In an effort to create more density in South Lake Union, Seattle City Light is considering the possibility of a 40-story apartment tower developed on top of its new electrical substation on the edge of the neighborhood.
City Council members urged City Light planners to look decades ahead and imagine when parts of Seattle might be as dense as New York, which has incorporated a substation into a commercial building.
“Should we really be precluding the possibility of building over it,” Councilmember Richard Conlin said recently, “even if we don’t have the density today?”
While a tower-over-substation seems unlikely in light of new cost estimates, City Light still plans to build Seattle’s nicest and most expensive substation to accommodate its fast-growing, power-hungry neighborhoods.
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That raises questions about fairness — especially when you consider that most of the existing 11 substations amount to “a chain-link fence around a bunch of scary-looking equipment,” said Mike O’Brien, chairman of the council’s Energy and Environment Committee.
The new substation being built on Denny Way, about a block from REI, also raises questions about City Light’s policy of spreading new substation costs among all ratepayers, including those stuck with old-school substations in their neighborhoods.
The council is still a ways from deciding just what it wants the new substation — with a current “baseline” cost of $164 million — to look like.
But City Light went into planning with the understanding that “this is not going to be your grandfather’s substation,” said John Savo, an architect consulting for City Light.
“The kind of thing built in the past would be unacceptable, especially given what’s happening in the city and neighborhood,” Savo told the council recently.
Substations convert electricity coming from City Light’s hydropower dams on high-capacity lines to voltage used in households and local businesses. They also distribute that power around parts of the city.
The city hasn’t built a new substation in 30 years. No matter where a new one goes, city officials are convinced residents would no longer stand for open-air equipment behind a fence or brick wall.
City leaders are less sure how people would feel about living or working above a humming substation.
At New York’s 7 World Trade Center, for instance, a commercial skyscraper incorporates an 80-foot substation into its lower floors.
City Light looked at the possibility of the substation sharing space with a tower or two, down to the cost and number of truckloads of debris and building materials construction would require.
It’s a complicated and costly option, the utility concluded, and one it wouldn’t pursue without the council’s insistence.
Putting a tower above or near the substation would likely mean an underground substation, rejiggering expensive equipment and a dramatically reinforced structure, according to City Light.
Although the city might gain $17 million to $28 million from selling substation land to tower developers in studied scenarios, costs of the substation would increase from $22 million to $125 million.
Tower options would also delay substation completion by one to three years. And they would require at least 6,000 more truckloads of debris and material than the single-story, aboveground baseline project.
No developers have expressed interest in tower options, at least none that O’Brien knows about. That makes co-development of a substation and residential tower “very unlikely” in his mind.
Savo told the council that cities such as Beijing or Anaheim, Calif., that have buildings or parks on top of substations are dealing with smaller substations than the one Seattle is building at the old Greyhound Bus garage site on Denny Way.
The design of City Light’s most attractive baseline concept is inspired by Olympic Sculpture Park, Savo said, with a half-acre of open space and a ramped pathway around the angular substation that residents could use for exercise or dog walking.
The substation would serve more than South Lake Union, according to City Light, distributing power to downtown, the fast-growing Denny Triangle area, and eventually First Hill.
Everyone shares cost
The city’s policy, O’Brien noted, has been to treat a new substation like other systemwide improvements, such as a new generator at Ross Dam or a new transformer at your neighborhood substation. Those costs are spread among all ratepayers, he said, because “those type of enhancements benefit us all.”
An $111 million substation was figured into City Light’s budget and rate structure.
But the estimated baseline cost has increased to $164 million, Superintendent Jorge Carrasco said, because of revised estimates for construction, public amenities and power needs.
The added cost would roughly increase rates by about one-half of 1 percent unless City Light can reduce spending elsewhere by an equivalent amount.
One of the concepts considered would put the substation underground and an open space, possibly a soccer field, on top of it.
But that option, requiring more complex construction, would cost $239 million and involve 10,000 more truckloads of material than the baseline concept.
The cost of burying the substation wouldn’t justify the project, O’Brien said. It would be cheaper, he said, for the city to buy land elsewhere for a ballfield.
As for the next steps, the council expects City Light to come back within a month with staff recommendations on preferred options. The council would then suggest which ones it would like to see move to refined design and cost estimates.
Neighborhood activist John Pehrson said he prefers the one-story baseline concept with public open space. “It has many opportunities for significant public amenities,” he said.
Bob Young: 206-464-2174 or firstname.lastname@example.org