Rainwater can help meet AI’s water needs

Rainwater can help meet AI’s water needs

By Justin Talbot Zorn & Bettina Warburg

End of September Microsoft announced that it had reached a deal to reopen the Three Mile Island nuclear power plant to power its growing network of data centers. Revitalizing the plant, which suffered a partial meltdown in 1979, is one of several extraordinary steps tech companies are willing to take to meet the growing energy demands of artificial intelligence, cloud computing and other technologies. Industry analysts at Transforma Insights predict the world will achieve this almost 30 billion Internet of Things devices by 2030, compared to less than 10 billion in 2020.

Yet while big tech companies tout nuclear and other low-carbon energy plans, they have presented surprisingly few ideas to meet their rapidly growing use of another scarce resource: water.

Data centers require enormous amounts of water for liquid cooling systems to absorb and dissipate the heat generated by servers. Researchers at the University of California, Riverside, have found that this can take anywhere from five to fifty ChatGPT requests consume up to 500 milliliters of water (close to the amount in a 16-ounce bottle). Those sips add up. Googling used 20 percent more water in 2022 compared to 2021, as this accelerated AI development. Microsoft’s water consumption increased by 34 percent during the same period. By 2027, the amount of water AI consumes in one year worldwide is expected to be comparable to what AI consumes a small European country consumes. Worse still, there are large numbers of data centers convenient in areas with water stress. Recently a Google data center in The Dalles, Oregon controlled a third of the city’s water supply amid drought conditions.

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While some tech companies are investing in water recycling, others are thinking long term innovations such as transporting seawater inland or even moving data centers under the ocean. Many simply ignore what their water use could ultimately cost, not to mention the specter of drought. To date, only a few technology companies have taken steps to implement perhaps the simplest, most proven, and most promising strategy for mitigating water risks: capturing rainwater from the air.

People collect rainwater since ancient times. Now there is growing interest Among water conservation advocates, the idea is to collect rain from roofs and send it to tanks through gutters. This water would then be routed through cooling systems in data centers. Recently studies show that harvesting even a small portion of the rain that falls in a given area can eliminate water shortages while replenishing groundwater and reducing pollution from stormwater runoff. There is no need for a middleman when collecting water from a roof, meaning that collecting rainwater can be cheaper than buying equivalent quantities from a municipal water supply – and avoid the greenhouse gas emissions associated with pumping water between locations.

Some states and municipalities have for years limited stormwater collection for homes and businesses due to concerns about water quality or a reduction in water supply. But more recently stands after stands has authorized the practice as evidence for conservation benefits is increasing. Cities like Tucson and Austin are now encouraging rainwater harvesting by offering incentives and setting requirements. Apple, Ford And Toyota have recently integrated rainwater harvesting systems into corporate campuses and manufacturing facilities.

But we believe that data centers offer the greatest untapped opportunity for water conservation through rainwater harvesting. It is not only that data centers have an urgent need for water, but also that their large, flat roofs are very suitable for collecting water. A roof of 50,000 square meters can do that collect approximately 31,000 liters of water from a single inch of rain – about as much as fills an average residential swimming pool. Many data centers have roofs of more than 100,000 square feet, and some hyperscale data centers owned by large technology companies have roofs of up to a million square feet.

Why don’t more data centers rely on rainwater harvesting? The costs, for example. Setting up a system for a commercial facility such as a data center typically costs between $2 and $5 per square foot, depending on the complexity of the system, storage and filtration needs. If the cost of municipal water in an area is low, it may not make sense to invest in rainwater harvesting. Additionally, rainwater systems rarely cover the total amount of water required to cool a data center. Some huge facilities can use a million gallons of water every day.

But the economics of rainwater harvesting are making more and more sense as both costs and uncertainty about water supplies increase, especially as the climate changes. Like installing solar panels, installing a rainwater harvesting system is a one-time investment that reduces energy costs in the long term. In some cases, companies can use their existing stormwater management budgets to collect rainwater. In places like the greater Dallas area, where many of the nation’s data centers are located, precipitation averages mean that rainwater harvesting systems can cover up to a third of a data center’s cooling needs, depending on its size and storage systems. Although numbers are lower in arid areas, the higher water costs in those areas tend to make the economics of rainwater harvesting more attractive. As public concern about the environmental impacts of AI and other technologies increases, companies will likely have to consider both the financial and reputational risks of inaction on water.

Some industry leaders are starting to see the potential. A Googling data center in South Carolina uses stormwater retention ponds to collect rainwater. A Microsoft data center has implemented rainwater harvesting in Sweden, reducing dependence on local water sources. Amazon Web Services highlights the potential of rainwater collection in its water-positive strategy.

At policy level green benches— the clean energy-focused financial institutions expanding across the country following a $27 billion federal investment through the Inflation Reduction Act — could soon begin providing financing for stormwater projects. Stormwater has the potential to gain bipartisan support – and possibly even tax breaks along the lines of recent renewables legislation. While the approach may be a popular cause among Democrats because of climate resilience, Republicans can support rainwater harvesting without having to accept the science of climate change or oppose fossil fuel lobbies.

At a time when Silicon Valley is focusing on energy solutions like long-dormant nuclear power plants, it may seem strange to tackle an urgent global problem using a technology as old as civilization itself. But sometimes the best solutions can come out of the blue.

This is an opinion and analysis article, and the views of the author or authors are not necessarily those of Scientific American.