BY SAUL GRIFFITH
The Power of Things
Recently I have been preoccupied with pretty Do I count the air miles against me personally or
much only one thing, and I think it is genuinely my company? Do I count half of the car miles bethe challenge of our times: energy and the cause I generally travel with someone else? Are the
environment. In engaging with this issue, you have house utilities equally shared by me and my partner,
to think about how we harness energy (energy isn’t or does she get more because of her penchant for
created, but is instead converted to different forms), turning up the heat?
how we use power, and how we affect the environ- Where it gets really difficult, however, is in the
ment. I’ve done a lot of calculations of humanity’s objects that I consume. My computer took energy
energy use, and how we might make renewable to make, as did my clothes and my bicycles and my
energy technologies that can meet that challenge, DVD cases and furniture. But no simple calculations
but it’s a fairly impersonal analysis. for those yield a satisfying answer. So I looked in
To make it more immediate, I set about under- detail at the energy consumption of a simple drink.
standing my own power consumption. All of it. For irony’s sake, I chose an energy drink, but the
It turns out that this is a tremendously difficult calculation is reasonably applicable to any plastic
project, even if you have a rather large resource bottled beverage. As I looked at the numbers, it
of tools and information available to you. was interesting to me that the drink already had an
The easy pieces are those that are de facto energy label, shown here, described as “nutrition
measured for you (my values in brackets): facts.” This energy label is for the chemical energy
contained in the bottle that my body can convert to
mechanical energy to do work, like riding my bike
to the office. So I took the liberty of calculating the
energy footprint of that bottle, in reasonable detail,
and I summarized the results in an alternative bottle
label called “consumption facts.”
Let’s think about how one would go about estimating the energy consumption of one bottle.
Plane travel miles [ 6,375 watts, 110,000 miles]
I can check all my plane tickets for a given year,
use an assumption of plane fuel consumption (like
1.4MJ/km), and average that energy over the year
to get a measure of the amount of power I’m using
all the time.
Car travel miles [ 1,491 watts, 10,000 miles]
I can keep track of my odometers in the various cars
that I drive and get an accurate number of miles,
and by tracking fuel consumption over a number
of tankfuls, I have an accurate estimate.
Home electricity use [ 135 watts]
My home electricity use is conveniently reported to
me by Pacific Gas & Electric in the form of my bill,
so I have accurate year-round data for this.
Home gas use [597 watts]
PG&E also gives me my gas consumption in a bill.
I can convert from therms to watts.
I fly a lot. I don’t drive much — when I do, it’s
mostly in a hybrid. I have a small house. Your values
will probably be different, but not grossly so. These
simple numbers are not, in fact, perfectly simple.
1. There’s the energy embodied in the materials.
Embodied energy is a measure of the energy
required to extract, purify, mix, and make the raw
material. It is well calculated for many products.
I’d have high confidence in this number.
2. There’s the energy consumed in the
transportation of the object to us.
The energy consumed in transportation is a little
more difficult. How many miles did it travel? How
efficient was the truck/train/airplane used to
transport it? For this example, I assumed a 200-mile
travel distance and an average 8mpg truck fully
loaded with full energy drink bottles.
3. There’s the energy used in manufacturing it.
The energy used in manufacturing is a little tricky
for me to calculate. I’d like to divide the number of
24 Make: Volume 14