Powering Happy Hippies?

A couple of recent things have converged in my mind in the last week or two, leading me to ponder more of the quantitative aspects of this whole sustainability thing. The first of these was spending the weekend at Jeff Poppen's solstice festival, and contemplating his views on society, economy, and agriculture. As he lays out in this interview, he envisions a system that I have kind of dubbed in my head "happy hippie feudalism." I don't mean this at all as an insult; in his version the "serfs" are actually totally free agents who live a quite pleasant life. Part of his thesis is that since a farm can feed 50-100 people, why do the other 49-99 folks need to be toiling away in the capitalist economy? He envisions them as just hanging out most of the time, enjoying life, strumming guitars, and then all pitching in at the times when a lot of person-power is needed at once. There is a whole lot more to his philosophy and practice, including strongly anti-capitalist views, a belief that when you sell produce and turn it in to a commodity you destroy farming, and an adamant position that a farm MUST have animals (preferably cattle) on it to complete its functions. But since we were there on one of his "everybody come hang out, eat good food, and strum guitars" festival weekends, this is the part I was pondering the most. I was in particular contemplating whether his fundamental thesis is really viable -- can you support 50-100 people on 300 acres of land in a sustainable and happy way? His vision actually seems like a quite nice way to live for all involved, if it is possible.

I suspected that he might be underestimating the extent to which his lifestyle and productivity were supported by the fossil fuel system that holds up pretty much everything in modern life, including most contemporary organic agriculture. I saw plenty of diesel- and gasoline powered equipment, and fields that looked to have been plowed by tractors, not horses or oxen. And his produce is delivered by car and truck, even if he is giving a lot of it away for free. I never had a chance to talk to him directly about this (very hard to corner a host when he has 1000 house guests; I was lucky to get that one photo I posted last week!). So I wondered if, in the absence of these subsidies, the lifestyle of the 50-100 happy hangers-on would actually be as relaxed as he describes.

The second thing was coming across the work of Axel Kleidon of the Max Planck Institute. He does what I have long thought ecosystem ecologists needed to do (if they actually understood thermodynamics, which most don't) -- he examines the total earth system from a complete thermodynamic perspective of energy, entropy, and free energy, and looks at the disequilibrium power generation of the total earth system. This stuff is not fringe; it may be controversial (especially among those who dislike his conclusions) but it is based on sound, solid scientific principles. There is a summary of a presentation he gave in August, 2010 available online.

One of his interesting conclusions is that the earth system on average generates about 2 W/m² of useable (free energy) power. This is in contrast to about 1000 W/m² of incoming solar radiation. And, he points out, that this 2 W/m² is already being used to drive the earth system processes on which the biosphere depends -- the climate system, soil processes, the hydrologic cycle, etc. Any of this power that we divert for human uses, such as wind or hydropower, is power taken away from the rest of the earth system. In other words, less power available to drive all those "free" processes that we take for granted but without which we cannot live. He is lately catching flack from renewable energy proponents for suggesting that their favored energy sources may be more limited and have more unforseeable impacts upon the earth system than are widely appreciated.

So I put Kleidon and Poppen together, and wondered whether those 300 acres of the earth system can really power the needs of 100 people. Using the 2 W/m² rule of thumb, those 300 acres (120 ha) generate 2.4 MW of power. A person's basic biological needs are about 100 W (yes, you and a 100 W light bulb are about equivalent). So just to give them the calories to stay alive, those 300 acres could drive 24,000 people. A ridiculous conclusion, of course, since people need far more than just their basic calorie intake, and there is no way to extract all that power from the earth system without destroying it (which is one of Kleidon's major points). But, that still is a whole lot of slack, and it does not seem at all unreasonable that there is way more than enough power from those 300 acres to keep 50-100 people comfortably fed, clothed, housed, and heated without disrupting the earth system. So maybe Jeff is really on to something, even without the diesel tractors.

Going at this from a more traditional ecological perspective, how does it work out? Well, typical annual ecosystem net primary productivity (NPP) of land such as this is in the ballpark of 0.4 W/m², which works out to about 480 kW for the 300 acre farm. Those 100 happy hippies need 10 kW of food to stay alive. A very rough rule of thumb is that agriculture can convert about 10% of NPP to human food. So the 100 happy hippies only need about 20% of those 300 acres in managed agriculture to stay fed. That is definitely in the ballpark, I would think, of the size of the human footprint on the landscape that could be considered sustainable and compatible with an intact ecosystem and habitat mosaic. It might be better at 10%, in which case we are still feeding 50 happy hippies without any fossil fuel inputs. It is harder to say how much labor would be required to keep everyone fed, clothed, and housed, and if this would be low enough to allow for enough hanging out and guitar strumming for the hippies to truly be happy. But it does look like Jeff might not actally be off the mark; even without the fossil fuels his vision might well be feasible.

It certainly is vastly more feasible than many present-day visions of "sustainable green-energy futures" with a hydrogen-powered vehicle in every garage and a state of the art wind turbine on every roof where people live in energy efficient suburban comfort twiddling away on their iPads.