Beddington Zero Energy Development, or BedZED, is a bold and daring urban solar village in south London, located within walking distance of the Hackbridge train station in Sutton. It was brought to fruition by a development team headed by the Peabody Trust, an affordable housing organization, and designed by Bill Dunster Architects/ZED Factory in collaboration with the BioRegional Development Group and Ove Arup and Partners.
BedZED is an 82-unit mixed-use solar village rigorously contoured to permit maximum solar access, with 109kW of PV integrated into the roofs and south-facing triple-glazed greenhouses. Multi-colored cockscomb wind cowls passively ventilating the building, as well as the striking quality of the architecture, which blends high technology with smooth curves and rich natural materials, reflect the influence of Michael Hopkins and Partners, where Bill Dunster worked for 10 years.
The design/development team took advantage of England’s regulatory framework, which mandates greenhouse gas emission reductions. In a process that Dunster describes as "using planning gain to facilitate carbon trading," the Peabody Trust negotiated with the Borough of Sutton to reduce the purchase price of this brownfield site in exchange for the project’s greenhouse gas emission credits.
Sophisticated Solar Planning
The application of solar access planning at BedZED is carried out with an almost machine-like precision not often seen in multi-family housing. Strict adherence to solar south involves some very tricky aesthetic trade-offs. Dunster describes it as a process of "achieving the right balance between human issues and the technical disciplines." To some, that would mean incorporating trees, landscapes, and buildings that bend a little to create enveloping public spaces, but bucolic flare is not one of BedZED’s strengths. However, the complex includes a plethora of interior amenities, onsite uses, and environmental benefits that more than handsomely compensate for this shortcoming.
The compact 30-unit-per-acre development incorporates over 1kW of PV per unit. The design provides full natural daylighting to all three floors of the typical south-facing housing block, delivering the passive solar gain needed to virtually eliminate all central heating needs, except for the north-facing live/work units. In keeping with other low-energy European buildings, BedZED is thermally massive to smooth out winter and summer temperature spikes, boasting 12" of super-insulation.
The full sectional profile of BedZED shows a broad roof that slopes to the north, allowing light to pass over the housing block to the next south-facing three-story block. The roof cuts down on the unit yield per block, but allows closer spacing between blocks, conserving enough land for a full-sized soccer field. The unit configuration is set up to yield up to four units per slice.
The live/work unit is situated in the back alley and has a continuous overhead skylight to make up for the loss of southern light. On the rooftops sit the rather miniscule sky gardens, which attempt to adorn the rather bleak roofscapes that are the primary view of the next housing block to the south. Although daylighting, rather than ‘a room with a view,’ is the project theme, this front/back, front/back pattern does make you think twice about the good old-fashioned Boston Back Bay streetscapes that meet face to face.
How Close to Zero Energy?
The project’s passive and active solar power produces 88,000kWh and meets 88% of the heating requirements in a climate not much different from the Pacific Northwest. The wind-assisted air-to-air heat exchange wind cowls require no pumps or fans because of their wind- and stack-effect-driven exhaust properties, and they function as the air-conditioning system in the summer.
These features are supplemented with a 130kW combined heat and power wood chip plant. Fully aware of the arguable "carbon neutral" properties of biomass energy, BedZED’s developers went a step further to ensure that the wood chips used as fuel are from tree trimming (presumably municipal), burning what would otherwise be composted.
Although questions remain about the air emissions or "carbon neutrality" of biomass chip plants, BedZED has more than made up for it with other features. Rainwater harvesting to flush the loos combined with water-efficient fixtures, such as duo-flush toilets, reduce water consumption to 50% of average usage. Heading up the green materials list are non-formaldehyde-based construction materials and bioregional sourcing of all salvaged and recycled materials within a 35-mile radius.
Dunster’s original inspiration for his ZED Factory was to take on the unsustainable daily commute, the other big piece of the energy equation. He came to the realization that the low-energy office buildings that he was designing with Hopkins did not address the wider ecological implications of the helter-skelter sprawl patterns also affecting England. The onsite office space provided by the live/work units at BedZED enable people to skip the commute. BedZED publicity materials aggressively promote the reduced car dependency of this site provided by two train lines, a tram link, and several major bus lines.
If You Build It They Will Come
We’ve come a long way from the experimental communities of 30 years ago. This generation of green innovators is challenging the conventional Madison Avenue pros by capitalizing on a growing market for premium green living accommodations that are sexy, sun-filled, and convenient.
Tom Dykoff writes, in a rave review of BedZED from The Guardian in January 2003,
"So it suits slightly lazy eco-warriors such as Marleen Stumpel, who bought a three-bedroom maisonette last year. ‘I guess I'm like most people,’ she says. ‘I want to do things for the environment, but I have a busy life. So I want it to be really convenient. I want it on a plate.’ And so it is: if you want the whole Good Life thing, it's there (there's even a green lifestyles officer on site). ‘But you don't have to get involved,’ says Stumpel. ‘Most of the green stuff you don't even notice.’"
It’s not hard to see why the BedZED model is attracting hundreds of converts on the continent, with 700 people already signed up for the next-generation zero energy development coming down the line.
What would the BedZED development team expect to find in the U.S.? A litany of neighborhood opposition and regulatory roadblocks with no climate change protocol in sight to help grease the wheels.
But good ideas travel quickly, and some developer or co-housing group pugnacious enough to connect transit to brownfield site to artist loft with energy-free living is bound to capture that untapped market and bring one of these green machines to a neighborhood near you.
Courtney Miller, AIA, heads Courtney Miller Architects and New England Solar Homes.
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