For the first time in world history, a majority of Earth’s people currently live in cities. Every day, thousands of people around the world uproot themselves to move from the countryside to the city or, more often, a shantytown or favela on the city’s outskirts. For better or worse, the future of humanity will be lived in urban areas. Bold, innovative solutions are necessary for the cities of the future to be more environmentally and socially sustainable. One “ecodistrict” in Sweden is attempting to address these interconnected issues in ways that future cities might emulate.
Hammarby Sjöstad (“Hammarby Lake City”) is a sustainable, mixed-use development adjacent to the Swedish city of Stockholm. The project presents a model of sustainability in its redevelopment of a declining industrial district into housing, commercial areas, and recreational
space. The unique features and strategies for sustainability at Hammarby include innovative transportation methods and urban planning; biogas production from waste; power generation from trash; installed photovoltaic arrays; solar hot water tubes; centralized vacuum tube recycling collection; storm water remediation; green roofs; brownfield cleanup; and public education about environmental issues.
Hammarby Sjöstad contains 11,000 apartments, housing an estimated 25,000 residents. There is a roughly even split between tenancy and tenant ownership. The development includes a comprehensive system of new public transport links, leisure facilities, municipal services, commercial entities, and green public spaces.
The Hammarby model is unique in its integration of energy, solid waste, water and wastewater for homes, offices and other activities. Planned as a blueprint for cities of the future, the system also incorporates stormwater, rainwater and meltwater. Domestic refuse is separated into different chutes and the various fractions are then transported by vacuum to containers at a central collecting station.
Sustainable public transportation is offered with electric trains, biogas powered buses, and commuter boats. Hammarby Sjöstad is served by a modern public transport system, the Tvärbanan light railway, along with new bus services and a ferry service on Hammarby Sjö lake, between the district’s southern and northern points. Car pools are open to residents and people working in the area.
Background and Partnerships
In the early 1990s, Stockholm’s City Planning Administration acknowledged that the city’s population was growing and would continue to grow into the next century. The 1999 city plan identified several areas across the city for development, most of which had once been industrial sites. To meet the growing demand for urban living, these developments were planned as extensions of the city rather than new suburbs.
Hammarby Sjöstad was initially intended to be an Olympic village for Stockholm’s bid for the 2004 summer Olympics. This waterfront neighborhood was previously dominated by small-scale industries in a rundown area with temporary corrugated iron buildings. The soil was heavily polluted and had to be cleaned before any construction could start.
Multiple parties have financed the project. The City of Stockholm partnered with 25 construction companies to build the district, with the latter providing 80% of the total cost. Additional funding comes from the Swedish Rail Administration and the Swedish Road Administration.
An Eco-Cycle of Sustainability: Water, Energy, and Waste
From the beginning, ambitious goals for sustainability were integrated into the design of Hammarby Sjöstad. This district has won international recognition for the integration of its infrastructure and its sustainable methods of managing water, energy, and waste.
The Hammarby model includes energy conservation measures with the goal of reducing heat consumption in half and using electricity more efficiently than in the rest of Sweden. The share of renewable energy used there is also much higher than the Swedish average, with the use of bioenergy and incineration of local waste producing both locally generated heat and co-generated electricity.
Planners have also implemented large-scale local wastewater and stormwater harvest and filtration. Wastewater is treated locally. The sludge produced by the treatment process is recycled and used for fertilizing farmland and forestry land. The waste releases biogas during processing. That biogas is used as fuel for vehicles such as buses, taxis and waste collection trucks, and to heat 1000 homes in the area.
Heat is extracted from the treated water in the treatment plant, which is then used for district heating. With temperatures ranging between 10°C and 20°C during the year, wastewater is highly suitable for both heat and cold extraction. During the summer, the cold water can be used for cooling. Rainwater infiltrates the ground directly or is drained off through canals.
The district’s numerous small canals are integrated into the design of the urban landscape. Some of the roofs were designed as green roofs that buffer much of the rainwater. Runoff from roads is captured separately and drained off to treatment pools before being allowed to infiltrate the ground. The Hammarby model proves that wastewater can be used in multiple ways and that rainwater can be returned to the natural cycle.
Residents are offered recycling stations and food waste collection for biogas production. All apartments are connected to the district heating system, and the household waste supplies fuel for the district heating plant. Biogas stoves have been installed In 900 of the apartments. Some apartments also have solar hot water. The sewage from all apartments is cleaned and used to produce locally used biogas.
A Model City for the Future?
Hammarby Sjöstad was designed not just as a housing development but as a comprehensive infrastructure project that might be replicated in other cities. The heating, transport and waste collection systems were designed to work in tandem to reduce the amount of energy and resources needed to maintain them in the long term. All planning applications in Stockholm are based on life-cycle cost analysis, and it is therefore easier to justify higher initial investments in better performing building design.
Nevertheless, the project continues to face several challenges. The City Planning Administration predicted that many of Hammarby Sjöstad’s residents would be older people, but when the apartment blocks were completed they found that most of the people moving in were young families. They responded to this challenge by increasing their planned provision for local schools and crèche facilities. The development has also failed to meet its target for car ownership. Still, almost 80 per cent of commutes are made by public transport, cycling, or walking. Some of those involved in the project believe that it might have been better to focus on reducing car usage instead of eliminating car ownership.
Hammarby Sjöstad has become an international example of sustainable urban planning. For example, It has inspired the design of Toronto’s Waterfront, London’s New Wembley and many cities in China and Thailand. These alternative models of urban planning present exciting possibilities for the developing of sustainable cities in the future.
Dagvatten canal © André Vaxelaire
Written by Ryan Moore