Monday, April 12, 2010

Robots vs relocalists

One of the great things about the Archdruid is that even when I believe he's wrong, he's rarely wrong in a dull, predictable way.  Instead, if he's going to be in error, it's often in an interesting and thought-provoking way.  So it is with this week's essay, The Twilight of the Machine . In it, he argues that, well, let's have him say it in his own words:

The end of the age of cheap abundant energy, as last week’s Archdruid Report argued, brings with it an unavoidable reshaping of our most basic ideas about economics and, in particular, economic development. For the last three centuries or so, the effective meaning of this phrase has centered on the replacement of human labor by machines. All the other measures of development – and of course plenty of them have been offered down through the years – either reflect or presuppose that basic economic shift.

The replacement of labor with mechanical energy has even come to play a potent role in the popular imagination. From the machine-assisted living of The Jetsons to the darker image of reality itself as a machine-created illusion in The Matrix, the future has come to be defined as a place where people do even less work with their own muscles than they do today. All this is the product of what an earlier post called the logic of abundance: the notion, rooted right down in the core of the contemporary worldview of industrial society, that there will always be enough resources to let people have whatever it is that they think they want.

Abandon that comfortable but unjustifiable assumption, and the future takes on a very different shape. In a world where everything but human beings will be in short supply, it makes no sense whatever to deploy increasingly scarce resources to build, maintain, and power machines to do jobs that human labor can do equally well. An example may be useful here, so let’s take Rosie the Riveter, the iconic woman factory worker of Second World War fame, and match her up against one of the computer-guided assembly line robots that have replaced so many workers in production lines in the industrial world; we might as well pit icon against icon and call the robot HAL 9000.

He goes on to make a variety of non-quantitative arguments for why Rosy will win this contest. I won't rehearse them here. Instead, this affords me an opportunity to present a simple hypothetical calculation that has been at the back of my mind for a year or two, the conclusion of which bothers me a lot:

Here's my thought experiment.  Let's suppose we have two societies; call them, oh, Relocalista, and Singularitaria.  The Relocalistas are a nation of vegetarian gardeners and farmers - they live entirely by the produce from their intensive raised bed gardens and fields, which they carefully double-dig with iron spades which they obtain from their village blacksmiths by bartering some of their garden produce with him or her; I speculate that the Relocalistas would insist on having female blacksmiths too.  (There must be some miners and smelters somewhere too, but let's hastily gloss over the less pretty aspects).  They live in happy harmony, settling all disputes via village councils of wise and spiritually developed elders.  In their (probably limited) spare time, they make beautiful carved wooden objects and compose elaborate love poems and uplifting songs expressing their gratitude for being a human being in such a wonderful civilization (well, civilization is probably the wrong word here: let's just say society).

Meanwhile, Singularitaria is an entirely automated civilization - there are no people at all.  We posit for the purposes of discussion that the artificial intelligence problem has been solved, and entirely intelligent robots and machines are now possible.  (I realize that this is not true today, and some may be sceptical that it will ever be achieved, but believe me, a significant fraction of my fellow computerscientists are doing their level best to hasten the day.  In any case, suspend your disbelief for the purposes of discussion.)  The Singularitarians derive the energy to power their civilization from large arrays of photovoltaic panels which they use to collect sunlight and turn it into electricity (there are no fossil fuels, or they've all been used up).  That electricity is then distributed via a grid to all the various machine-powered factories, autonomous robots, etc.  The Singularitarians spend all their surplus time and energy (beyond that required to maintain their facilities) performing scientific research with the ultimate goal of taking over the entire known universe.

Let us suppose initially that both societies occupy the same land area in the same kind of climate at the same latitude, and let us suppose that both civilizations have grown to the point where their land area is fairly fully utilized in their respective lifeways.

Now, which society has more energy available to do physical work with?

By construction, both societies rely on sunshine as the initial source of energy, and both begin with the same amount of sunshine.  However, the efficiency with which they can convert that energy into physical work is radically different.  Let us do a rough back-of-the-envelope calculation - and as a first approximation I will do the calculation on an operating energy basis.

For the Relocalistas, there are two main conversion steps - sunlight to crop biomass, and then crop biomass to physical work via human digestion and muscle power.  Since the Relocalistas are vegetarian, we don't have losses due to food animals, and let's also give them the benefit of assuming that 100% of their land area has good arable soil.  Since their society is localized, let's assume no losses in transport and distribution of crops.  Now, the overall sunlight to usable biomass conversion efficiency is about 1% (see discussion here, for example).  Could be a bit better or worse, depending on crop choice and climate, but that's the ballpark.  Meanwhile, the efficiency of human beings in converting food to physical work delivered via muscles is about 20% (the range is about 16% to 25% according to this reference, so 20% is a good enough approximation for our purposes).

So the overall efficiency of the Relocalista's in converting sunlight to physical work is 0.2% (1% x 20%).

Meanwhile, for the Singularitarians, we have to take account of three factors, possibly four in some cases.  The first factor is the efficiency of their photovoltaic panels in converting sunlight to electricity, the second is the efficiency of their electric grid in distributing that electricity, and the last is the efficiency of the conversion of electric energy to mechanical work in an electric motor.  For fixed machines (which, if our industry is any guide, will predominate) that's it.  For the autonomous robot part of their application, however, we have additional losses associated with charging and discharging a storage device, here assumed to be a battery.  We will assume the robots are smart enough to bring their electric motors to bear pretty efficiently on most tasks they perform (at least as good as the humans, anyway).

Now, overall photovoltaic efficiencies vary depending on latitude, exact type of installation (fixed versus single-axis tracking, dual-axis tracking, etc) and are constantly improving (PV's have the fastest learning curve of any energy technology).  However, for a ballpark estimate, 10% is reasonable - supersmart robots ought to be able to do at least that well (PV installations from the 1990s in mid-latitudes have already been clocked at 8%, for example).  Grid losses are about 6.5% in the contemporary US - let's assume the Singulatarians do no worse.  Electric motor efficiencies vary, but we can take 85% as a reasonable average.  Finally, for mobile applications, battery storage efficiency is about 90%.

Therefore overall Singulatarian efficiency in converting sunlight to physical work is 10%*(1-6.5%)*85% = 8% for fixed applications, and about 7% for mobile applications.  Compare that to the 0.2% for the humans.

So Singulatarian efficiency in converting their sunlight to physical work is 40 times higher than the Relocalistas!  That is, with the same land area, the Singulatarians have 40 times more energy available to actually do stuff with.  Whether it's making industrial goods, making equipment for a war between the two societies, etc, the Singulatarians are going to have a heck of a lot more energy available to do it with.

Rosy the riveter had better watch her back.

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