NREL geothermal storage project to tackle data centre grid stress
‘Swift’, the supercomputer purchased by the US Department of Energy’s Advanced Manufacturing Office, is located in NREL’s HPC Data Center in the Energy Systems Integration Facility (ESIF). (Photo by Werner Slocum / NREL)
National Renewable Energy Laboratory (NREL) has launched a project to investigate whether underground thermal energy storage can ease the stress on the US power grid caused by load growth from data centres.
The project, led by NREL and funded by the US Department of Energy’s Geothermal Technologies Office, aims to address data centre cooling-system challenges.
Citing estimates from EPRI, the laborartory said energy demands are projected to consume as much as 9% of US annual electricity generation by the year 2030.
As much as 40% of data centre total annual energy consumption, it adds, is related to cooling systems, which can also use a great deal of water.
Additionally, peak demand of data centres on the hottest hours of the year are a much higher percentage and represent a large cost for the US electric grid.
This is where NREL’s project comes in.
Data centre demand
Using off-peak power to create a cold energy reserve underground, NREL says that cold underground thermal energy storage (UTES) can be incorporated into existing data centre cooling technologies and used during grid peak load hours.
This charge/discharge cycling allows the technology to be optimised based on time-of-use and other key grid parameters, similar to a conventional battery charge/discharge cycling, reducing the overall operating cost of the grid.
The key difference is that cold UTES can not only do the same diurnal storage as a conventional grid battery, but it can also achieve long-duration energy storage at seasonal time scales.
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Guangdong Zhu, a senior researcher in NREL’s Center for Energy Conversion and Storage Systems and principal investigator for the Cold UTES project, said: “The approach we’re taking is to look into the technical and economic viability of the proposed UTES technologies by projecting what data centre loads will look like over the next 30 years.
“We’ll then do some projections and grid-scale analysis to show what this technology could look like if it’s commercially deployed at a large number of data centres. We’re aiming to improve grid resilience and reduce the cost of required grid expansion.”
NREL is leading the project’s system analysis and grid impact work.
Principal investigator Zhu is joined by partners at Lawrence Berkeley National Laboratory, Princeton University and the University of Chicago to illustrate how cold UTES is commercially attractive and technically viable for large data centre cooling loads.
Andrew Chien, a professor of computer science at the University of Chicago, said: “The idea of Cold UTES is super exciting because it’s a novel player in the space of data centre energy management and cooling.
“I can’t think of another technology focused on storing cold with new opportunities to make data centres more efficient.”
Data centre cooling
Data centres typically cool computing equipment by blowing cold air over the components using a water-cooled fan coil or by directly cooling the computing equipment with cool water.
Geothermal electricity generation is one option to serve these continuous cooling and computing power requirements.
However, emerging geothermal technologies, like those that will be explored as part of NREL’s project, offer a unique opportunity, says the lab in a release, to reduce data centre cooling loads while building more resilient infrastructure that creates a stable source of cooling.
This in turn reduces the need to build power plants to serve data centre cooling loads.
Ultimately, the project hopes to reduce strain on the grid from data centres, reduce the energy cost to data centres and reduce the cost of data centre cooling systems.
The ability of Cold UTES to efficiently deliver seasonal storage could also help reduce seasonal curtailments of wind and solar generating facilities.
NREL adds that Cold UTES has the potential to reduce overall costs for the fast-growing data centre market, improve grid resiliency during extreme weather events and help reduce costs and improve reliability for all grid customers.
