Case Study extracted from Salat, Serge. 2021. Integrated Guidelines for Sustainable Neighbourhood Design. Urban Morphology and Complex Systems Institute 2021. © UMCSII.

Photo credits: by ©Françoise Labbé

BedZED, or Beddington Zero (fossil) Energy Development, is the UK’s largest eco-village. The development was designed by architect Bill Dunster. BedZED integrates systems and creates a green and circular neighbourhood. The project demonstrates how green living is an appealing and affordable option. By combining zero net and a high quality of life, BedZed is a pioneer of the pathway to net zero proposed by the course. It embodies the circular economy and sustainable living principles proposed by UNEP. The development celebrates adaptable spaces that can be used by all residents and offers gardens to most dwellings. Integration of passive design, energy efficiency, district energy, renewable energy, and water conservation besides a car club and local organic food deliveries has been highly successful in reducing the environmental footprint. 

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Over half of the resources consumed across the world are used in the construction and running of buildings. Five percent of energy generated globally is used to construct buildings and 45% is used to heat, light and ventilate them[1]. Addressing the environmental sustainability of buildings is fundamental to meeting eco-footprint reduction targets. 

Key partners and actors

The idea for BedZED was conceived in 1997. Bioregional, architect Bill Dunster and engineers Arup were looking for an opportunity to create a zero-carbon eco-village. Alongside developer Peabody Trust, the project partners managed to secure the land and construction began in 2001.

BioRegional is an entrepreneurial charity, which invents and delivers practical solutions for sustainability. Bioregional acted as sustainability advisors to the design team, steering green transport planning, renewable energy solutions, the selection and sourcing of construction materials and a ‘green lifestyles’ programme to residents and businesses in transport, local food and composting initiatives.

BedZED is owned and managed by Peabody. Founded in 1862, Peabody is one of London’s best known and largest housing associations. Peabody owns or manages over 19,000 properties housing some 50,000 people. As well as providing affordable housing, it offers a range of learning, volunteering, personal development and community activities. 

A Community with Sustainable Lifestyles

The design was not limited to empower green techniques, but it envisioned a more comprehensive strategic thinking, encompassing the environmental, social and economic dimension of sustainability. 

Features of the site have been retained or enhanced to increase biodiversity and natural amenity value. The boundary line of mature horse chestnut trees has been retained. The ditches have been developed into water features. Private gardens are provided to 71 of the 82 units. These are an average size of 16m2 and are predominantly roof gardens on top of workspaces. The development offers mixed tenure, two-thirds affordable or social housing, lower fuel and water costs, community space, sports pitch, child-care facilities, ‘village square’, and private gardens for most units.

Besides having residential, lifework and commercial units, BedZED provides community facilities. Units accommodate a child-care facility and a doctor’s surgery. A sports pitch and a clubhouse provide communal space. A multipurpose space currently houses the BedZED exhibition. Community events regularly use it. A village square with native trees and seating lies at the heart of the development. It forms part of the pedestrian route through the site.

BedZed is a pioneer in sustainable transportation. It achieves a 50% reduction in transport energy consumption through a combination of public transport, car clubs, walking and cycling.

One method of reducing car ownership and use is the car club, ZEDcars. The service allows residents to hire a car by the hour when they need one, thereby providing mobility insurance without needing to own a vehicle. To reduce the need to make regular car journeys to the supermarket, the development encourages the use of home delivery services from supermarket chains and local organic food suppliers. Residents have access to an Internet point and secure storage facilities for unattended deliveries. Choosing local and organic food reduces the typical household’s eco-footprint due to food consumption. The case study, then, exemplifies many of the approaches proposed by our shared vision on Green and Thriving Neighbourhoods, such as the need to create green and nature-based solutions, socially inclusive spaces and incentivize sustainable lifestyles. 

A Net Zero Pathway Based on Reducing Embodied Energy, on Energy Efficiency, Systems Integration and Circularity

BedZED achieves high standards in environmental performance through the implementation of three strategies: 

• Minimising embodied emissions.

• Designing the urban fabric and buildings with passive design techniques.

• Integrating energy systems at neighbourhood level

Minimising Embodied Emissions

Embodied emissions are emissions from the materials and construction processes of buildings and infrastructure, including new construction, retrofits and redevelopment. All embodied emissions should be assessed, including those due to material extraction, manufacturing, assembly, maintenance, repairs, replacements, deconstruction, demolition and any associated transport, waste and end of life impacts. We recommend setting an embodied emissions target for Green and Thriving Neighbourhoods. The neighbourhood should establish a process for requiring lifecycle emissions assessments from all construction. An ambitious target would be at least a 50% reduction over the ‘Business-as-usual’ approach. In BedZed, designers took great consideration of the development’s embodied energy. Construction materials were selected for their low-embodied energy and sourced within a 35-mile radius of the site when possible. The energy expended in transporting materials to the site was therefore minimised.

Designing the Urban Fabric and Buildings with Passive Design Techniques

BedZed uses passive solar techniques with houses arranged in south-facing terraces to maximise heat gain from the sun. Each terrace is backed by north-facing offices, where minimal solar gain reduces the tendency to overheat and the need for air conditioning.

Additionally, zoning of activities increases energy efficiency. The spaces for employment and community use are placed in the shadow zones of the housing terraces, this avoids the tendency for summer overheating of workspaces and the need for energy-wasting fan-driven ventilation or air conditioning. The workspaces are lit via large north-facing roof lights to ensure adequate daylighting and reduce the energy demand for artificial lighting. 

Insulation levels are considerably higher than those required by the Building Regulations. The buildings benefit from a 300 mm ‘overcoat’ of super-insulation to the roofs, walls and floors. This keeps in the warmth, so that sunshine, human activity, lights, appliances and hot water provide all the heating needed. High quantities of thermal mass provide enough heat storage to prevent overheating in the summer and to store warmth for slow release in the winter. Triple-glazed, krypton-filled windows with low-emissivity glass, large panes and timber frames further reduce heat loss. Well-sealed doors and windows give a good level of airtightness. Heat exchangers in the passive, wind-driven ventilation system recover up to 70% of the heat from the outgoing stale air.

Integrating Energy Systems at Neighbourhood Level

In BedZED the main source of energy is a Combined Heat and Power (CHP) plant which runs on chipped tree waste. The CHP has been sized so that over the course of a year it generates enough electricity to provide for all the development’s needs, this makes BedZED a zero-fossil energy development. Waste heat from electricity generation provides hot water for the homes and offices. It is distributed via a district heating system of insulated pipes. Water of constant temperature is delivered to oversized domestic hot water cylinders positioned in cupboards within each dwelling. The cupboards can be opened to double up as radiators in cold spells. Additionally, the homes are fitted with one small radiator and a heated towel rail. 

The CHP generator engine is fuelled by a combustible mix of hydrogen, carbon monoxide and methane gases, produced from woodchips by an on-site gasifier. These come from local tree waste which would otherwise go to landfill. The CHP is approximately 30% more efficient than conventional electricity generation as productive use is made of heat energy that would otherwise be wasted. Generating on-site also avoids the losses in transporting energy via the high-voltage National Grid. 

Photovoltaic panels allow electricity to be generated directly from the sun’s energy. The development boasts 777m2 of high-efficiency mono-crystalline PV panels integrated into the sunspace roofs and the CHP building.

The strategies implemented in BedZED are wholly aligned with the guidelines to reduce carbon emissions and achieve net zero through green buildings and energy. 

Lessons Learnt

The BedZED Development design meets very high environmental standards, with a strong emphasis on roof gardens, sunlight, solar energy, reduction of energy consumption, and waste water recycling. The project highlights how integrated solutions combining passive design strategies and systems integration and circularity are successful in meeting net zero targets. The development design promotes walking, cycling and use of public transport, reducing residents’ reliance on cars. BedZED employs state-of-the-art energy efficiency, with super-insulation, double and triple glazing and high levels of thermal mass. BedZED meets all its energy demands from renewable, carbon neutral sources, generated on site.

BedZED sustainability principles have been translated into practical strategies to reduce environmental impacts and create a highly liveable community. This project highlights the importance of early strategic thinking and commitment to providing integrated solutions to sustainable community development. Many of the lessons learned and techniques refined at BedZED are transferable to other projects, whether involving new build, refurbishment or successful community management through ongoing energy and water efficiency and waste reduction. As a model, BedZED can be tailored for different uses and locations. The core principles of local sourcing, integrated mixed-use development linked with solar design, district energy systems, renewable power, and maximising the community, economic and amenity values, are widely applicable.

Footnotes

[1] Brian Edwards (2001), 'Rough Guide to Sustainability', RIBA Publications, 1-3 Dufferin Street, London.

References

Going Green 2020. The Modern Eco Village | BedZED. Youtube.