Architecture and Hardware

Thirsty Fabs

How the surprising water footprint of semiconductor manufacturing, datacenters, and AI solutions is sparking sustainable development.

sea storm similar to Hokusai's The Great Wave

This year, Samsung is planning to open a semiconductor chip manufacturing plant in Taylor, TX, that will cost the company an estimated $17 billion. Intel is building a $20-billion facility in Columbus, OH, and industry leaders GlobalFoundries, TSMC, and Texas Instruments are building their own so-called chip fabs in the U.S. as well. This construction boom has been spurred in part by increasing demand for the smartphones, personal electronic devices, and Artificial Intelligence (AI) services that depend on chips, and the $50 billion in funding that the 2022 CHIPS and Science Act allocated to American semiconductor manufacturing has proven to be a strong incentive. Yet the boom is global, with new plants being developed all over the world.

As companies plan these new chip fabs, one of the first questions they need to answer is where they are going to get their water.

In general, large technology firms are major consumers of water. The datacenters that power hyperscale clouds consume large amounts of electricity, and when this electricity is sourced from traditional fossil-fuel-burning power plants, the towers essential to their operation suck up local water and release it into the atmosphere through evaporative cooling. The servers inside those datacenters need to be cooled, and when the ambient air typically used to do so is too warm, some facilities will use more water to chill the air.

The technology industry’s craving for water is no secret, but researchers suspect the datacenter problem has been exacerbated by the increase in demand for AI tools, which run on cloud services. Electrical engineer Shaolei Ren at the University of California, Riverside (UC Riverside) estimates that training a foundational model like OpenAI’s GPT-3 in Microsoft’s U.S. datacenters would consume 700,000 liters (184,000 gallons) of fresh water for server cooling. This would rise to more than 2 million liters (528,000 gallons) if the model were trained in Microsoft’s less-efficient datacenters in Asia.

The use of water in semiconductor manufacturing is different. The fabrication plants that make the chips that serve as the digital brains of so many of our electronic devices and services require ultrapure water to rinse silicon wafers free of contaminants or impurities collected during the manufacturing process. “Water is almost as critical as silicon in terms of how important it is to semiconductor manufacturing,” says Fawn Bergen, Global Sustainability Director for Intel Corp.

Indeed, water supply is one of the first questions the company considers when exploring new sites for a chip fab. “We know we’re going to need so much water by a certain time,” explains Bergen, “so we work with local officials to ensure the watershed can support that and to figure out where every drop of water is going to come from.”

Scarcity & Innovation

This demand for water has sparked multiple technology leaders to commit to the goal of being water-positive by 2030, meaning they will return more water to the environment than their operations consume. In Mesa, AZ, where Google is building a new $600-million datacenter, the company announced it would use air-cooling systems to minimize water use. On a global scale, Intel purchased 10.2 billion gallons of water from utility companies in 2022 and returned 9.4 billion gallons to local watersheds and communities near its facilities through a variety of technologies and programs, including environmental remediation projects. One project modified an upstream dam in a neighboring state to increase water flow into Arizona, where the company has extensive manufacturing operations, by 277 million gallons for year.

The irony is that many semiconductor manufacturers situate fabs in areas that are water-sensitive, including Arizona and Texas. These regions are appealing in part because they are seismically inactive. Given the massive financial investment, any earthquake risk is a nonstarter, and the companies do extensive research to ensure there is a sufficient long-term supply of water before breaking ground, explains Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University. “These companies are not taking water away from existing users,” she says. “It’s not as if the water going to a plant would have gone to a critical habitat. If we were talking about a diversion of water out of a critical habitat, you’d have people coming out of the woodwork to protest. But we’re not. This is water that is available for economic use.”

Globally, operating in regions suffering from water scarcity has spurred innovation. The Taiwan Semiconductor Manufacturing Company (TSMC) has had to manage severe seasonal water shortages at its various fab facilities around the world. When TSMC began construction of a new plant, Fab 21, in the city of Tainan, Taiwan, the company simultaneously built an industrial wastewater treatment facility to feed the fab. The facility, designed to generate 67,000 tons of water daily, includes an artificial reservoir for long-term storage in the drought-prone region.

“These companies build factories that are so resource-intensive that they have to build lakes,” notes John VerWey of the Global Security, Technology, and Policy group at the Pacific Northwest National Laboratory (PNNL). “They fill up these reservoirs when the monsoons arrive in anticipation of droughts, which gives them stable warehousing of water.”

A new TSMC plant under construction in Phoenix, AZ, is actually spurring the city to build an advanced water purification plant that can treat wastewater to potable standards. With the TSMC fab, the city knows it will have a steady supply of treated wastewater to feed a purification facility, so its investment will be worthwhile. “In a way, the city adding this new water user is, through creative and smart water management, getting Phoenix to a place of greater water resilience,” observes Porter.

Consumption vs. Withdrawal

The impact of these plants should be analyzed in terms of water consumption and withdrawal, according to UC Riverside’s Ren. A power plant cooling tower that uses evaporative cooling will have a higher water consumption rate, as the water is effectively lost to the environment, transformed into vapor that could travel to a distant region. Water withdrawal, on the other hand, refers to water that is extracted from the local watershed or purchased from municipalities, but which can be recycled or returned to the area, or even to the fab itself. Generally, chip fabs withdraw water, much of which could be recycled. TSMC has a stated goal of reusing each drop of water 3.5 times within its facilities.

In Singapore, one of the more water-stressed countries in the world, the semiconductor industry accounts for 7% of Gross Domestic Product (GDP), so the government has been developing novel recycling techniques. Years ago, the country pioneered a multi-step process called NEWater that generates ultrapure water suitable for semiconductor manufacturing, and today the republic has five such plants. A new facility slated to begin operations in 2025 will be capable of turning industrial wastewater into such highly refined ultrapure NEWater suitable for chip fabs, and the Republic of Singapore’s Ministry of Sustainability announced that new wafer fabrication plants will need to recycle at least 50% of the water they use in manufacturing.

Reuse and Recycling

Experts say the technology exists to do even better. The water solutions company Gradiant has developed multiple integrated technologies to generate ultrapure water from industrial wastewater. Founded out of the Massachusetts Institute of Technology, Gradiant borrows one of nature’s tricks for its core treatment approach. The company’s Carrier Gas Extraction process, or CGE, involves heating wastewater into vapor, then collecting this purified vapor in a tower and channeling it to a dehumidifying chamber that allows the evaporated liquid to condense into purified water. In effect, the first step of the process creates clouds, while the second generates rain, disposing of salts and other impurities along the way. “It’s a simple way of treating high-contamination or high-salinity water without using high temperatures, high pressure systems, or vacuum systems,” says Anurag Bajpayee, CEO of Gradiant.

Bajpayee says this approach, when combined with a novel reverse osmosis technique and six other treatment technologies, allows for a much higher recycling rate. “In the past, a semiconductor fab would only be able to recycle 30% to 60% of its water,” explains Bajpayee, “but now we can take this all the way up to 98% or 99% recovery.”

Instead of consuming 10 million gallons a day, a fab could channel up to 9.9 million gallons back through its system, drastically reducing its daily water consumption. The source of the water will be recycled from its own process streams, resulting in a minimal water footprint. There will still be some demand for new water in a fab, since generating a single liter of ultrapure water requires approximately 1.4 liters of fresh water. Yet a plant utilizing such technologies will minimize its impact on the local water supply. Gradiant says it is getting extremely high levels of interest, especially from fabs in water-stressed areas.

The Gradiant technology, along with the varied systems and approaches under development at plants around the world, points to a more sustainable future. Ultimately, the thirst for water is a real but solvable problem, according to PNNL’s VerWey. “These are among the most savvy businesses in the world,” says VerWey. “Water is no problem compared to what they’re trying to do. Water is a challenge they can tackle and there’s ample precedence for them being able to do so.”

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