A data center pays for its power twice: once to buy it, and once to throw it away. The International Energy Agency projects that annual data center electricity consumption will roughly double from about 485TWh in 2025 to around 950TWh by 2030, with AI as the primary driver. Every joule of it has the same destination: It becomes heat. Today, almost all of that heat is thrown away.
Power = Heat
In thermodynamic terms, a data center is an electric heater that happens to perform computation on the way. The chips, memory, network, fans, and power supplies all convert electrical energy into heat in proportion to the power they draw. A facility pulling 100MW off the grid is rejecting very close to 100MW of heat into the air or water around it. The cooling system exists solely to move that heat somewhere else. The question now is whether anyone can do anything useful with it.
THE LONG SEARCH FOR A USE
For more than a decade, the industry has tried to find a use for this heat, and the results have been modest. The obstacle is quality, not quantity. The heat a data center rejects is low-grade. Air leaving the racks rarely exceeds 45° Celsius, and even liquid cooling loops typically return water within a range that is warm to the touch but cool by industrial standards. Low-grade heat is hard to use. It cannot drive most industrial processes, it loses value quickly as it travels through pipes, and the places that could use it, such as district heating networks, are rarely next door to the data center and rarely need heat in the summer. Projects that capture data center heat for nearby buildings or greenhouses do exist, and some work well, but they depend on a willing heat buyer within a short distance and a climate where that heat is wanted for much of the year. Those conditions are the exception, not the rule, which is why most rejected heat still goes straight to the atmosphere.
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ABOUT THE AUTHOR
Peter Gross, PE, brings more than 25 years of experience in engineering and design of power systems in data centers, trading floors, command and control centers, and telecommunication and broadcasting facilities. Currently, he serves as Chairman of the Board of Directors for Cato Digital, CE+T America, and Chilldyne as well as Board Member and Advisor for numerous other industry and community organizations.
Prior to his current roles, he worked at Bloom Energy as Vice President and Hewlett-Packard as Managing Partner of HP Global Technology Consulting. Previously, Gross was Founder and CEO at EYP Mission Critical Facilities, Inc. and Co-founder of the Critical Power Coalition (CPC). He likewise served as Chief Engineer at Teledyne Technologies Inc. and was a partner at PRK Associates.
He is the recipient of the 2010 Data Center Dynamics “Outstanding Contribution to the Industry” award.
Gaurav Bazaz leads the development and commercialization of technologies that regenerate power from reject heat in data centers, power generation systems, and industrial facilities. His work focuses on improving energy efficiency, reducing infrastructure requirements, and expanding available power capacity for next-generation digital infrastructure. He is the inventor on multiple patents related to energy and thermal systems and holds degrees in engineering and economics from the University of Pennsylvania’s Jerome Fisher Program in Management & Technology (M&T).
