We Can Math : bev can recycling vs MPG (reprint)

by DeAnander Sun Jun 12th, 2005 at 04:09:45 PM EST

[This article was first published in 2005 on the European Tribune forum.]

The following question was raised in a discussion group online, under the general topic of SUVs and energy wastefulness: how much blame and dislike is it reasonable to attach to drivers of SUVs for their energy wastefulness, relative to other wasteful behaviours? One member said

The rest area near me has enough aluminum cans going into its dumpster to probably run a Hummer 50,000 miles per year on the amount of energy that’s being wasted by not recycling them.

or in other words, “people who don’t recycle their aluminium cans are at least as wasteful as people who drive Hummers.” Is this true? And what about the related question which immediately occurred to me: suppose you drive your Hummer to the recycling center to recycle some cans, how many cans must you carry to “save” or reclaim as much energy as you have spent by driving the Hummer to the recycling center? At what point is this a negative-sum exercise in absurdity?

Interesting questions, but how the devil can we figure out the answers? Show Me The Numbers!

These are typical of a whole set of questions that in an energy-literate society would be immediately obvious, but in an energy-illiterate (or energy-obfuscated) society are quite opaque. They set me off on a research project whose results are summarised below (many thanks to various members of carfree discussion list who helped with proofreading, math checking, etc). Food for thought. Here’s a table of approximate equivalencies — unit conversions, if you like — from which we may be able to draw some conclusions:

And now in English: 1122 people would have to recycle every single Al can they use in one year, to “save” enough energy to offset the energy consumption of driving one Hummer 50K miles. (And those people would have to recycle their cans without incurring any further energy costs, such as driving to the recycling centre or using an electric can-crusher).

If that one Hummer only drove the national average of 10K miles in one year, then “only” 1/5 as many people — 224 people — would have to dedicate their recycling lives to compensating for the gas consumption of this Hummer. As my yuppie neighbour memorably said, some years ago “Oh, it’s so nice that you’re conserving water — that means we can use more!”

You would have to recycle every Al can you use for 156 years, to produce the same “energy savings” benefit you would achieve by driving a 30 MPG car rather than a 10 MPG car for just one year. Since you won’t live 156 years, it appears you’ll need a friend or two to participate in this justification of a 10 MPG car :-)

The Hummer driver who drives 20 miles r.t. to recycle cans must carry at least 167 cans per trip to make the “savings” from the cans offset the energy cost of the trip — for a zero-sum game. The cyclist who eats organic and locally-grown food would have a much higher “profit margin” on this trip (not to mention the benefits of exercise and improved humour) for far fewer cans.

And we are still begging the question of why the H we “need” to manufacture 99 Billion cans per annum to contain watered-down sugar syrups with fizz, produced and marketed via an insanely wasteful web of long-haul transit. We wouldn’t need high-tech light containers for drinks if the drinks weren’t being hauled by air and truck several thousand miles before reaching their consumers… glass (also recyclable, at lower temps) would work fine if we weren’t obsessed with reducing freight weight and packing more cans in each cu ft of container space, or making the containers proof against the violent stresses of longhaul transit and repeated middleman handling. But I digress :-)

Back to the implications of the above numbers: The Hummer driver who thought better of it and decommissioned his Hummer in favour of a 30 MPG compact, would save more energy than he could ever achieve in 2 lifetimes of recycling cans, in just one year of average driving mileage (10,000 miles).

Or looked at another way: if a person could, by reason or wheedling or flattery or shaming or tax disincentives, be persuaded to trade in their 10 MPG Hummer for a 30 MPG compact — then the carping critic, nagging spouse or preachy enviro who persuaded them to take this step would have achieved 2 lifetimes’ worth of can recycling activity in energy savings, in just the first year of that Hummer’s inactivity, and the same savings for every year thereafter. That seems worth nagging about.

The person who refrains from driving their 30 MPG car for one year or 10,000 miles, choosing to walk or bike instead, achieves an energy savings in just that one year, equivalent to the average can-consumer recycling every single can they use, faithfully, for 74 years (or an average lifetime).

Likewise the person who persuades, cajoles, bribes, shames, begs or ridicules even one other person to stop driving their 30 MPG car and ride a bike or walk instead, has contributed to an energy savings in the first year that is equivalent to a 74-year lifetime of faithful recycling.

The lesson I draw from this is that it is very much worth our while to make every kind of outreach and effort to “uncool” gas guzzling SUVs and encourage at least a return to moderate gas frugality, and at best, an increased popularity of carfreedom. Each year of the difference between Hummer and subcompact or moped is worth 2 lifetimes of can recycling, and each year of the difference between subcompact and feet/bike is worth 1 recycling lifetime.

The choice of transport we make — its energy cost — seems to outweigh the importance of our recycling activity by about the ratio of 1 or 2 lifetimes to one year.

BTW, “recycled” Al cans are not made from 100 pct recycled alloy. Some virgin metal is also introduced into the process. So the “savings” is a reflection of the percentage of recycled material and the E-cost of resmelting it as opposed to the cost of refining virgin ore. But virgin ore is still dug and refined and smelted in the making of “recycled” cans.

Axiomatically, the savings accrued by not making 1 can will always be far larger than the savings accrued by making 1 can partly out of recycled metal.

Originally published at www.eurotrib.com.

Retired; ex-software engineer. Paleo-feminist. Sailor. Arduino tinkerer. Enviro. Libertarian Socialist (Anarcho-Syndicalist, kinda). Writer. Altermondialiste.