HOW GREEN IS THE U.S. CENT?

Most people know that pennies cost the government more to make than they're worth, even after the U.S. Mint switched to using mostly zinc in 1982. They may not know that making all those pennies has a serious environmental impact, from raw ore, to smelter, to mint, and then to banks before finally being dropped on the street or dumped into a coin kiosk or a fountain.

So with those costs also in mind, is it possible to make the penny greener?

Christina Cogdell, an associate professor of design at the University of California Davis, asks her undergraduate students to parse out each material comprising a particular product, all the way from raw material to burial. Two years ago, three of her students chose the penny. Christine Knobel, Nicole Tan and Darin Reyes spent a semester analyzing the information they could find to make an assessment of the penny's ecological footprint. Their conclusion was the true cost of making a penny adds up to much more than 1.43 cents, or what the Mint reports it cost to produce a one-cent coin last year, though they were not able to individually parse out the incremental cost per coin of mining, smelting, minting and trucking the coins—all energy intensive processes. “We were surprised about the lack of information,” said Knobel. “We weren't able to find out anything more detailed.”

To be fair, the current production cost is down from the 1.66 cents it cost in 2014, and the continuation of a years-long trend and efforts by the Mint to increase efficiency as well as sustainability.

The Mint itself has tried to find out if making coins, including the penny, out of different metals might make them cheaper (and maybe greener) to produce, but it concluded, that for the penny, “there are no alternative metal compositions that reduce the manufacturing unit cost of the penny below its face value,” according to a 2014 report to Congress.

Each Mint facility conducts monthly environmental compliance audits and aims to reduce direct emissions by 33 percent by 2020. The Denver Mint is already 100 percent wind-powered, and the power-hungry stamping presses now have a sleep mode to reduce power consumption when not in use.

Copper mines, located mostly in Arizona, tend to be of the open-pit variety, which allows more substances to be released. Zinc mines can be open or closed; Red Dog Mine, in Alaska and the country's largest, is an open pit mine, and has been embroiled for years in water pollution and toxic waste fights. Much of the rest of the country's zinc is produced in Tennessee, whose emissions are limited by virtue of being underground.

Here's an idea of the torture zinc must go through before it is pure enough to be lacquered with copper and punched into a coin. Mining involves blasting and chipping zinc-containing sphalerite ores away from the surrounding limestone, then crushing and processing the ores in chemical baths that separate the zinc from other minerals. At the smelter, raw zinc is roasted to remove sulfides, then sent through a leaching and purification process.

The main byproducts of this process include sulfuric acid, which is collected for resale, and sulfur dioxide, which can cause acute respiratory distress. Mercury is another impurity removed during this process. Nyrstar's operations, both at the mining and refining levels, are well under state and federal limits set for releases of other toxins including cadmium and lead, though the company was fined once in 2009 for a release of cadmium into the Cumberland River in excess of permitted release limits.

“After doing the research, it became clear that the penny isn't needed,” she said. “If the Mint is trying to reduce energy, why not reduce it by a whole coin? That would be a huge step in the right direction. I don't think it's going to be that big of a deal.”

To read the complete article, see:
How Much Does it Really Cost (the Planet) to Make a Penny? (www.smithsonianmag.com/science-nature/penny-environmental-disaster-180959032/)

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