A team of Rice University researchers has found a way to convert data center waste into clean power using rooftop solar collectors. Photo courtesy Rice University.

As data centers expand, their energy demands rise as well. Researchers at Rice University have discovered a way to capture low-temperature waste heat from data centers and convert it back into usable power.

The team has introduced a novel solar thermal-boosted organic Rankine cycle (ORC)—a power system that uses a safe working fluid to make electricity from heat. The design incorporates low-cost rooftop flat-plate solar collectors, which warm the data center’s coolant stream before it enters the ORC. The findings, published in Solar Energy, show that the additional “solar bump” helps surpass the technical roadblocks with data center waste, which has typically been too cool to generate power on its own.

The research was supported by the Alliance for Sustainable Energy LLC, the National Renewable Energy Laboratory and the U.S. Department of Energy.

“There’s an invisible river of warm air flowing out of data centers,” Laura Schaefer, the Burton J. and Ann M. McMurtry Chair of Mechanical Engineering at Rice and co-author of the paper, said in a news release. “Our question was: Can we nudge that heat to a slightly higher temperature with sunlight and convert a lot more of it into electricity? The answer is yes, and it’s economically compelling.”

Traditionally, electric heat pumps have been used to raise temperatures before recovery, but the benefits were limited because the pumps consumed significant extra power.

Kashif Liaqat, a graduate student in mechanical engineering at Rice, and Schaefer achieved a "temperature lift” by using solar energy to create thermoeconomic models. They modeled affordable, low-profile rooftop solar collectors that fed into an ORC and tied into a liquid-cooling loop. The collectors were validated against industry tools and tested at some of America’s largest data center hubs in Ashburn, Virginia, and Los Angeles, which provided varying climate challenges.

The system recovered 60 percent to 80 percent more electricity annually from the same waste heat, with a 60 percent boost in Ashburn and an 80 percent boost in Los Angeles, according to Rice. It also achieved over 8 percent higher ORC efficiency during peak hours, and an increase in annual average efficiency. The approach also lowered the cost of electricity from the recovered power by 5.5 percent in Ashburn and by 16.5 percent in Los Angeles.

“What the industry considers a weakness becomes a strength once you add solar,” Liaqat said in a news release. “That’s great news for modern data centers.”

Next up, the team will look to pilot its hybrid system in operational sites and explore thermal storage, which the researchers hope could bank solar heat during the day to assist with energy recovery efforts at night.

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TotalEnergies expands solar joint venture with $1.2B portfolio in Texas, Ohio

solar expansion

TotalEnergies, a French company whose U.S. headquarters is in Houston, announced this month that it is expanding its renewable energy joint venture with New York-based investment firm KKR by adding 700 megawatts of utility-scale solar projects.

The deal will add three utility-scale solar assets in Texas and Ohio, which are expected to reach commercial operation by Q1 2027, according to a news release from the company. The portfolio is valued at $1.2 billion.

The 50/50 joint venture between TotalEnergies and KKR currently holds 1.4 gigawatts of renewable energy and will grow to 2.1 gigawatts.

The new deal is expected to close this year. Once completed, TotalEnergies will operate the assets. The electricity generated from the solar projects will be sold to third parties, the company reports.

The companies originally formed the joint venture about a year ago when TotalEnergies sold KKR a 50 percent stake in a North American solar portfolio valued at $1.25 billion. The deal originally included six utility-scale solar assets, primarily located in the U.S.

“TotalEnergies is a renewable energy industry leader globally, and we are thrilled to establish this joint venture with the TotalEnergies team to support their renewables business," Cecilio Velasco, managing director KKR, said in a release last year. “We have long been investors in renewables through our infrastructure platform, having committed more than $23 billion to date in energy transition investments. TotalEnergies’ North American solar portfolio is a great fit for us, representing high-quality renewable energy assets with long term contracts.”

TotalEnergies reports that by June 2026 it held more than 37 gigawatts of gross renewable power generation capacity. It aims to achieve over 100 terawatt-hours of net electricity production by 2030.

The company signed a major power purchase agreement with Google earlier this year. Through the deal, TotalEnergies will supply the tech giant with 1 gigawatt of solar power for its data centers in Texas over a 15-year span.

However, the company also recently redirected nearly $1 billion in capital away from wind energy projects and "decided to renounce offshore wind development in the United States." Read more here.

Houston researchers develop compact carbon capture tech for data centers

AI emissions

Two scientists from the University of Houston have been experimenting with new carbon capture systems that fit inside a standard shipping container, which have the potential to make eliminating carbon output from industrial sites much easier.

The capture of industrial carbon is an important complement to the fight against climate change, as well as winning tax credits for businesses that use carbon capture technology.

The problem is that such systems are often measured in acres, making them expensive to build and extremely power-hungry to actually use. UH Engineering Professor Mim Rahimi and former UH Ph.D. student Ahmad Hassan (now a postdoctoral associate at Harvard) have managed to fit their new system, the Small Modular Electrochemical Container (SMECs), inside a standard 40-foot shipping crate, making them compact and modular enough to be installed almost anywhere for operations of all sizes. Their research was recently published in the journal Environmental Science & Technology.

“With a conventional system, you’re building a 130-foot-tall structure designed for a specific power plant. With our technology, we can adjust the capacity by simply turning containers on or off,” Rahimi said in a news release. “That flexibility is particularly important for data centers, where electricity can come from a combination of natural gas and renewable sources.”

Rahimi and Hassan used simulated gas models to show that under optimal conditions, the SMEC used electrochemically mediated amine regeneration (EMAR) cells developed in Rahimi’s lab to capture 90 percent of carbon under optimal conditions through 300 cycles over 50 hours.

Encouraged, the team then modeled a 360-megawatt natural gas power plant associated with OpenAI’s Stargate AI data center project in Abilene, Texas. In addition to the savings on infrastructure costs, 20 of the researchers’ shipping container systems were able to capture 98 percent of carbon from Stargate’s 875-acre campus based on the model.

The looming energy costs and subsequent carbon emissions from data centers are a real concern. Estimates from the U.S. Department of Energy hypothesize that 12 percent of America’s energy needs could be gobbled up by the centers as soon as 2028. That is a massive new source of carbon. The flexibility of the SMEC means they can be deployed wherever the centers spring up.

“We’re taking a technology that traditionally requires enormous infrastructure and finding a way to fit it inside a shipping container,” Rahimi added in the release. “That opens up entirely new possibilities for how and where carbon capture systems can be used.”

In the future, the researchers say they plan to look at ways to adapt the technology to capture carbon dioxide directly from the atmosphere.