Buried deep beneath the Jordan Quad Parking Lot is a tank so massive that it can hold 4 million gallons of water. Every night, tubes inside the tank are filled with below-zero temperature ammonia, turning the water in the tank into a giant, 8-million-pound cube of ice.

“It’s not really a big ice cube,” it’s a series of 1-inch-diameter tubes, said Robert Reid, the manager of Stanford’s Energy Service.

But how are they shaped?

“They’re in rectangular blocks that are 20 feet by 10 feet, and we have 40 of them.”

And how are they arranged?

Side by side, Reid said. And then he admitted it.

“So from far away it could resemble a giant cube of ice.”

This non-ice-cube contains 360 miles of the steel tubing Reid described. When these tubes are filled with antifreeze, the water surrounding the tubes turn into 3.5-inch diameter cylinders of ice.

Stanford is in the ice-making business for one reason only: to save $500,000 every year on energy costs. In the summer, ice is created at night when energy demands are low. During the day, the stored energy is then used to cool campus, by hooking up to the chilled water system that runs out to approximately 120 buildings on campus.

The Ice Plant — an unmarked building on the corner of Campus and Jordan Way — is the largest facility of its type west of the Mississippi, and one of four plants that comprise Stanford’s Central Energy Facilities. Within the walls is a crew of approximately 30 people who constantly monitor and maintain the facilities responsible for powering the entire University.

Why ice?

The technology behind the non-ice-cube and similar forms of energy storage is not new. The tank itself was built in 1976 to chill cold water. But as the demand for energy increased, Stanford decided to spend $22 million in 1996 to convert the facility to an ice cooler. There was not enough space to increase the size of the tank, and ice can store almost three times as much energy as water in the same amount of space.

Since the new plant opened in 1999, there have been several changes, none major. The system is mechanically complex, so most of the modifications have been programming-related, with plant managers constantly fine-tuning for optimal performance.

Similarly, no major future changes are slated for the non-ice-cube.

“There’s a project to improve its capability to deliver chilled water,” said Reid. This would, he added, help the plant meet energy demand for future buildings.

Visits to the Ice Plant are free and tours are given frequently to energy clubs or by special request.