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Bench-Pressing India: The Real Cost of Your Daily Energy

Tuesday, May 17, 2011

Ahhh...a nice hot shower in the morning! Notwithstanding my mother's admirably spartan cold showers, I think this is the definition of "civilization". (Not surprisingly, my mother is also fond of "ice swimming"; I just have visions of the thermal shock of such a "polar plunge" making me bob back to the surface as a blue cadaver.) Anyway, shekel-wise, a hot shower costs less than a Looney.

So what’s the real cost of your morning shower?

But "cost" is a relative thing. And water is an amazing substance. Let's start with water. I think it's really cool that at least some of the water in the Earth's oceans may have come from extraterrestrial sources, e.g., protoplanets in the outer asteroid belt plunging to Earth early in its history. But more relevant to this blog is the fact that water has a high heat capacity. This means it takes a lot of energy to heat a litre of water just a little bit. And it releases a lot of energy when it cools just a little bit. Considering the vastness of the Earth’s oceans, this has a strong moderating effect on weather and climate, and makes life as we know it possible.

One shower could accelerate your car to 50 km/h…a hundred times…

Now back to cost being a relative thing. The amount of energy to heat my morning shower water is enough to accelerate my car from 0 to 50 km/h not once, not twice, but about one hundred times. Or repeatedly bench press 180 lbs at a rate of once per second for eight hours. That's a tough work day. (If I had to push my car up to city-speed this many times, or do that many bench presses, I think I’d need a shower after that.)

Canadians consume the energy equivalent of 70 showers a day

From this perspective, it strikes me how cheap energy is. It's remarkable that the things we do every day—and take for granted—don't cost a whole lot more, shekel-wise. Based on total energy per capita, Canadians consume about 70 showers-worth of energy each day. Considering that the average person can perform continuous manual labour at a rate of 60 Watts for an 8 hour working day, that's equivalent to well over 500 people in the "salt mines". Just for you! (This is assuming you're a Canadian, or from the U.S. It's only about 10 people if you're from Bangladesh.)

That's equivalent to 500 people labouring daily, just for you!

Modern technology and infrastructure make our voracious energy appetite almost invisible. The incredible labour-savings they afford is both astonishing and frightening. It’s gotta be costing someone, or something. It seems to me that the number 500 is worth contemplating.

Scaling up to the whole world, the total human energy consumption per year is roughly equivalent to Atlas bench pressing the Indian subcontinent by about 10 cm once per year. I can imagine him using a whole ocean of water for his shower….A spartan shower, to be sure—but at least one made slightly more civilized by global warming.


Written by: Richard Epp

Richard Epp has a Masters degree in electrical engineering and a PhD in theoretical physics from the University of Manitoba. He held postdoctoral research positions around the world working in general relativity before becoming Scientific Outreach Manager at Perimeter Institute for Theoretical Physics.