The global financial crisis has derailed construction all over the world — even in the oil-rich United Arab Emirates. But certain megaprojects continue to march ahead, though with tighter budgets, more pragmatic goals, and less ambitious schedules. One such project is Masdar City, in Abu Dhabi. In 2007, the government-owned Abu Dhabi Future Energy Company chose a consortium led by London-based Foster + Partners to design the master plan for the 2.3-square-mile development it touted as the world’s first zero-carbon city. Originally slated for completion by 2016, plans for Masdar included housing, cultural institutions, educational and research facilities, and space for tenants focused on the development of advanced energy technologies. The developers envisioned that the city, located about 20 miles from central Abu Dhabi, would eventually have a daytime population of 90,000 people.
- ETFE Panels: Vector Foiltec
- Zinc roof cladding: Mero
- Air monitoring system: Aircuity
- Roof-mounted PVs and thermal collectors: SunEdison
However, Masdar officials have reevaluated their plans. The original $22 billion budget has been reduced by 15 percent and completion pushed back to 2025. Alan Frost, director of Masdar City, maintains that the drawn-out schedule has a silver lining. “The slowing [of construction] means we can improve the project as we go along,” he says.
Among the changes is a revised power-generation strategy. Initially, Masdar was to have its own grid and depend only on renewable power generated on-site. But the development is now grid-connected. And though it includes its own 10 MW photovoltaic (PV) field that generates considerably more electricity than is consumed by current operations, the city will likely require power from additional renewable sources located outside the project boundary as the population grows.
Despite such adjustments, the development’s core principles have not been sacrificed, insist members of the project team. “Masdar is still a compact, high-density, mixed-use development, with well-integrated public transport and a street design that enforces walkable communities and neighborhoods,” says Jurgen Happ, a Foster associate partner.
The planning principles that Happ cites are evident in the first piece of the development — 680,000 square feet of a 3.7 million-square-foot campus designed by Foster for the Masdar Institute of Science and Technology. Occupied since November, the completed portion of this graduate-level university dedicated to the study of sustainability comprises a laboratory, a library, and student housing. The mostly concrete framed buildings, all under four stories, are elevated 25 feet above the desert floor on a podium and define narrow pedestrian streets and intimately scaled courtyards. Vehicular traffic, segregated to the zone within the podium’s undercroft, is limited to an electric-powered fleet of 13 driverless “personal rapid transit” cars, or PRTs. Visitors and commuters park their own cars at the edge of the development before boarding one of the podlike, remotely controlled PRTs. Other transportation options are planned for the parts of the city beyond the institute’s campus, including electric buses and other low-emissions vehicles. Eventually, a light-rail system and a metro line will connect Masdar to Abu Dhabi and surrounding developments.
For the structures that make up the completed section of the institute, as well as an adjacent 925,000 square feet of housing, lab space, and recreational facilities currently under construction, Masdar will not be seeking certification under any of the green building assessment tools, such as the U.S. Green Building Council’s LEED or the U.K.-based BREEAM. Future phases will seek a rating from the emirate’s own Pearl Rating System (see related sidebar), required since late last year for all building projects that apply for a permit from the Abu Dhabi Urban Planning Council. But despite the lack of the imprimatur of certification, the goals for these first phases of the development can still be considered aggressive: The buildings are designed to use less than half of the energy of those that comply with the U.S. energy standard, ASHRAE 90.1-2004.
The scheme includes more than a few high-tech devices and materials. The research laboratories, for example, have an exterior envelope made of ethylene tetrafluoroethylene (ETFE) — a plastic with a high insulation value that is a cousin of Teflon. Inside the labs, a sophisticated network of sensors track carbon dioxide and particulate levels, humidity, and temperature, among other characteristics. The system helps maintain good indoor air quality while keeping air change rates to a minimum, reducing the considerable energy associated with ventilation in a typical lab. And in addition to the utility-scale power plant on the outskirts of the development, the roofs of the completed buildings are covered with PV panels providing 1,800 MWh of electricity each year and evacuated thermal collectors that satisfy about 75 percent of hot water demand.
But despite such bells and whistles, the completed institute buildings are most remarkable for their reliance on low-tech, passive strategies. The design team’s first priority was to reduce energy loads by carefully configuring streets and other urban spaces and optimizing building form and orientation. “The question we constantly asked ourselves was, ‘Can we avoid an active system?’” says Edward Garrod, previously a director at PHA, the project’s environmental design consultant. Earlier this year, the London-based firm was acquired by Foster, where Garrod is now a partner.
The institute’s buildings are the product of in-depth environmental analyses, including solar studies, wind tunnel testing, and energy simulation. Even the library, enclosed by a zinc-clad, glue-laminated structure shaped like a helmet, is the result of such investigation, rather than architectural caprice, say the designers. The form is the outcome of a desire to maximize energy collection from roof-mounted PVs while shielding the interior from direct sun but giving students a view of a linear park.
Except for undulant balconies, the other structures are rectilinear and set as close as 10 feet apart. Their ground floors step back under colonnades at the edge of short streets that turn and change direction. The configuration, common in traditional Arab settlements, helps accelerate the movement of air, explains Gerard Evenden, a Foster senior partner.
Other features also take cues from vernacular features, such as the glass-reinforced concrete latticework — a contemporary take on a mashrabiya screen — that shades the curvy balconies. Another reinterpretation of the region’s traditional architectural devices is the 150-foot-tall, steel-framed wind tower in one of the courtyards. Foster’s version has operable louvers that adjust to guide air downward, while mist is sprayed from the top of the structure. The combination of evaporative cooling and moving air helps moderate perceived temperatures at the tower’s base.
Within the buildings, designers have treated circulation areas as “climate lobbies” — transitional zones maintained at a warmer temperature than the regularly occupied interior spaces. The residential structures, for example, have central atria largely illuminated by daylight through skylights configured to prevent the penetration of direct sunlight and associated heat. For much of the year, the spaces are cooled by natural means with night air drawn into the lower floors through grilles, and vented, via the stack effect, through roof-level openings. The thermal mass of the surrounding walls helps modulate the temperature over the course of the day, keeping the space at around 86 degrees. This higher set point conserves energy and, somewhat counterintuitively, also increases occupant comfort: It helps prevent the “thermal shock” experienced when one walks into a very cool space from intense heat, explains Garrod.
In addition to energy and comfort, water is also a key issue at Masdar, as it is for the region. Strategies deployed at the completed part of the project should reduce consumption by 54 percent when compared to UAE standard practice. The buildings include low-flow fixtures, efficient appliances, and a graywater treatment system that receives condensate from cooling towers. The recycled water is used to flush toilets and for irrigation.
Masdar’s sustainability objectives also influenced material choices. One example is the ground granulated blast-furnace slag that replaces a significant portion of the Portland cement in the structure’s concrete mix — up to 80 percent in some places. The use of the slag, which is a byproduct of steel-making, reduced the carbon footprint associated with the structure. It also improved constructability by slowing the concrete’s hydration and reducing the heat generated in the process, explains Albert Taylor, director of the project’s structural engineer, London-based Adams Kara Taylor.
In the coming months, Masdar officials expect to award the construction contract for the city’s headquarters building, designed by Chicago architecture firm Adrian Smith + Gordon Gill. And by 2015, they estimate that about 10 million square feet, or a quarter of the city, will be completed. But the pragmatic Frost is in no hurry to prove a point. “The timeframe from design and construction to completion,” he says, “must result in a project on the leading edge, not one on the bleeding edge.”
Dubai-based journalist Sona Nambiar is a former architecture editor with Emirates Business 24/7, The Big Project, and Architecture+.
Masdar, the development designed by London-based Foster + Partners for a 2.3-square-mile plot of land not far from Abu Dhabi’s airport, has ambitions to become one of the world’s greenest cities. However, for the first completed 680,000-square-foot piece of the development, and another 925,000 square feet under construction, officials decided not to pursue certification under any green building rating systems. “The clients were keen for us to take a holistic approach using the best of LEED and BREEAM,” says Foster partner Edward Garrod, referring to two of the most established assessment tools.
Future phases of the megaproject, slated for completion in stages by 2025, will comply with Abu Dhabi’s own Pearl Rating System, launched last year and now required for any project that applies for a planning or construction permit from the emirate’s Urban Planning Council (UPC). The new system is a key component of the UPC’s Estidama initiative, a program intended to guide responsible development that takes its name from the Arabic word for sustainability.
Like the U.S. Green Building Council’s LEED, the Pearl Rating System is point-based, but instead of earning a Certified, Silver, Gold, or Platinum certification, projects earn “Pearls.” The minimum, one Pearl, is required for all privately funded projects, while those that depend on government funds must earn at least two Pearls. The highest possible rating, five Pearls, requires a level of performance that approaches that of the so-called “beyond platinum” Living Building program established by the Cascadia Green Building Council. A five-Pearl building is one with limited reliance on grid energy and utility-supplied water, explains John Madden, senior planning manager on the Estidama team.
According to its creators, the Pearl standard is tailored to the emirate’s climate and the culture. One example is the emphasis on water conservation, with almost 25 percent of available points geared toward the regionally important issue. The system, which encompasses communities, individual commercial and institutional buildings, and residential construction, also encourages well-planned and walkable neighborhoods that make use of vernacular forms and passive design strategies.
Certification requires an integrated design process, intended to ensure the early involvement of professionals from diverse disciplines. Project teams demonstrate their compliance by including documentation such as meeting-attendee lists as part of their project submittals. The requirement’s goal is to help teams establish targets for land use, density, and performance, and realize potential synergies.
From the first stages of the assessment tool’s development, the Masdar team has been providing feedback to the UPC. It continues to share information, especially in the area of sustainable building materials. “The intent,” according to Madden, ”is to use the information to help evolve the Pearl system and to ultimately transform the market.”— Joann Gonchar