How SAWS’ District Cooling System Helps CPS Energy Save

In the heated depths of San Antonio’s infamous summer, a saving grace surfaces in the form of an unassuming brown brick building. The San Antonio Water System’s (SAWS) Central Cooling Plant works seamlessly to pump millions of gallons of chilled water to the largest buildings downtown, contributing significantly to energy conservation in the city.

An Ingenious Way to Save Energy

SAWS, one of CPS Energy’s biggest electric customers, has been proactively devising ways to save energy during times when the state grid faces maximum load. As part of their energy strategy master plan introduced earlier this year, SAWS’ district cooling system acts as a potent energy conservation tool in the city.

The district cooling system ultimately aims to reduce the demand for electricity from the local grid, making it a win-win situation for both utilities. The district cooling system not only saves energy but also helps customers save money, demonstrating significant impact in conservation at a larger level.

How the District Cooling System Works

SAWS’ downtown district cooling system comprises an underground pipe network filled with recycled water, chilled at SAWS’ two district cooling plants. This chilled water then travels from the plants to around 22 buildings downtown, contributing to the cooling of these spaces. After cooling the buildings, it returns to the plants to be re-cooled thus making it a closed loop system.

This system is profoundly energy efficient as it uses and reuses the same water, utilizing SAWS’ recycled water to replace any that might be lost. Even during Texas’ booming population growth or the demand surge due to data centers, cryptocurrency mining, and artificial intelligence, this system has proven its worth in preventing the state grid from facing emergency conditions.

The Thermal Energy Storage System

SAWS district cooling system also houses a thermal energy storage system that can be utilized to instantly drop the local grid’s load by 3.5 megawatts when needed. This stored energy can power about 875 homes on a summer day. It helps in conserving more energy during peak times and uses energy at night when it’s cheaper and cleaner.

A Plan for Energy Efficiency

Beyond just the district cooling system, the broader energy strategy master plan by SAWS aims to reduce energy intensity by a notable 10% by 2028. The district cooling system currently accounts for 8% of the utility’s energy use and thus plays a significant role in this roadmap to energy conservation.

Projects on the horizon include replacing old chillers, reducing the system’s pumping speed, and procuring new control software. A cumulative $1 million investment in these three projects anticipates saving an estimated 12,750 megawatt hours per year, thus contributing proactively to the larger plan of energy reduction.

Expanding Conservation Efforts

Despite facing challenges of profitability, SAWS remains keen on growing and innovating. The utility has committed to a substantial rehab plan worth $50 million over the next five years and recently added a new customer, Kimpton Santo Hotel, to the district cooling system.

The district cooling get-up highlights the potential of efficient use of existing resources to contribute to broader energy conservation. It also sets a strong precedent for other businesses to draw from, thereby finding a way to strengthen sustainability efforts while improving their bottom line.