In recent years, environmental sustainability prominently features in the agendas of policy-makers and practitioners of urban development. Part 1 of this article describes eco-neighborhood projects and innovative aspects of building construction. Part 2 discusses the implementation potential of eco-neighborhoods in Greece.
Environmentally responsible urban development
Green development projects are part of a growing trend across Europe and since the early 1990s forward-looking municipalities have focused on eco-friendly projects. Environmental agendas are now concerned with urban development and redevelopment through innovation in building construction and use of low-energy techniques and materials. In brief, environmentally responsible urban development seeks to combine quality of life with minimal resource consumption such as fossil fuels, energy, water, and valuable land.[i]
At an urban level, a high utilization of already built-up areas, re-use of existing sites within city limits, and increased usage of urban infrastructure (i.e. public transport, energy, services and communication networks) preserve the landscape and protect biodiversity while improving efficiency. Also, compact development helps reduce automobile carbon miles. In relatively dense, mixed-use environments, people can walk, ride bicycles or use public transit instead of cars [ii]. Furthermore an increased frequency of casual encounters makes neighborhoods livelier, particularly when population density is combined with well-designed public spaces and green areas that provide recreation opportunities and ensure good microclimate, air and soil quality, and protection from noise.
Innovation in technology further reduces resource consumption in urban development. The use of renewable energy sources, such as solar, wind, geothermal, hydroelectric, and biomass, minimizes CO2 emissions. Other energy efficient technologies are cogeneration units that reach 80% efficiency as opposed to 40-50% of typical power stations. District heating provides higher efficiency and better pollution control than localized boilers. Finally, combined approaches to energy, water, and waste management yield remarkable environmental and economic benefits.
Equally important to mention is a substantial savings in resources at the building level achieved through architectural design. Compact forms and smart building orientation can be combined with energy production installations such as solar collectors and photovoltaic panels, green roofs, advanced building materials. It is important to take into account all phases of a building’s life from construction to operation to demolition.[iii]
A few inspiring Eco-neighborhood projects
Growing interest in environmentally responsible urban development has materialized in an array of eco-friendly projects ranging in size and functional mix.
BedZED (Beddington Zero Energy Development) in Sutton near London, UK, is a pioneering yet widely known project designed by Bill Dunster and developed by BioRegional and The Peabody Trust in the years 2000-2002. It features 100 housing units and 2,500 m2 of office/commercial space. Its innovative design lies in combining south facing housing with north facing workspace to maximize passive solar gains, and combine high-density with amenity. Each dwelling has access to a sky garden or terrace. Environmentally innovative features include:
– Energy efficiency: South facing conservatories, triple glazing, super insulation and passive ventilation which reduce space heating by 80% as opposed to conventional homes.
– Low-impact construction: Most construction materials were sourced within a 50-mile radius of the site and underwent a rigorous specification process.
– Water efficiency: Rainwater collection and reuse, water efficient home appliances
– On-site energy production: 777m² of solar panels and a cogeneration (CHP) plant fuelled by wood chips (although the latter was not used due to technical application problems)
– Waste recycling facilities
– Eco-friendly transportation: Priority goes to electric and liquefied-petroleum-gas cars, car-sharing operator on-site
While BedZED has not achieved the zero fossil energy target, as was envisioned, it remains an exceptional reference project, not least because its market popularity has demonstrated how environmental innovation can be economically profitable.
Over the last 15 years, eco-projects have evolved from several houses to entire neighborhoods. But to realize them, it usually takes more than just a visionary developer. Take the example of Freiburg, Germany. Twenty years ago, the city introduced the “low-energy standard.” Every new property built on municipal land must consume less than 65 kWh/m2a on energy for heating. This was further reduced to 15 kWh/m2a in 2011. Furthermore, in order to promote green transportation, the city center was pedestrainised, cycling paths were built and the tram system was extended. Finally, two new neighborhoods were planned: Rieselfeld (70 hectares, 4,200 apartments, 11,000 residents, 1993-2011), and Quartier Vauban (41 hectares, 5,500 residents, 1997-2006). Both are relatively dense, mixed-use, pedestrian-friendly districts served by a frequent tram service, and feature on-site energy production and water management systems.
Quartier Vauban in particular is known for the proliferation of “passives houses” that consume no more than 15 kWh/m2a for heating purposes. While the construction cost was 3-10% higher from conventional houses, passive houses provide 30% cost savings in energy. Vauban also includes the “Solar Settlement”, an innovative demonstration project by Rolf Disch Architects; its “plus-energy houses” use only 15% of the energy required by the average home in Freiburg. Thanks to extensive photovoltaic installations they even produce 36 kWh/m2a of electricity which is fed to the grid. Heating costs amount to 150-200 Euros/year, 10% less than a conventional house.
Implementation of green features in the Rieselfeld and Vauban projects required a joint effort from the municipality, private developers, design professionals, and future inhabitants. Besides engaging in an environmentally conscious effort, long-term benefits for the residents include energy cost savings and a pleasant living situation, as witnessed by the number of young families that moved into the homes. Architects and engineers benefit from an increase in technical knowledge. Developers profit from a secure and forward-looking investment with infrastructure endorsed by the municipality. Finally the municipality benefits from a decreased need for future expansion of urban infrastructure and voter satisfaction.
Others recent eco-neighborhoods include:
– GWL-Terrein in Amsterdam, Holland (6 ha, 600 units, 1,400 residents, 1995-1998)
– Bo01 in Malmo, Sweden (25 ha, 1,000 units, 1,400 residents, 1996-2006)
– Greenwich Millennium Village (GMV) in London, UK (20 ha, 2,900 units, 1999-2014)
– Kronsberg in Hannover, Germany (150 ha, 6,000 units, 15,000 residents, 1995-)
– Solar City in Linz, Austria (60 ha, 1,300 units, 3,200 residents 1999-2005)
– Hammarby Sjöstad in Stockholm, Sweden (160 ha, 9,000 units, 35,000 residents, 400,000 m2 of office/commercial space, 1996-2020)
* the second part of this Article will be featured in August’s column..
[i] For a comprehensive collection of texts focusing on different aspects of sustainable urban development, see Wheeler, Stephen M., and Timothy Beatley, eds. Sustainable Urban Development Reader. 2nd ed. Routledge, 2008.
[ii] For an analysis of the benefits of compact urban development, see Newman, Dr. Peter, and Jeffrey R. Kenworthy. Sustainability and cities: overcoming automobile dependence. Island Press, 1999.
[iii] Energy consumption in buildings occurs in five phases: embodied energy corresponds to the manufacturing of building materials and components; grey energy is the energy used to transport materials from production plants to the building site; induced energy is the energy used in the actual construction of the building; operation energy is consumed for electricity, heating, hot water, and cooling, during the building’s occupied life (largest share); finally, demolition energy corresponds to the demolition process and potential recycling of building parts. Jones, D. L, J. Hudson, and T. Ando. Architecture and the environment: bioclimatic building design. Laurence King, 1998.