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Partnering with other companies, Amazon will use waste heat from a data center in a Seattle skyscraper to warm its soaring new Denny Triangle campus across the street.

The project, believed to be the first of its kind in the country, will send water coursing back and forth through pipes under Sixth Avenue and could pave the way for a large swath of Seattle to recycle energy, City Councilmember Mike O’Brien said.

“I think it’s outstanding,” O’Brien said. “It’s one of the most exciting things I’ve seen in a while. I see it as having huge potential for our community.”

The system involving Amazon, Clise Properties and building-design firm McKinstry will help Amazon and Clise use less electricity and water and save money, they say.

The project is worth supporting because it will be a model for energy efficiency, O’Brien said. The council voted in September to grant conceptual approval for the pipes.

“We have a commitment as a city to become carbon-neutral by 2050,” O’Brien said. “Some structural changes need to happen, and one of them is having district energy systems that allow us to manage energy use and reduce waste.”

The system will use heat generated by computers and servers inside the Westin Building, a 34-floor office tower at Virginia Street and Sixth Avenue.

The building, owned by Clise, houses a vast data center and a high-tech Internet exchange point where communication networks connect with each other.

The three-block campus that Amazon is constructing between Westlake Avenue, Blanchard Street and Sixth Avenue will include three high-rise towers and three smaller buildings, including one made out of glass and steel spheres.

The first tower is rising and is scheduled for completion next year.

The Westin Building now gets rid of its waste heat by sending water from the data center to cooling towers on the roof of the building.

During cold weather, the new system designed by McKinstry will send the Westin Building’s hot water under the street to the Amazon campus. Equipment there will extract heat from the water and use it to warm the campus. The water then will be returned to the Westin Building to cool the data center again.

The timeline for the project isn’t set because it needs final city approval to build, maintain and operate the underground pipes.

“The nuts and bolts are relatively straightforward,” said Ash Awad, McKinstry’s vice president for energy and facility services. “You have this data center that puts off a lot of heat. The question really comes down to what you do with the heat.”

The finished system will save Amazon about 80 million kilowatt hours of electricity over 25 years, Awad says, which could equal hundreds of thousands of dollars a year. The average Seattle home uses about 10,000 kilowatt hours each year.

“We’ll have the world’s largest Internet retailer heating its office space with waste heat created by the Internet,” said Richard Stevenson, president of Clise.

The project won’t stop Seattle City Light from building new infrastructure to accommodate other growth in Denny Triangle and South Lake Union, officials say.

That means the project won’t provide much relief for ordinary electricity customers, who are helping to pay for the infrastructure improvements through rate increases.

Mayor Ed Murray’s Capital Improvement Program for 2015 to 2020 includes hundreds of millions of dollars for City Light work on and around Denny Way.

Still, proponents of the district energy system insist it will have broad benefits.

“By not using as much power during the winter months, we’ll save energy for other people to use,” Stevenson said.

Amazon is building its new campus in a particular way so it can use hydronic heating, he said.

The shared system will be “nearly four times more efficient than a traditional heating system,” said Amazon spokesman Ty Rogers.

City Light is enthusiastic about the project and will likely offer the partners a financial incentive, said Scott Thomsen, a spokesman for the utility.

There are other systems around the country, including several on university campuses, which share heat generated in a centralized location throughout a district. But Stevenson and Awad think the Denny Triangle system will be the first to transfer energy in a closed loop between properties owned by different firms.

While Seattle officials have been interested in district energy for years, their involvement with the Denny Triangle system will be limited to permitting the project.

But as the city revamps the grid in Denny Triangle and South Lake Union, officials may be able to lay the groundwork for an expanded system, O’Brien said.

“The hope is that we could get more buildings to come on,” he said, noting that the city could offer more incentives to businesses and property owners.

Information from The Seattle Times archives is included in this report. Daniel Beekman: 206-464-2164 or dbeekman@seattletimes.com