The Lake Union Steam Plant that now houses ZymoGenetics turns one hundred years old this year. It’s been called the monument on Lake Union, and its story is, well, monumental. It’s one of auspicious birth – built at the start of the electric age; heroic life – providing emergency power for the city; shocking death – discovery of toxic waste; and finally resurrection – the renovation into a modern biogenetics laboratory. It begins like many great stories with a prequel – the Hydro House.
Squeezed between ZymoGenetics and an old renovated warehouse the gnome-like structure of the Hydro House on Eastlake Avenue is easy to miss and a delight to find. It was built in response to a young city’s growing energy needs and to a possible failure in the Cedar River dam.
At the turn of the 19th century, electricity was changing people’s lives in ways analogous to today’s technological revolution. As with information technology, Seattle took a leading role in electrical power. The first light bulb in Seattle, also the first west of the Rockies, “flickered to life” in just 1886, according to a HistoryLink essay. Some twenty years later, in 1905, the Cedar River Falls hydroelectric facility became “the nation’s first municipally owned hydro project,” according to Seattle City Light.
The early users of electricity, industry and commerce provided steady growth for the utility. But by the end of the first decade, a new market was opening – the home. No sooner were additional generators planned for the Cedar River station than it was apparent even more would be needed.
“The support given the municipal plant by the Seattle citizens was so enthusiastic that it became necessary to plan extensions almost as soon as service began,” a 1931 City of Seattle Department of Lighting Annual Report notes in its history section.
By 1910 city engineers decided to just tap all the energy potential of the Cedar River site by means of a large concrete dam. But there was a risk involved with the dam, a potential failure of one of the dam’s reservoir walls. To provide enough power to the city while resolving that issue, Seattle needed a back-up power source and planned for a coal-fed steam plant on the south end of Lake Union.
In 1911 voters approved financing for the initial phase of the Steam Plant. Yet it too couldn’t be built fast enough. Since actual power from the Steam Plant was still a few years away, the possibility of building a small hydro facility on the site was re-introduced. The idea for a hydro project on Lake Union had first been raised in January 1902 to power city street lights. But its funding instead went toward the much larger Cedar River Falls hydro electric project.
Now the timing was right. The Hydro House was quickly built and put into service by 1912 for a cost of about $30,000.
The Hydro House was innovative. It used the latent power of the Volunteer Park Reservoir. Overflow water propelled by gravity fell through a 40-inch pipe some 3,400 feet long with a drop of 412 feet to generate 1,500 kilowatts of power. Technically it was the city’s second electrical generating facility.
In reality, “the unit was too small to be a real factor in supplying the rapidly increasing demand but it was the first auxiliary power source for the City,” again according to the 1931 report, “and paid for itself many times over during its first three years as a standby plant in emergency.”
The Hydro House, originally called the Power House, is now a local landmark structure. In 1987 architect, preservationist and former Eastlake Community Council board member Susan Boyle nominated both it and the adjacent Steam Plant for landmark status in a well-researched, 15-page, single-spaced, typed nomination form.
The building was designed by Daniel Riggs Huntington, the City Architect from 1911-1925, who also designed many other still-standing historic structures. The Fremont Library, also a Huntington design, bears a familial resemblance to the Hydro House. Both are Mission Revival Style structures. Although, “the Lake Union Power House was a contradictory hybrid,” notes Boyle, “a new building type [electrical] clothed in an old style.”
Boyle describes the Hydro House as “a single story, wood and concrete frame structure with a basement level below the grade of Eastlake Avenue. The primary elevation is the east one on Eastlake Avenue (original drawings show no indication of Fairview Avenue, which was built later on pilings). The building is stucco-clad, clay tile, gable-roofed structure, with its ridge running parallel to the street.”
She notes that there are two small concrete towers on the structure that originally contained cross arms for transmission lines.
“The original roof towers clearly expressed the use of the building and the simple symmetrical arrangements of elements spoke of its utility, but the building’s size and style gave it a domestic character.”
A window outlook sat squarely on the roof ridge, for visually monitoring those early transmission lines. The thick north and south concrete walls of the Hydro House rise to form low roof parapets that were likely “designed to serve as fire walls to separate the Power House from neighboring buildings.”
An inset entryway was changed shortly after construction. “A pair of panel doors with a glass transom was originally set into the front opening at the east elevation to provide a small covered entry,” writes Boyle. “This was changed in 1914 when the doors were moved forward to their present location on the face of the building.”
Other changes include “the removal of grillwork and installation of windows at the two dormers and gable ends. When the building ceased to operate as a generating plant, the cross arms and exterior wires were removed. But for these changes, the exterior of the Power House today is original.”
As for the interior, only the original concrete walls and roof trusses remain.
Comparing the design of the Hydro House with the neighboring Steam Plant “clearly suggests the revolutionary character of the later building.”
The Hydro House was quickly eclipsed when the initial phase of the Steam Plant was completed in 1914. The Hydro House’s main floor, formerly a storage area (with the generators in the basement), became a lunch and locker room for Seattle City Light steam plant employees. And its loft became a darkroom for the city’s Engineering Department staff photographers.
The Hydro House continued to serve as an emergency back-up power source for some 18 years. In 1932 it was finally shut down entirely. Its generators were said to have been sold to a Christian radio station in Ecuador calling itself “The Voice of the Andes.”
“The only remnant of power generation within the Power House,” writes Boyle, “is a braced concrete pier in the basement that once supported the turbines.” Another remnant exists outside, beneath Fairview Avenue, amidst the pilings and partially submerged in Lake Union’s shallow waters, the large outflow pipe of the generators.
Today the Hydro House has a new life, owned by ZymoGenetics, and leased out as a restaurant to The Great Northwest Soup Company. In this way it still functions as it once did as a lunchroom to employees in the larger building. The restaurant is open to the public Monday through Friday, 7 a.m. to 3 p.m. While enjoying a breakfast or lunch at the Hydro House, you can look up to see those original roof trusses and also wander outside onto a modern patio for a view of Lake Union.
Next: “Life of a Steam Plant.”
A version of this article was first published in the Eastlake News, the Eastlake Community Council’s newsletter.