A false economy: looking at embodied energy

G Magazine

Where does the true cost of your purchases lie?

Australian money in wallet

There's more to it than money: embodied energy is important to consider when purchasing goods.

Credit: Martin Kingsley

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For those of us looking to be more environmentally responsible in our consumer activity, adding up the energy packaged in our purchases, a concept known as embodied energy, is an illuminating exercise.

You might be surprised at what you find when you start adding it up, because seemingly self-evident truths are frequently turned on their head.

But be warned, embodied energy is notoriously hard to calculate and often comes down to where you draw the boundaries on what it is that you're measuring.

Indeed, things often seem clouded in a fog of numbers and statistics. And the real world of dollars and cents starts looking a little unreal.

Plastic fantastic?

"Because many people don't have much of an idea of what goes into a material they often hold misconceptions on what its value is," says Zbigniew Stachurski, Director of the Centre for Science and Engineering of Materials at the Australian National University in Canberra.

"Plastic is a good example of this. Because most of us see plastic as being cheap, light and disposable, we think it doesn't take much to produce," he says.

"And yet plastic is derived from fossil fuels and if you consider the time and resources that go into finding and exploiting an oil well, and then transporting that oil to a place it can be processed, you'd be astounded at how much energy has been expended even before it starts getting turned into a recognisable plastic product."

"However," Stachurski says, "because energy has historically been cheap, this expense is largely ignored in the final cost of the product."

"That's where adding up embodied energy over the life cycle of a product can be quite illustrative of the true cost of that product if you're taking into account its impact on the environment. Traditionally that cost has been ignored or heavily discounted."

Life cycle what?

And this aspect of life cycle and what happens after you've used the product is critical as well, says Stachurski, because we often don't ascribe any cost to throwing something away.

"Of course, in reality, things don't dematerialise when you toss them out, there's a cost down the line for someone somewhere in disposing or recycling the materials that you're no longer using."

Embodied energy and life cycle analysis are well known engineering concepts, but to the wider public they're still somewhat new ideas.

It's important to appreciate the difference between embodied energy and operational energy. The first relates to what it takes to make and dispose of a material or a product.

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