As school resumes this fall, nearly all dorm rooms and classrooms on the University of British Columbia’s Vancouver campus are being heated by hot water, not steam.
It may not sound like much, and the students certainly can’t tell, but for the university’s environmental footprint, the switch has been huge. Scheduled for completion by the end of this year, the conversion will save the university $5.5 million annually in operational and energy costs and cut its greenhouse gas emissions more than 22 percent.
At the same time UBC was looking at hot water, Stanford University was, too. In March, the prestigious California university cut its emissions by half and kicked out fossil fuels altogether by overhauling its energy system and switching from steam to hot water.
The University of California, Davis, is currently looking at this option to see if it could work there.
"From my perspective, it’s the wave of the future," said David Phillips, director of campus utilities at UC Davis. "I think if you take a long enough perspective on the best way to reduce your energy use, a hot water system floats to the top."
For large institutions like universities, which are bound by legacy choices on energy systems and often face budget considerations, the question they face is this: Does switching to hot water as an energy system make financial and practical sense?
For the University of British Columbia, the process began in 2007, when the university assessed its carbon footprint and realized almost 90 percent of its greenhouse gas emissions came from the natural gas-fired plant that created the steam that heated the campus’s 130 buildings. At the same time, the university was facing an $8 million bill to replace one of the five aging boilers in the plant, with the replacement of the other four boilers fast approaching.
"The question was, before we spend all this money on this existing steam systems, is there a better way?" said David Woodson, managing director for UBC’s energy and water services. "Could the economics work to switch from steam to hot water?"
To answer these questions, the university hired an energy consultant and conducted a feasibility study. From the research, both the cost of installing a hot water system and its emissions reduction capabilities seemed to make sense. Replacement and maintenance of a new plant and steam system were estimated at $190 million; hot water was an $88 million investment.
In 2011, Woodson and his team began the task of laying down about 7 miles of pipes to carry the hot water, as well as installing in existing buildings just over 100 energy transfer stations, which take hot water out of the circulatory system and move the energy it creates throughout the building. In addition, the campus is constructing a new 60-megawatt natural gas-powered hot water plant, scheduled to come online this fall.
A campuswide teaching moment
Compared with the old steam system, which heated water to 374 degrees Fahrenheit, heating hot water takes less energy and results in less energy loss. Using hot water also reduces the overall amount of water used by the process because less water is lost to evaporation.
"This steam project puts us really, really close to meeting our greenhouse gas reductions for the campus," he said. "More significantly, we now have the hot water grid in place. Our ability to find ways to heat the water is more flexible."
As a total percentage of the national economy, higher education does not represent a huge chunk of either spending or energy use, said Julian Dautremont-Smith, director of programs for the Association for the Advancement of Sustainability in Higher Education. In 2005, according to research published in the Journal of the Air & Waste Management Association, U.S. universities and other such institutions of higher education accounted for about 121 million metric tons of carbon emissions, or nearly 2 percent of the total annual U.S. carbon emissions.
However, he said, these institutions play a big role in piloting new energy efficiency and sustainability projects, such as the use of hot water to heat buildings. Increasingly, universities are expressing concerns about climate change. Many are setting emissions reduction goals to explicitly cut their carbon footprints, and a bevy of student and faculty groups are asking their boards to divest from fossil fuel companies. In addition, some universities are installing renewable energy, especially solar, on campus or are contracting with renewable energy providers to purchase clean energy.
"I don’t think we can say it’s driving the market by itself, but in conjunction with other sectors often doing the same thing, higher education plays an important role," said Dautremont-Smith. "The cool thing that separates higher education from virtually all other sectors is that all future leaders of our society — policymakers, architects, business leaders, etc. — go through an institution of higher education, so there’s a huge opportunity there to ensure those graduates understand sustainability and are equipped with the skills to solve sustainability challenges."
Many campuses went through physical expansions in the 1960s and ’70s, adding buildings, dorms and increased energy capacity as more students flocked to college. It was also a time when energy efficiency was a lower priority and energy costs were lower, said Dautremont-Smith. Most energy systems have a life span between 30 and 50 years, which means they are coming due for an upgrade.
It’s not rocket science; it’s waste heat
In 2007, Stanford took stock of its energy use as part of an initiative that would come to be known as the 2008 Energy and Climate Plan. The plan calls for the university to cut its emissions and meet long-term energy needs in a more sustainable way. It was good timing, because in just a few years, in March of this year, the contract between Stanford and the company that ran its natural gas cogeneration plant was set to expire.
The Energy and Climate Plan resulted in a proposal to build SESI, or the Stanford Energy Systems Innovations project. After it was approved by Stanford’s board of trustees in December 2011, the university began construction in September 2012.
In many ways, re-evaluating the energy use for a sprawling 8,000-acre campus with more than 1,000 buildings was akin to solving a giant puzzle, said Joseph Stagner, executive director of sustainability and energy management at Stanford.
In typical major research university fashion, Stanford poured research and development efforts into the question of whether and how a hot water system, as well as other energy system options, could work for its facilities. The university hosted sustainability working groups with faculty and students to mine for ideas. Solar, wind and a variety of other options were floated.
"While all of that was going on, we had our utility folks preparing tables on our energy use for every hour to see how much energy we’re putting out and how much we’re expending on cooling," Stagner said.
By looking at charts representing the number of hours in a year, or about 8,760, Stagner and his team could see that at Stanford, there was a 70 percent overlap in which both heating and cooling was needed on campus. A typical university building most likely contains offices and classrooms, as well as research labs and server rooms. The latter two need to be kept cooler than the offices.
Prior to installing the new system, since 1987, the university had relied on a natural gas combined heat and power, or cogeneration, plant to supply nearly all of its energy needs. The burning of natural gas was used to produce electricity and steam, which was sent to the buildings on campus. After completing its route, the steam was then returned to the plant in the form of very hot water, known as condensate.
Any waste heat from the buildings was collected by the chilled water system also circulating throughout the campus and discharged into the atmosphere through the university’s evaporative cooling towers.
Today, with SESI, it’s a different story. Waste heat collected from the buildings is still returned to the chilled water system, but now it travels to a hot water recovery loop and can be warmed back up to heat the buildings. Stagner says the new system is safer and reduces heat loss by more than 70 percent. Since waste heat is being reused, water use at the Central Energy Facility has also been cut 70 percent.
The natural gas plant is currently being decommissioned. Now, at the Central Energy Facility, electric-powered heat pumps take waste heat from the cooling system to make hot water for campus heating instead of releasing it. Starting late next year, more than half of the electricity used to create the hot water will come from solar.
At UC Davis, it’s saving water
A few years back, UC Davis created a mini loop that uses hot water to heat two dorm complexes. David Phillips, with campus facilities, said the pilot program also utilizes the recovery of waste heat from some nearby boiler stacks.
"Really, the idea is to keep expanding that," he said. For UC Davis — located in the heart of the Sacramento Valley, which is currently reeling from drought — saving water is the name of the game.
"Switching our heating system from steam to hot water has a potential to save a lot of water," he said. "But it’s an expensive proposition."
In response to the historic California drought, this spring, UC Davis began pumping recycled water through its cooling towers instead of well water to help cool the campus’s chilled water supply, which loops around the campus, cooling air handling systems before returning to the cooling plant to be rechilled.
The move saved the campus 61 million gallons of potable water annually, or about 9 percent of its total potable water use for a year. But it was a two-week project and cost a mere $20,000 in materials plus the cost of labor.
Nixing steam and going to hot water, and using recycled water at that, could have big benefits, he said.
"When you distribute steam throughout the campus, it has high energy content, and so any losses you have on the system are basically wasted energy," he said. "When you have a hot water system, temperatures are lower, losses are smaller and it’s easier to maintain."