Courtesy Xcel Energy Inc.
This log, discovered several years ago, had been hollowed out, lined with asbestos paper and wrapped
around the Denver system’s steam line in the late 1880s as a means to reduce line losses. Xcel Energy
invites its district energy colleagues to stop by when they are in Denver to see this piece of ‘insulated
main line,’ which sits in a place of honor in the company’s steam conference room.
time signed both service agreements and
purchase agreements enabling it to buy
peaking steam from various buildings in
downtown Denver.
In 1964 the company signed a long-term
agreement with the state of Colorado to
serve the nine-building State Capitol complex
with steam, which required leasing and
operating the state’s boiler plant. The State
Capitol, the main steam plant and the Zuni
Station then began to provide a ‘three-legged
stool’ approach to overall system reliability,
as each plant is located approximately 2 miles
from the other two. Dual-fuel capability at
the original plant and Zuni Station added
further reliability for customers.
In the past 10 years, the thermal business
has worked with the city of Denver to transition
some of the boilers and chillers at city facilities
downtown for use in conjunction with the
company’s district steam and chilled-water-served facilities. The additional city facilities
include the Colorado Convention Center,
Wellington E. Webb Municipal Building,
Denver City and County Building, Denver
Public Library, Denver Art Museum, The
measure consumption and price accordingly
– as compared to the former practice of
pricing the service at flat rates based on a
building’s square footage. In spite of subsequent mergers, ultimately becoming part of
the Public Service Co. of Colorado (PSCo.)
in 1923, the steam system had grown to
serve 295 customers.
Rebuilding With CHP
With the onset of the Great Depression,
a subsequent slow recovery and World War II,
the number of steam customers dwindled
to 54. Public Service Co. of Colorado commissioned a study that recommended
expanding the steam system versus closing
it down. In 1948, as a way to increase the
system’s overall reliability while reducing its
production costs, a 14-inch, 8,000-ft tie line
was constructed to connect PSCo.’s Zuni
Station electrical generating plant (built in
1900) with the steam distribution system. In
this combined heat and power application,
steam was extracted from the turbine and
sent to the steam customers. In the ensuing
years, the steam system steadily recovered
from its post-World War II lows and over
Courtesy Xcel Energy Inc.
The American House, one of the Denver steam system's original customers, was the city's leading
hotel in the 1870s through the late 1880s. Located on the northeast corner of 16th and Blake streets,
it was one of the early large brick buildings in what is today called the Lower Downtown Historic
District. According to an ordinance enacted after a devastating downtown fire in 1863, new buildings
had to be constructed of brick or stone; the ordinance was in place for about 80 years.
