Denver is the home to one of the oldest heating systems in the country.
The city uses steam to warm downtown buildings, but recent changes could threaten the unique service.
From above, Denver doesn’t look old. But underneath the foundation, you’ll find history.
And some of that history leaks through — with steam.
“We have the longest, continuous running, steam, district-heating system in the nation, about 140 years,” says Jerome Davis, the regional vice president of Xcel Energy for Colorado.
Denver has a 10-mile network of pipes beneath the street.
It’s been using this type of system since 1880.
Hot water vapor is delivered to about 120 customers in downtown Denver, with the main purpose of heating buildings.
This type of system also exists in New York City and San Francisco.
“We use to have boilers sort of in several different locations,” Davis says. “We just recently consolidated the three boilers, bringing up the efficiency of them in one location. Great thing about that, again bringing up that efficiency, certainly investing in the system, which is good for our customers.”
Davis says that Xcel made some improvements to the system, and to offset that cost, the utility hiked the monthly steam heat bill by about 36 percent.
According to Davis, this was the only way to keep steam heating as an option.
Even before the latest rate increase, steam heat was losing popularity. Xcel says the total number of customers declined by 10 percent over the last decade, from 136 in 2009 to 122 this year.
Concord, Vermont got rid of its underground steam heating system of eight decades because it struggled with technical and financial issues for years, and the low price of natural gas allowed competitors to lure customers with much cheaper heating.
“Various customers who say, ‘I gotta have steam because of an economic standpoint,’ ” Davis says. “Other customers may say, ‘I gotta have it because of the way we are situated is the only type of system that would allow us to operate appropriately.’
“Choice for some customers, it might be driven by economics. For others, it might be from an environmental standpoint.”
E Cube, an energy consulting firm in Denver, says rate increases could contribute to losing customers. The firm expects the trend could force Xcel to decommission the system in the next 10 or 20 years.
But steam heating could be a secret weapon, according to the United Nations Environment Program, because it allows for easier regulation.
Steam heating delivers 50% less primary energy consumption for heating and cooling buildings, thus decreasing harmful air pollutants, which is why Davis says it’s important to keep this system working.
“I think it’s important to keep it around because some don’t have an option to change their system,” he says. “Not only do we provide this sort of pathway to a clean energy transition but we also think about the economics of how we do it.”