Technology News - October 20, 2004

Calculating computing’s environmental cost

The life-cycle costs of personal computers (PCs) are surprisingly high, according to the most detailed analysis yet conducted, which was published on ES&T’s Research ASAP website this week (es035152j). The determination that the “materials intensity” of computer manufacturing is 10 times higher than that of automobiles or refrigerators is particularly alarming because computers have such short useful lifetimes, according to the study’s author, Eric Williams of the United Nations University (UNU).

Williams found that manufacturing, using, and disposing of one desktop computer with a Pentium III processor and a 17-inch cathode ray tube (CRT) monitor uses at least 260 kilograms of fossil fuels and 6400 megajoules of energy.

Although Williams is not the first researcher to use life-cycle analysis to evaluate the materials and energy involved in producing computers, he contends that his study overcomes four weaknesses in previous studies: Not all of the data in the new study are confidential, so critical evaluation of underlying assumptions is possible; manufacturing process steps previously left out are included; and variations among companies and nations are considered.

Williams acknowledges that computers are tools that can confer many environmental benefits, such as allowing the environment to be simulated in complex models that can expand human understanding, but he also stresses that they “pack a punch, energy-wise.” They demand far more energy than any other home appliance, except a furnace or boiler, he says.

Computing equipment differs significantly from many other consumer products because the vast majority of the energy it uses over its lifetime—81%, according to Williams’ calculations—is required during the manufacturing process.

Most of the energy is used to run the plants where the computer chips are fabricated. “The overall demand of a typical chip plant is equivalent to the energy used by a U.S. city with 60,000—80,000 people,” says Ted Smith, executive director of the Silicon Valley Toxics Coalition, a nonprofit group.

The issue takes on more significance given the rapidly rising population of computers throughout the world. Worldwide, about 130 million new computers are produced every year, says H. Scott Matthews, the research director of Carnegie Mellon University’s Green Design Initiative. The world’s billionth PC was produced in 2002, Williams adds.

By the end of 2005, 600 million computers will have been sold in the United States alone, Matthews says. Of this total, 72 million will have been recycled and 150 million will be in landfills. The average computer’s lifetime is anywhere from 1 to 4.5 years, he adds.

In this context, extending the lifetime of computers becomes important. “Reselling or upgrading computers uses 5–20 times less energy than recycling,” Williams explains. Other studies have shown that many computers are shipped to the developing world, where they are recycled in environmentally destructive ways (Environ. Sci. Technol. 2002, 36, 52A–53A), such as open acid baths, he says.

Developing nations are also burdened by the ecological impacts of computer manufacturing. “We are increasingly outsourcing our material intensity requirements [to the developing world],” says Volker Türk of the Sustainable Production and Consumption department of Germany’s Wuppertal Institute. As a result, these already disadvantaged nations are taking on a larger share of the ecological impact and a smaller share of the economic value associated with electronics manufacturing, he says.

On the positive side of the equation, a growing number of progressive computer companies are also attempting to decrease the environmental impact of their computers by redesigning them.

For example, NEC began promoting what it claims to be the world’s first green PC in 2002 (Environ. Sci. Technol. 2002, 36, 370A–371A). Both NEC and Fujitsu offer computers that are designed for dismantling and do not contain lead in their circuit boards or cadmium or mercury in their batteries. Fujitsu has been taking back computers since 1988 and prides itself on its environmentally conscious product design and development, says Harald Podratzky of Fujitsu-Siemens.

But the tradeoffs are complex, stresses Steve Harper of Intel Corp., one of the world’s largest manufacturers of computer chips. Harper contends that lead used for soldering electronics products constitutes 0.5% of all the lead in the United States. And the U.S. EPA’s Design for the Environment program recently concluded that the environmental impacts of a new solder alloy that contains tin, silver, and copper would be worse than those of lead, he says.

The situation is further complicated by insufficient appreciation of how to design products for disassembly on the part of computer manufacturers, says Joseph Sarkins of Clark University in Massachusetts, which is one of the states that is actively moving toward requiring that local computer manufacturers take back their products at the end of their life spans. The EU passed a law requiring such computer “take-back” in 2003.

Many companies are nonetheless motivated to design their products to minimize environmental impact because of consumer demand, says Jerry Velasquez of the UNU Global Environment Information Centre. In Japan, studies show that 30.8% of consumers consider the environment when they purchase computers, he says.

However, Williams is dubious that market forces alone can address the complex issues associated with the environmental impacts of computing. “Unless governments regulate this [and] play an active role, it’s much more likely for the risks to dominate over opportunities,” he says. “As this issue is more complex and international than many environmental challenges we've faced, I think we need to think beyond a domestically focused command-and-control regulation model,” he adds. —KELLYN BETTS