Overcoming Energy Gridlock in Data Centres
In our evolving digital world, data centres are the unsung heroes, ensuring the seamless flow of information, powering cloud computing, driving AI advancements and supporting enterprise operations.
With the increased demand for data processing, the debate around efficient and sustainable energy solutions and constrained power grids is heating up. It’s time for a new approach.
Let’s shift the conversation
Enter thermal energy storage (TES), a game-changing option that could revolutionise how data centres manage energy consumption.
Thermal energy storage systems capture and store energy during off-peak periods when electricity is cheaper and use it to cool data centres during peak demand times. This method takes various forms, including chilled water tanks, ice storage systems, phase-change materials (PCMs) and ground-coupled systems.
Instead of running chillers or compressors at full capacity during the hottest, most expensive times of the day, TES allows data centres to shift cooling to low-demand periods, reducing costs, enhancing grid stability and decreasing the carbon footprint.
Why thermal energy storage matters
Data centres are energy hungry, consuming ~1-2% of global electricity, a figure expected to rise to 7-12% by 2028 due to AI, IoT and streaming services. Cooling alone accounts for 20-40% of this consumption. TES offers several advantages for data centre operators:
- Energy Cost Management: Producing cooling during off-peak hours for use during peak periods optimises efficiency and cuts energy expenses.
- Thermal Ramping Speed: TES buffers rapid data centre load changes, giving chillers time to react.
- Downsizing Cooling Plants: TES distributes the cooling load over 24 hours, potentially reducing the cooling plant size without compromising redundancy.
- Resilience and Redundancy: TES provides thermal backup during failures or interruptions, supporting uptime and service-level agreements.
- Grid Stabilisation: TES allows data centres to dynamically adjust loads in response to grid conditions, enhancing value with the rise of renewable energy sources.
- Sustainability Goals: Shifting cooling to greener, off-peak periods reduces carbon intensity, aiding companies in meeting sustainability goals like carbon neutrality or net-zero pledges.
Practical implementation varies
There are several practical methods for integrating TES into data centre infrastructure.
One method is chilled water storage, where large, insulated tanks store chilled water produced during low-demand periods. The tank gets filled with water once and then reuses that same water for decades. This approach benefits from economies of scale but requires significant space.
Another method, ice storage, freezes water overnight for daytime cooling but operates at lower temperatures than most data centres need.
Phase Change Materials (PCMs) store and release energy at selectable temperatures, closer to required load temperatures.
Lastly, Thermal Ground Storage (TGS) uses geological formations or engineered systems to store or reject heat seasonally, offering energy and cost savings but with high capital costs.
The end justifies the means
While TES offers numerous benefits, it is not without challenges. These systems require substantial upfront investment, including costs for storage tanks, specialised chillers, control systems and additional piping.
In high-density urban environments, allocating real estate for thermal storage tanks can be a significant constraint.
However, the operational savings often justify the initial investment over time, particularly in regions with variable electricity pricing. Additionally, TES can provide emergency cooling during power outages, further reducing payback periods and enhancing system value.
Concept in action
Forward-thinking data centre operators are reaping the benefits of TES. For example, a large university in California uses a campus-wide chilled water TES system to significantly reduce peak energy demand.
Trane® has over 4,000 TES installations meeting cooling loads in various commercial settings, demonstrating the versatility and effectiveness of TES.
The future of thermal management is integrated
Looking ahead, future TES applications will combine with advanced energy strategies, using intelligent software for optimisation based on real-time data.
Integrating TES with liquid cooling and on-site renewables will enhance efficiency and self-consumption.
Additionally, TES can also support grid demand response and carbon credit programmes, potentially creating new revenue streams for data centres.
Overcoming gridlock
Thermal energy storage (TES) is a strategic innovation for data centres facing rising energy costs, regulatory pressures and sustainability goals.
By decoupling cooling loads from real-time energy use, TES provides flexibility and resilience. As grid dynamics become more volatile and energy costs increase, integrating TES offers competitive advantages in cost savings, reliability, and corporate responsibility. Forward-thinking operators should view TES as a necessary future investment.
For more information on Trane capabilities, solutions and services for data centers visit: Data Center Cooling, Data Center Design | Trane Commercial HVAC.
About the author
Mark M. MacCracken, P.E., Pte., ASHRAE Fellow, LEED® Fellow
Mark MacCracken is VP of the CALMAC Portfolio of TRANE. Prior to TRANE’s purchase of CALMAC, it was one of the largest manufacturers of Thermal Energy Storage equipment in the world, with over 4,500 installations in 60 countries. In his over 48 years in the energy storage field, he has assisted in the design of hundreds of Ice Storage systems.
