The UW-Madison Heating Plants: Staving Off Wisconsin Winters
By Brandon Grill
Unlike in residential neighborhoods where every house or apartment building has its own heater, a large campus like UW-Madison can afford to go big with its heating needs to keep students and faculty warm during Wisconsin’s long winters. Instead of having boilers in every building, two major heating plants supply adequate heat for the entire campus. These massive boilers are definitely unlike anything a normal home would have, each capable of generating enough heat and energy to power a sizable area of campus. This system, which has been around for over a hundred years in various forms, is continually being modernized and has recently undergone massive efficiency improvements. Jeffrey Pollei, campus utilities engineer for UW-Madison, acts as a liaison between the state and the campus when it comes to funding and resource acquisition, and also assists with project design and execution. Pollei gave the Magazine a tour of the Charter Street Heating Plant as well as some background on the history.
Before the campus expanded to the size it is today, various attempts at centralized heating were put into effect. Re-purposed buildings such as Radio Hall and the Service Annex Building were once home to heating plants. As the campus expanded, however, it became clear that larger scale plants were needed to keep up with increased capacity. The Charter Street plant was built in 1958 to allow for increased heating capacity to the campus, originally running on coal boilers. A couple decades later, when the new UW Hospital building was constructed, a second heating plant on Walnut Street opened to service it. The two main plants were connected in the late 1980’s. The third and final addition to the system was built in 2005 in a partnership with Madison Gas and Electric (MG&E), called the West Campus Cogeneration Facility.
The Charter Street plant is a large complex, a conglomerate of older buildings and newer additions. Boilers that span multiple stories spin gas and air to create optimal combustion, which is spun around and creates a spectacular plasma vortex, visible through glass openings. Also within the plant run countless pipes carrying water, pressurized steam, natural gas, fuel oil, and air. On lower levels are massive vacuums that suck air in to be pumped into the boilers. The entrance to the tunnel system is also below ground, with a massive steam pipe running across the walls and ceilings and eventually straight into the concrete wall to be transported across the campus. Although not functional during the time of the tour (and during the winter months), the Charter Street plant also has cooling capability, using refrigerants and temperature gradients to send chilled water through different pipes than steam.
The plants owned by UW and the plants owned by MG&E generate power by heating up steam through natural gas combustion, and then uses the spent steam to heat campus buildings. By using this method, less energy is wasted than if the steam was simply emitted as a waste byproduct. The boilers mainly use natural gas, but in rare cases they can be seamlessly shifted to run off of fuel oil. The massive boilers in these plants initially heat the steam up to 750°F at a pressure of 600 psi. The steam is then run through turbines to generate electricity (Up to 9.7 MW capacity). This means that around 9% of annual campus electricity use is offset by the heating plants. The steam, now at 525°F and 175 psi, is pumped into the piping in a subterranean tunnel system beneath campus and distributed to buildings across campus.
There are both benefits and drawbacks of having centralized heating, which all boil down to cost-efficiency. A high-quality home heater can achieve over 95% efficiency due to the lack of transport needed between the source and the destination. The steam distributed via the tunnel system, on the other hand, loses heat during transport from the plant to campus buildings. Up until recent efficiency improvements, the centralized heating had efficiency ratings below 85%, meaning 15% of the heat originally generated was simply dissipating before it reached its destination. Obviously, this represents a drawback in the heating plans. The true savings in a centralized heating system come from the minimal maintenance and staffing costs that more than make up for lost energy. Buildings on the UW-Madison campus no longer need to reserve space in basements for large coal boilers. Everything can be managed from a small handful of locations. In fact, the heating systems at the Charter Street plant are so stable that a night crew of just 4 people is needed to maintain the systems. If each building ran its own heating system, energy costs would go down, but the logistics of managing potentially hundreds of smaller boilers would cost astronomically more than whatever heat is lost in transport now.
Fortunately, with better technology comes better efficiency. Due to renovations across the campus system, the drawbacks to centralized heating are being diminished and the system is becoming even more efficient than previously expected. Projects such as increasing insulation thickness from 3 to 4 inches on steam piping and renovating lab buildings to use less energy have drastically improved efficiency ratings. Based on Pollei’s estimates, there has been a 10% increase in the efficiency rating from the plants, surpassing 90% overall efficiency. Even in the brutally cold winter of 2014–2015, heat generation peaked at around 875,000 pounds of steam per hour, down from a previous peak of 1.3 million pounds per hour in comparable conditions. Additionally, boilers that used to be powered completely by coal are now exclusively powered by cleaner natural gas. The first natural gas boiler was constructed in 1970, and in 2013 every coal boiler was officially replaced. Efficiency renovations are expected to continue, but funding from the state has been cut fairly significantly for projects of that nature.
One point of concern when building a centralized system is how much expansion it will be able to handle in the future. At peak production, the plants can generate up to 2.2 million pounds of steam per hour. Due to an increase in capacity with the replacement of the coal boilers, as well as the highly successful work on lowering energy use, the plants currently don’t even reach the halfway point of their capacity. This is a good thing, to some extent, because the redundancy allows for down time on individual boilers. It does, however indicate that the campus is set on its heating needs even with hypothetical expansion. Barring a shortage in natural gas, in which case reserve fuel oil could heat the campus for around 3 days, the campus is expected to have a stable source of heat for years to come. While it may seem like a ton of effort to build massive tunnels and giant boilers, it’s nice to know so much innovation and thought has gone into keeping the student body warm in the brutal Wisconsin weather.
