UAE pioneers geothermal cooling technology to cut energy bills and emissions

The cooling demands in the Persian Gulf—especially in the UAE—are among the toughest energy challenges around. Air conditioning in the UAE isn’t just a luxury; it’s a necessity, making up as much as 70% of the country’s electricity use. To tackle this, Masdar City near Abu Dhabi has become a sort of testing ground for new technologies aimed at shrinking cooling energy needs and slashing carbon emissions. Recently, the launch of G2COOL, the first geothermal cooling plant in the region built by ADNOC and Tabreed, kicked off a major milestone. It marks a significant step toward deploying renewable energy solutions for city cooling in one of the hottest parts of the world.

Now, unlike typical geothermal projects that produce electricity, G2COOL uses underground heat directly to make chilled water for district cooling. Here’s how it works: hot water is pulled from an underground aquifer at temperatures between 80°C and 100°C. While that’s not hot enough to generate steam for turbines—nope—it’s perfect for powering lithium bromide absorption chillers, which produce cooling water at about 5°C. That chilled water then circulates through buildings in Masdar City to provide air conditioning, covering roughly 10% of the district’s cooling needs so far.

The process, called absorption cooling, is a thermodynamic cycle that uses water as the refrigerant and lithium bromide as the absorber. The geothermal heat heats the lithium bromide solution, releasing water vapor in a generator. That vapor then cools down, giving off heat to a cooling loop, and evaporates at low pressure. This evaporated vapor cools the chilled water system serving the buildings. The cycle concludes as the lithium bromide absorbs the vapor again, with excess heat dissipated through cooling towers. Although the coefficient of performance—called COP—ranges between 0.6 and 0.8, which is lower than standard electric chillers (usually 3 or more), keep in mind that in G2COOL’s case, the energy source is free geothermal heat. So, this setup results in significant electricity savings and eases demand on the grid.

An important aspect here is that G2COOL runs on a closed loop. After extracting heat, the cooled geothermal water is reinjected back into the aquifer. This step keeps the reservoir pressure and temperature stable, ensuring sustainable, long-term operation without running out of underground heat. The heat released during condensation—roughly 30-40°C—is not enough to reheat the reinjected fluid. Plus, natural geothermal gradients help the aquifer recharge over time.

The partnership between ADNOC and Tabreed aligns well with the UAE’s National Energy Strategy 2050 and ADNOC’s $15-billion push into low-carbon technologies. The project shows that geothermal energy can help decarbonize buildings’ cooling loads—a sector that usually depends heavily on natural gas-fired power stations. By cutting down on one of the largest consumers of electricity in the Gulf Cooperation Council (GCC), geothermal cooling also helps reduce carbon output in a country whose per capita emissions are actually among the highest worldwide.

Looking at data from Tabreed—which is partially owned by ENGIE—it’s clear that geothermal cooling delivers efficiency gains. Since G2COOL started operation in late 2023, using geothermal water at 90°C from two wells to power absorption chillers, it has saved roughly 3,000 MWh of electricity each year and avoided around 1,000 tons of CO₂ emissions. District cooling systems tend to be about 50% more efficient than traditional building-level air conditioning, and adding geothermal makes them even better.

Globally, using geothermal heat directly—whether for heating or cooling—has proven to be more reliable and economically viable than more complex geothermal power projects, like enhanced geothermal systems aimed mainly at electricity. For example, China has developed geothermal district heating in its northern cities, and Europe has a long history of hot water networks. Even at sites like California’s Salton Sea, geothermal expansion is cautious, mainly focusing on combined power and mineral extraction.

That said, geothermal cooling isn’t without its hurdles. Lithium bromide is corrosive, which means engineers need to select materials carefully and possibly add chemical inhibitors. Crystallization of the absorbent solution at low temperatures can cause operational issues. Well maintenance also involves dealing with reservoir chemistry and scaling problems, which add to operational complexity and costs. But, honestly, these are recognized engineering challenges, with well-understood mitigation approaches, rather than insurmountable obstacles.

Right now, G2COOL’s capacity covers only about 10% of Masdar City’s cooling needs—and that’s a tiny slice of the overall national demand—but it demonstrates that geothermal heat can be directly used for cooling even in desert environments. ADNOC’s ongoing low-carbon pilot projects suggest geothermal cooling could expand as part of a broader energy transition strategy in the UAE. As long as reservoir management and reinjection are handled properly, systems like this can provide sustainable cooling without overloading the power grid.

All in all, the ADNOC and Tabreed geothermal plant at Masdar City underscores a pragmatic, technically sound approach to applying geothermal energy in the Gulf. It’s not a magic bullet—geothermal isn’t suited everywhere—but it’s a valuable companion for specific roles, especially in hot, arid climates. Using underground heat to reduce peak electricity demands fits nicely into the bigger picture of energy transition, where geothermal serves more as a supporting player than the headline act. And frankly, its success here might just provide a model for other dry regions facing similar energy and climate hurdles to follow.

Source: Noah Wire Services