October 1, 2009
Carbon Neutral Now
Two new projects, at radically different scales, underscore the challenges facing designers who want to combat climate change aggressively.
Kroon Hall, with its blond stone walls and handsome vaulted roof, has an unassuming barnlike presence amid its neo-Gothic neighbors at Yale University. Though it fits as comfortably as an old pair of jeans, every detail of this new office and seminar-room building, from the orientation of the site to the tilt of the window louvers, has been calibrated to husband or harvest energy. Kroon leads a tiny vanguard of projects aimed at conquering green building’s next frontier: “carbon neutrality,” the reduction of net greenhouse-gas emissions to zero.
Across the continent, at the southern tip of the mountainous and densely forested Vancouver Island, Dockside Green will soon become carbon neutral. A mix of town houses, mid-rise apartments, and commercial buildings being built on a brownfield at the edge of downtown Victoria, British Columbia, the large, multiphase urban development takes a comprehensive approach to carbon reduction, showing how much is possible at the neighborhood scale.
Both projects highlight the promises and pitfalls of addressing climate change through carbon neutrality. Some rural houses and environmental-education centers already claim to be carbon neutral. They achieve most of what’s needed by employing energy-efficient measures available to any building, and then adding wind turbines or solar panels to generate electricity and even supply power to the grid. College campuses—indeed most urban buildings—can substantially cut energy use, but it is much more difficult to light every classroom and power every computer using clean, renewable sources.
At least on paper, any organization (or individual, for that matter) can eliminate its greenhouse-gas emissions by purchasing carbon credits to offset that spec office building or flight to Borneo. Ostensibly, these credits will pay to plant carbon-absorbing trees somewhere.
That makes people feel good and may even do some good, but truly walking the greenhouse-gas-reduction walk means taking advantage of every available efficiency. It’s fairly easy to reduce a building’s energy use by double digits from today’s undemanding norm without resorting to exotic technologies, and the paybacks can be short. But getting all the way to zero generally requires the generation of energy on-site or locally, through some combination of solar, wind, or other alternative-energy source. Here the up-front costs can be high and the paybacks long, given the limits of current renewable technologies.
Kroon Hall doesn’t look like a member of any vanguard. Its welcoming front plaza, backed by a louvered elevation that cuts afternoon sun, creates a pleasing meeting place, anchoring adjacent buildings occupied by research labs and the School of Forestry and Environmental Studies. Hopkins Architects, of London, working with the locally based Center-brook Architects and Planners, arranged the structure’s 218-foot length to harvest winter sun and daylight, while the wood louvers and the narrow 57-foot width cut summer heat gain. Windows are sized and arranged to draw in the sun, replacing electric lights in most daytime hours.
The quality of daylight is particularly beautiful in the top-floor reading room, with its gracefully vaulting roof. Photovoltaic panels over skylights filter celestial light, which is balanced by sidelight from the louvered walls. The room is visually warmed by wood panels that wrap ceilings and walls. Many are veneered in oak harvested using Forest Stewardship Council methods from the school’s own forests. (Yes, Yale owns forests.)
The design incorporates many strategies familiar from the best green buildings, like occupancy sensors and storm-water recycling, but the architects, with the engineers Arup and Atelier Ten, use several integrated systems to crank energy use way down. A geothermal well system draws heat from the earth in winter and cools in the summer. A displacement-ventilation system relies on the buoyancy of warm air to ventilate the building with only minimal fan use. A water spray within a special air-handling unit draws off heat as used air leaves the building. The chilled exhaust precools incoming air through a heat exchanger. Windows open for free summer ventilation, though little red and green lights signal to occupants when closing them is necessary.
“The only way to make really efficient buildings is to employ as many different strategies as possible,” Hopkins’s director, Michael Taylor, says. “In the case of Kroon Hall, these range from high levels of insulation to the 1,500-foot-deep geothermal wells. We reduced energy demand by 50 percent and then met 25 percent of the energy needs with a 100-kilowatt photovoltaic array, so we have a resulting 62.5 percent reduction in our carbon footprint.” The university will purchase carbon credits to reduce Kroon’s footprint to zero. Yale balked at the cost and land area needed to fully meet the building’s energy demand on-site.
On Vancouver Island, Dockside Green harnesses economies of scale to take advantage of strategies that are impractical for single buildings. The development sits on a narrow, 15-acre brownfield swath just above Victoria’s Inner Harbor. Residences alternate with town houses and commercial buildings ranged along a burbling stream that is planted with native wetland grasses. The master planning and the first eight buildings, by the Vancouver architects Busby Perkins + Will, seamlessly and almost invisibly incorporate green measures. Rain-harvesting gardens feed the stream, which is lined by a path and townhouse terraces. Water treated in an on-site sewer plant augments the runoff. It’s clean enough that crayfish thrive and ducks nest. Tenants plant lettuce on the roof of an apartment and scrub bathrooms using green products provided by the development’s management.
Like Kroon, the buildings are oriented for cross-ventilation and to capture warmth from the low winter sun. Awnings automatically unfurl to cut unwanted heat. These tactics, with 100 percent fresh-air mechanical ventilation, make the elimination of air-conditioning possible in Victoria’s temperate climate. Meters in each apartment provide real-time information on water use, heating bills, and electrical use and are said to mesmerize owners, who scamper about snuffing phantom kilowatts. With familiar devices, such as compact-fluorescent lighting and Energy Star appliances, Dockside Green cuts its energy use to more than 50 percent below Canada’s building-code standards.
As the project got under way, Joe Van Belleghem, a partner at Windmill West (Dockside Green’s codeveloper, with Vancity, a credit union), got plenty of local attention when he promised to write the city a $1 million check if any of the buildings fell below LEED’s Platinum-level certification. So far, he has not had to pay up. Dockside Green will eventually include 26 buildings and be home to about 2,500 people in three neighborhoods. At that scale, the developers were able to afford to build a biomass-gasification plant, which accelerates the decomposition of construction-waste wood into a clean-burning biogas that supplies hot water and hydronic heating to the entire development. Van Belleghem collects fees from residents for the heat and hot water he provides, which will largely pay for the plant’s construction. According to the architect Peter Busby, by producing its own heating fuel and supplying the excess to an adjacent hotel, Dockside Green makes up for the carbon content of the electricity it needs from the grid to power lights and appliances.
Dockside Green goes a step further by helping to reduce auto dependency. Its location links residents to four bus lines, a tiny passenger ferry—cute as a toy—that chugs to various locations around the bay, and the Galloping Goose bike path, which has become a commuting artery. The developer also subsidizes membership in a local car cooperative. “We encourage you to become a member and get in the habit of not using your own car,” Van Belleghem says. The developer will pay $25,000 to buy back the parking space built for each unit.
“To get the reduction we need in CO2 gases by 2050, we must fundamentally transform our built environment with higher densities, more walkability, and less driving,” says Christopher Leinberger, a founding partner at Arcadia Land Company and a visiting fellow at the Brookings Institute’s Metropolitan Policy Program. “Vehicle fuel efficiency alone will not be enough.” According to a new book from the Urban Land Institute, Growing Cooler: The Evidence on Urban Development and Climate Change, developments that weave together alternatives to the car can reduce transportation-related greenhouse-gas emissions by 30 percent on average.
Dockside Green’s approach is so comprehensive that it is serving as a pilot project for the U.S. Green Building Council’s LEED for Neighborhood Development program, which will certify large-scale developments. Currently, the USGBC is evaluating the proposed point system, including a controversial prerequisite to certify only developments that are, at minimum, about twice the density of typical suburbs.
While we await the miracles of “clean coal” and “risk-free” nuclear power, Dockside Green and Kroon clearly demonstrate that significant carbon reduction can occur using existing building technologies.
But the question is whether clients will be willing to pay for them. Yale analyzed every idea for Kroon but wouldn’t sign on to some innovative techniques with prohibitively long paybacks. According to Taylor, it took 2.5 percent of the building’s total budget to reduce energy consumption by 50 percent. The PV array alone, which supplies the next 25 percent of the building’s energy needs, added a similar amount to the budget, even with a cost-reducing grant. That’s a sizable chunk of cash, even for Yale. Kroon’s cost—$576 per square foot—hews to the university’s construction norms, but it’s much higher than most colleges can afford. Worse, thanks to endowment losses, Yale has put almost its entire building program on hold.
Still, Busby sees enormous carbon-cutting potential in the kind of waste-to-energy plant found at Dockside Green. “About 25 percent of Sweden’s energy comes from these kinds of loop systems,” he says. The barriers? “Cost, and the fact that everyone thinks they’re lovely but not in my backyard.” Unfortunately, most building owners still operate on first-cost math, which undervalues green strategies. Leinberger sees that changing. Some investors are only putting cash into LEED-certified buildings, he says. As this momentum builds, “LEED certification can become a prerequisite,” he adds. “And buildings that aren’t certified become the equivalent of a buggy whip—an obsolete investment.”
Some of the traditional real estate metrics are becoming obsolete anyway. “At Kroon, we found our calculations very sensitive to assumptions about fuel costs and the life span of technologies,” Taylor says.
In other words, how do you analyze paybacks when oil prices bounce around in increments of $2 per barrel and the efficiency of solar panels and wind turbines will change dramatically in five years? With Congress possibly imposing some form of carbon tax in the future, “the results are likely to be even less predictable.”
In Washington, much of the climate-change debate revolves around speculative technologies that demand enormous investment and may not even prove viable. Energy efficiency is treated almost condescendingly, as something nice to do but not particularly useful. Despite their shortcomings, Kroon and Dockside Green show a way forward. Both rely on a multitude of approaches, not a hypothetical silver bullet. And the truth is, if we can’t move forward with solar panels, wind turbines, and commonsense conservation strategies, how will we ever commit to those massive, speculative, moon-shot-scale investments? Comparatively speaking, this is the low-hanging fruit.