins, again excepting the situation where fuel costs $100/gallon.