The Steam Tunnels

The MSU campus is heated by an array of tunnels located below the ground. These tunnels, often called “steam tunnels,” span for two miles and supply heat to buildings across campus.

Currently, MSU’s heating and electricity provision is in a state of transition. The heating plant, situated south of the Engineering and Physical Sciences building, used to house a coal-fired plant, from 1922-1950. Currently, the building houses three boilers which burn natural gas and produce steam to heat the campus. Steam is an inexpensive way to transfer heat because it moves simply due to a pressure change.

Within the heating plant, one boiler produces steam at a rate of 50,000 pounds per hour, and two other boilers produce steam at a rate of 100,000 pounds per hour. The boilers emit steam at 280 pounds per square inch, and the steam is fed into a turbine where the pressure is lowered to 45 pounds per square inch, which is still high — around three times as high as atmospheric pressure. The turbine also produces one megawatt of electricity, which accounts for one-seventh of the electricity used on the MSU campus while school is in session. The rest of the required electricity is obtained from the grid.

The latest development in MSU’s heating process is the addition of a geothermal source. Extending under the site of the new Jake Jabs College of Business building are 52 wells, 500 feet deep. The temperature of the earth at this depth ranges from 55 to 59 degrees Fahrenheit. Water, which either contains excess heat in the summer or is cold in the winter, runs through the wells and heat is exchanged with the earth. Thus, the heat pumps, which are located below Leon Johnson Hall, move heat from one place to another, rather than producing energy.

Geothermal is still a relatively new field of energy and MSU has the only large plant in the area. In order for geothermal to independently heat the entire campus, around 150 more wells would need to be installed. Assistant Director of Facilities Services Daniel Stevenson explained that a transition like this takes time because the cost of converting buildings is high. Despite the cost, MSU continues to pursue this source of energy in order to meet the increasing energy demands of campus while simultaneously decreasing carbon emissions.

Energy derived from both steam and from the geothermal wells is transported through pipes within the steam tunnels, which were installed in the mid-nineties. Although, the tunnels have been used for more than just steam transit, in 1997, they acted as the set for a scene in the Steven Seagal movie “The Patriot.”

Before the installation of the tunnels, pipes ran directly through the ground. These kinds of pipes still run under parts of campus. This transport process is inefficient; a lot of heat energy is lost to the ground and occasionally pipes will fail. The steam tunnels have greatly improved this process, and they allow for flexibility in adding new energy sources.