Vegetables, bones, and reliable power: humans vs machines

“One farmer says to me,” reported Thoreau, “you cannot live on vegetable food solely, for it furnishes nothing to make the bones with; and so he religiously devotes a part of his day to supplying himself with the raw material of bones; walking all the while he talks behind his oxen, which, with vegetable-made bones, jerk him and his lumbering plow along in spite of every obstacle.” Thoreau, as you can tell from the quote, was a bit of a snob, and perhaps was missing the farmer’s point, which may have been “if you want ME to grow your vegetables, then don’t lecture me on what ought to satisfy my stomach at mealtime.” But this quote, which I first encountered some time in the late 1960s in Bradford Angier’s How to Stay Alive in the Woods, always stuck with me. I hear similar claims today, though maybe it’s more excusable: so many of my Canadian contemporaries are so completely disconnected from both their food supply and the sheer amount of energy that goes into providing it that it shouldn’t be surprising to hear such claims.

Besides, those claims pale in sheer cockamamieness beside claims on what can power society. I have ranted and raved myself blue in the face in this blog about people who think solar energy can power our electrical grid. The vegetable power about which Thoreau waxes so poetic in the quote above is actually solar power. It comes to us humans by way of chemical reactions in our metabolism in which the reactants include chemical constituents in the food we eat, e.g. carbohydrates. As I pointed out in previous articles the energy released in those reactions is sufficient to give an average human being an average power output of roughly 100 watts.

Well, a typical toaster uses roughly 1,200 watts. To generate enough power to toast bread, that is what you would need to produce. I invite you to try outputting 1,200 watts for any length of time, let alone the two or so minutes it takes to toast bread.

I did four 500 meter sprint rows yesterday on a Concept 2 rower. Each one took roughly 1:50—roughly the amount of time it takes a toaster to make toast—and the average power output in each row was, according to the C2 display, 223 watts, 221 watts, 219 watts, and 218 watts. I was totally exhausted after that workout (mind you, after each row I did 20 pushups); each row session seemed harder than its predecessor.

This will teach you the true meaning of “watt.” Set distance to 500 meters, then see how quickly you can bring it to zero. If you are like me, it should take no more than a minute and fifty seconds. If so, congratulations. You produced enough power to run two 100-watt lightbulbs for a minute fifty.

This, which ironically is a machine that makes you work instead of doing work for you, will teach you the true meaning of “watt.” Set distance to 500 meters, then see how quickly you can bring it to zero. If you are like me, it should take no more than a minute and fifty seconds. If so, congratulations. You produced enough power to run two 100-watt lightbulbs for a minute fifty. How much effort did it take? Again, if you are like me, a lot. This is what 200 watts feels like.

In brief, four sub-two-minute rows, in which I put roughly 220 watts of power into the rower for each sub-two-minute session, just about did me in.

There is no way I could, on my own power, make toast. That applies to just about everything else I do. I could not on my own power run even a single 24-watt compact fluorescent light for all that long: if I were powering such a device with my own physical body then that is all I could do. Forget about powering my stove oven, which needs 2,100 watts. And totally forget about my biggest power demand, which is moving my two-and-a-half-ton car: to maintain a speed of 100 kilometers per hour my car’s drivetrain needs around 15,000 watts of power just in its crankshaft (and I am not even including the total energy release from the gasoline fuel, which is roughly five times what the crankshaft needs).

This is why humans invented machines in the first place. It is hard to do all the things we need to do.

It is also why, before humans had machines doing all this work, some of them had, like Thoreau’s farmer, animals. Others had slaves. Whether those slaves were fed with vegetables or meat didn’t really make much difference in their power output: it was on average the same 100 watts that it is today. Regardless of what a slaveowner fed his slave, as long as it was food and enough of it, the difference in power output between a high-performing slave and a low-performing one was maybe fifteen percent at most. A toaster requires a power increase of a whole order of magnitude beyond what a normal human can output.

Thoreau died in 1862, a year after the beginning of the American Civil War. That war, I might remind you, was, in the words of a commenter on this blog, “a war over whether machines labor for all or humans labor for a few.” The Civil War was perhaps the most violent manifestation of the political conflict that had swept the entire western world during the 1800s: the conflict over how humans ought to fulfil themselves during their short life on the surface of this planet. The triumph of machine power in that conflict gave many humans, more than ever before in history, an actual shot at fulfilment. It did not guarantee that the demands of the economic machine to which the Industrial Revolution gave rise were subordinate to human fulfilment—as Erich Fromm lamented in 1956, the reality appears to be just the opposite. But without machine power, there would be no shot at fulfilment. Most of us would be toiling in medieval drudgery.

Human minds had dreamt, since the beginning of time, of freedom. The greatest political minds had for centuries pondered how to organize societies so as to have freedom. But it was machines, powered by fuel at least a thousand times as powerful as us, that actually gave it to us.

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5 years ago

I invite you to try outputting 1,200 watts for any length of time, let alone the two or so minutes it takes to toast bread.

One summer some time ago I lived near the bottom of a tall bluff.  A road ran up the bluff, and as part of my exercise program I would ride my mountain bike up said bluff to the park at the top.  If I had any energy left I’d look around at the top (I rarely did).

My record time for this climb was about 25 minutes, which translates to a steady power of around 150-160 watts exerted against gravity (friction not included).  I could probably provide 1200 watts for a few seconds.

Andrew Jaremko
5 years ago

Steve – thanks for this post and analysis. There’s some directly relevant video from the BBC’s ‘Bang Goes the Theory’ show. For one episode, cyclists powered a home for a day: the Human Power Station. The full episode used to be available, but I couldn’t find it. I did find two segments, though.

The first is the Human Power Station Test : https://www.youtube.com/watch?v=7l_RbsLYCVA
including making toast.

The second is the biggest challenge: the shower head that heats water as the water passes through it. The 8.5 Kilowatt Power Shower:
https://www.youtube.com/watch?v=C93cL_zDVIM

And Steve – here’s an article I found relevant and I have to figure out how to apply:

The Best Way To Win an Argument

The problem is, the method requires Socratic engagement with people one at a time. Methods of persuasion en masse amount to demagoguery, argument by personality, and emotional/religious conversion rather than rational persuasion. The Monty Python crew got it right in the Life of Brian. Here’s the Think For Yourselves clip:
https://www.youtube.com/watch?v=QereR0CViMY

It is at this point that I heave a Charlie Brown sigh.

5 years ago

Gives me a new perspective whenever I’m hearing my daughter using a 1500 watt appliance for 3 minutes or so to evaporate water from her hair.

5 years ago
Reply to  Paul Kuster

Yeah, roughly 2 horsepower dissipated in a unit weighing maybe a pound.