Tech sector’s water footprint

When it comes to calculating water footprints, the tech sector gets something of a free pass. And it’s easy to see why. Crop production is responsible for about 85% of all water use, and anything made from those crops will use even more. The amount of water that goes into the making of a cotton T-shirt, for example, is 2000 liters. The water footprint of a microchip? 32 liters.
Biofuels are the clear loser in the water footprinting game. A recent report from UNESCO’s Institute for Water Education concluded that you would get the same amount of energy if you produced it from biomass in Brazil, requiring 15,972 gallons of water, as you would from producing crude oil with 262 gallons of water. For a breakdown of ethanol plants and their daily water usage across the United States, check out this nice map.

But people don’t talk much about the water consumption habits of nuclear plants or semiconductor manufacturers, which can use between 1 million and 2 million gallons of water each day quite as much as they should. That’s why I was delighted to come across this well-written Wired story, which covers the water usage of an Intel campus in Arizona.

Here’s a condensed version: Silicon wafers are rinsed several dozen times during their fabrication, which quickly adds up to 2 million gallons a day at that Intel facility. Before the water touches a wafer, however, it’s pumped through several filters to remove all mineral impurities, so that none of those imperfections touch the silicon. Once the water is used to rinse the chips, some of it is collected and sent to other parts of the campus—apparently including air scrubbers, cooling towers, and parking-lot landscaping. A reverse-osmosis plant in town, built by Intel, takes 1.5 million gallons of the wastewater and desalinates it to get it up to drinking water standards for local residents. Though the desalination plant was probably the wisest thing Intel could have done with its wastewater, both ecologically and politically, there is a downside. Pumping all that water around town and recycling it to the degree that Intel needs requires an incredible amount of energy—which comes from the nearby nuclear plant, which apparently uses 20 billion gallons of water a year. And did I mention this is all built in a desert? Sigh.

But even small and dinky technologies, like lightbulbs, rely on water for their power supply. I’ll leave you with one more mind-blowing statistic: a recent study by researchers at Virginia Polytechnic calculated that powering a 60-watt incandescent bulb for 12 hours a day for a year requires between 3,000 and 6,000 gallons of water.

Perhaps we’re at the cusp of a new phase, one in which water neutrality begins to become as salient in public discussions as carbon neutrality (not that we’ve aced that one…). At least one company, or perhaps only one company, has picked up the challenge. Last year, Coca-Cola announced a goal to beat out all its peer corporations in efficient water usage by the end of 2008, and to return all its water to the environment in usable form by 2010.


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