The University of Minnesota campus quite literally runs on steam -- lots and lots of steam. It's used for heating in the winter, and powers equipment that provides air conditioning in the summer.
For decades that steam has been created at a university power plant fired by coal and natural gas. But after years of concern over pollution, university officials say they're going to drastically reduce the amount of coal burned at the facility near downtown Minneapolis, about 100 yards from the Mississippi River.
The plant's three drab gray chimneys tower dozens of stories over a small riverside park and the iconic Stone Arch Bridge.
Originally built in the early 1900s, the plant provided street cars with power. In 1976, long after street cars disappeared, the university bought the plant from Xcel Energy, then called Northern States Power Co., to make steam for its Minneapolis campus.
Mike Nagel, the university's assistant director of energy management, monitors its temperature from the plant's control room.
"It's leaving here at 391 degrees Fahrenheit," Nagel said. "So you can see there's about 112,000 pounds of steam per hour going out the door."
To boil water into steam, the plant burns natural gas and about 40,000 tons of coal each year. And the steam-making process is about to change.
Under a new plan, cleaner-burning natural gas and biomass -- from oat hulls, a waste product from the General Mills cereal plant -- will provide the campus with steam. Coal would only be used as a backup on the coldest days of winter.
On those days, Xcel Energy would reduce the amount of natural gas available to the university so the power company's residential customers get the gas they need. The university would fire up their coal burners to keep a reliable flow of steam going to campus.
But that would still reduce the amount of coal used by 85 percent a year, Nagel said.
It's all part of a bigger plan by the university to reduce its carbon footprint. University officials have pledged that the Twin Cities campus will be carbon neutral in less than 40 years. They also hope to cut carbon dioxide emissions in half within 10 years.
Reducing the use of coal is just one part of the plan. University officials have re-engineered several buildings on campus to be more energy efficient. They're also reminding employees to turn out the lights and turn off their computers when they're not in use.
"We're a research university; we're trying to always find new ways to do things and the best way to do it," said Mike Berthelsen, who is in charge of facilities management at the university's Twin Cities campus. "In this case, we think we found a more sustainable way that we can still meet the reliability needs, but use significantly less coal."
One university student group, called Campus Beyond Coal, has been pushing hard to get the school to stop burning coal altogether. The group didn't get its wish entirely, since the university still plans to burn some 10,000 tons of coal annually.
But student Phil Kelly still sees their effort as a success.
"We've always been excited to hear any proposal to even reduce any coal amount," he said.
The University of Minnesota is not alone in its plan to reduce the amount of coal being burned. Over the past year more than a dozen colleges nationwide promised to find new ways to create the steam, heat and power they need to operate.
At Miami University in Oxford, Ohio, college officials say they'll stop burning coal at a plant on the edge of campus by 2025.
"This was a very challenging decision," said David Prytherch, the school's sustainability coordinator. "We're really just at the beginning of it now -- of the planning for this future without coal."
Just how the western Ohio campus will end its reliance on coal isn't exactly clear. But Prytherch thinks the school will do it by burning natural gas and conserving energy on campus.
"We've begun with a realization that there are more sustainable ways of heating the campus," he said. "But the question of how do we get there requires time."
University of Minnesota officials have yet to promise they'll stop burning coal entirely at their steam plant.
They say that may change in the future as they experiment with renewable sources of energy, like solar and geothermal, to provide the campus with the steam power it needs.