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Power Shift
September 13, 2011
Abandoned Asset Becomes Utility Flagship
By Barbara Carss
Eyesore and iconic potential were contributing factors to Nova Scotia Power’s new $53-million corporate headquarters. Utility officials saw the opportunity to rejuvenate a derelict site alongside Halifax Harbour and symbolize a shift to more environmentally benign energy sources through the transformation of a former coal-fired generating station into a modern office building.
Staff will move into the seven-storey, 129,000-square-foot facility later this summer, marking the completion of a 30-month construction project and launching a new stage in the life of one of the company’s longest held assets. Cost projections had concluded that converting the old concrete and steel structure would be less expensive than demolishing and beginning anew, developing on a different greenfield site or continuing to rent office space for the long-term, but company strategists also sought to send a message.
“One of the mantras was that we wanted an energy-efficient building because we are in the energy business,” says Paul Currie, NS Power’s Senior Project Manager for the redevelopment. “We felt we should show environmental leadership.”
The result is a building designed to achieve 55% better energy performance than the standard set in the Model National Energy Code for Buildings and LEED Platinum certification, which, if awarded, will make it the first LEED Platinum project in Atlantic Canada. To earn that status, NS Power also aimed to secure the maximum score of 10 points for energy.
“Achieving LEED Platinum is difficult, but most experts agree that getting the full 10 LEED points for energy is even more difficult,” Currie says.
Nova Scotia Power's new headquarters - Image by WZMH Architects
SOLID FAÇADE, FLEXIBLE INTERIOR SPACE
Designers had much to grapple with in converting a largely windowless industrial structure into amenable space for a white collar workforce. On the plus side, NS Power could retain the existing municipal site plan approvals by keeping the footprint of the original building, whereas a total knock-down and rebuild would have necessitated a new planning process that could have delayed the construction start by at least two years.
Even so, extensive demolition was required to accommodate the redesign. New openings were cut in the existing façade – removing about 4.5 million pounds of concrete in the process. Smokestacks were also removed from the roof and replaced with skylights, which now top a galleria that stretches the full height of the building to bring in light along a north-south axis.
Rubble from the building now provides permeable fill in a newly levelled section of the site and in the parking lot that NS Power owns across the street. While intact, however, the sturdy cladding of a structure built in phases between 1944 and 1956 presented more of a challenge for demolition crews.
“Poured concrete, over time, gets harder and harder,” explains Jay Bigelow, a Principal with WZMH Architects, the architect and lead consultant for the project. “This was a pretty arduous task because of the thickness of the concrete, which was 10 to 12 inches in most places. It certainly prolonged our whole demolition period because of the massiveness of the concrete we had to cut through.”
In contrast, turbines and other power generating equipment had been decommissioned and removed years earlier, leaving an empty cavern in the interior.
“There was very little in terms of horizontal structure, which made it easier to create the new floors, although we did have to bring in a substantial amount of steel to build the new floors within the existing shell,” Bigelow says.
The original steel columns were left exposed to preserve a sense of the building’s past. Indeed, it’s the original heavy industrial purpose that enables this architectural feature because the columns’ magnitude overrode the conventional code requirement for fire rating approval.
“It’s utilitarian engineering. It gave us some flexibility to support the new structure because the existing engineering was so massive,” Bigelow observes.
“It may have cut down a little on available floor space, but it gave us some personality,” Currie adds. “It isn’t going to look like a lot of office buildings that are essentially warehouses of floors.”
CIVIC IMPROVEMENTS
A seven-storey atrium cuts through the east-west axis of the building, creating a publicly accessible thoroughfare to see and walk from the main entrance on Lower Water Street to the boardwalk that hugs Halifax Harbour on the back side of the building. Like the north-south galleria, the atrium brings natural light into the interior space.
“It’s sort of like a cruciform effect,” Bigelow says. “Really, the idea was to connect the city to the harbour.”
The project complements other redevelopment activity in the surrounding area that is helping to change the look and economic footing of a once prosperous industrial and warehousing district that had fallen into decline.
Haligonians and tourists alike are now strolling along the boardwalk, shopping at the recently opened farmers’ market and/or visiting the museum at the nearby Pier 21 complex, or dining at the restaurants that have appeared in sync with new waterfront residential development.
The influx of 600 NS Power employees will provide a regular weekday population and more customers for local ventures. The makeover also transforms a landmark that had become something of a corporate embarrassment.
“It was highly visible and it wasn’t pretty,” Currie acknowledges. “It was an eyesore on the Halifax Harbour and it was one of the first buildings that people coming into Halifax would see.”
RESOURCES TRIGGER TECHNOLOGY CHOICES
Beyond a focal point, the harbour provides the building’s heating and cooling and was critical to securing LEED energy points. Incoming water flows through a heat exchanger and is directed to either the heating loop, which provides the building’s perimeter heating, or to the cooling loop, which delivers cooling via a network of chilled beams.
Heat pumps drive the thermodynamics that pull energy for cooling or heating from the water, including drawing heat from a colder source. The loop also allows harbour water to bypass the heat pump when it’s at the right temperature to provide free cooling. In periods where heating and cooling are used simultaneously in different parts of the building, the dual-loop configuration can move loads to the source of energy demand, reducing the need to draw water from or discharge water to the harbour.
The process is comparable to geothermal energy – albeit using water rather than the ground as a heat sink or source – but harbour water temperatures and the demand load further complicated design specifications.
"We had to find a heat pump that could work with water that is colder than 0◦ C and still draw heat out of it,” recounts Jon Douglas, Project Manager with Enermodal Engineering, the green engineering consultant for the project.
“Finding big enough heat pumps was another challenge because the largest ones usually deliver a maximum of about 30 tonnes of cooling and we needed much more. The solution was to stack 12 heat pumps together.”
Even though the system’s scale makes it somewhat unprecedented, similar heat pumps provide heating and cooling for some other buildings on the Halifax Harbour, and the engineers are eager to see the approach replicated at other applicable waterfront locations.
“It’s not a mass product concept, but all of the components that go into it are readily available. It’s not something we had to invent,” Douglas says. “It’s innovative, but it still uses proven technology. That’s what sustainability is about; it’s about designing and constructing the building to its context and using existing resources well.”
In addition to energy-saving technology and a design that maximizes natural light penetration, other green features include: interior finishes and furniture with low to no volatile organic compound (VOC) content; bicycle parking and shower facilities; water-efficient plumbing fixtures; and rainwater harvesting to irrigate the on-site plants and landscaping. The latter makes use of the cistern that once served the power plant.
“We didn’t have to excavate the hole, and we could use that to store the water from the roof,” Douglas says. “It’s another example of taking advantage of the things the site has.”
SIGNATURE SITE
Among the site’s attributes, head office workers will certainly have a reminder of the utility’s core business as they look at the power lines that stretch out from an adjacent substation. This important transmission/distribution hub, which serves Halifax’s downtown core, was the prime reason NS Power had to retain the site into the future regardless of where a new head office would be located.
Investing in the high-profile redevelopment made subsequent sense from business, corporate sustainability and community enhancement perspectives, while also allowing for some deference to a property that has had a significant place in the company’s history.
“We have owned that property since 1840. It was the first asset that Nova Scotia Power, or its predecessors, purchased when the company was formed,” Currie says. “This very quickly became the preferred option.”
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