In lieu of water cooling, Google locks down renewables for Mesa data center

Google said today it has signed an eight-year contract with utility provider Salt River Project, to provide 434 megawatts of renewable energy capacity to the grid supporting Google’s first Arizona data center

• The top line: Google’s forthcoming data center in Mesa, Arizona, will be more energy intensive than others due to the fact that the tech giant opted to use air-cooling technology, in light of the region’s poor watershed health. Google estimates the data center will run on 80% carbon-free energy on an hourly basis within a year of coming online, thanks to its new agreement with Salt River Project. 
• The market grounding: Powering data centers with 100% clean energy remains a steep uphill climb for Big Tech, due in large part to the variability of sources like wind and solar, but also thanks to interconnection challenges, demand growth, and the fact that most renewable assets don’t directly power data centers themselves. The Phoenix metro area, which includes Mesa, is the second-largest data center market in the country, signing 784 MW of new capacity in 2023. The bulk of that demand comes from the cloud industry.

Google has a public goal of reaching 24/7 clean power by 2030, and has matched 100% of annual electricity consumption using renewable energy purchases since 2017. The company’s $600 million Mesa, Arizona data center is set to come online in 2025.

Mesa’s local electricity grid doesn’t have a wholesale renewable energy market, which is why the company’s deal with Salt River Project (which is a community-based, not-for-profit water and energy company serving over a million customers in the Phoenix area) isn’t structured as a traditional power purchase agreement. Instead, Google and SRP are parties to an energy supply agreement, with SRP and NextEra being parties to underlying PPAs.

The SRP agreement includes a mix of wind, solar, and battery storage from three NextEra Energy projects. Google announced today that it is the full offtaker for the 250 MW Sonoran Solar Energy Center, which began commercial operations in late 2023, and the Babbitt Ranch Project, which is set to bring 161 MW of wind power online this summer. It’s also a partial offtaker for NextEra’s Storey Solar project. 

Any energy not used by the data center — including during the months before it’s up and running — will be used for other SRP customer needs.

Google now joins Apple and Meta in opening data centers in Mesa’s relatively stable (though hot) climate, where they may soon be joined by Amazon. The presence of these mega-energy users has prompted local concern about the amount of water they use — a large data center can consume up to five million gallons of water every single day. In Mesa, Google’s new data center will be cooled with air — meaning it will likely require more electricity, but consume less of the region’s scarce water resources. (A water-cooled data center typically requires more than 250 gallons of water for every megawatt-hour of electricity the facility consumes.) 

Elsewhere, however, Google told Latitude Media that it plans to use water cooling for most data centers for the foreseeable future, including through local partnerships to use wastewater and recycled industrial water.