Cover Story
Paving the Way:
Seattle Steam’s road to renewable energy
Stan Gent, President and Chief Executive Officer
Seattle Steam Co.
In 1893, downtown Seattle was getting a new start. Largely devastated by the Great Seattle Fire of 1889, the city was rebuilding: Fire-resistant structures were going up, and a
new tram system started operation. A steam engine provided DC
power for the tram and heated 17 of the city’s new buildings. It
was the beginning of district heating service; the beginning of
what is now Seattle Steam Co.
Today, the company’s district heating system is an integral
part of the community’s infrastructure, serving 200 buildings
through 18 miles of steam pipe. The privately owned system
had burned natural gas for more than 30 years. By 2005,
however, with prices rising and an increased global focus on
environmental impact, the system’s owners felt they faced
a new era that would require doing business in a carbon-constrained environment.
In 2000, the company had installed a fuel gas heat-recovery
system, which effectively made Seattle Steam’s gas-fired boiler plant
a condensing boiler plant – improving plant operating efficiencies by
nearly 7 percent and reducing associated emissions. But the owners
wanted to know what they could do next. Seattle Steam responded
by analyzing three alternatives to reduce carbon emissions:
• combined heat and power generation
• waste heat recovery from a nearby cement plant
Low local electricity rates and the relatively long distance
from Seattle Steam’s plant to the cement plant made the first two
alternatives less attractive than converting the company’s baseload
heat demand to a renewable fuel – in this case, local biomass. The
owners examined the options and agreed that using clean urban
waste wood as a renewable fuel to reduce annual carbon emissions
