Eco-towns, eco-cities, residential space and defensible space

Overview

Eco-town or eco-city, how an eco-town relates to sustainability in environmental terms and defensible space.

What you need to know

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Questions from this subtopic

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1. 1

   What is an eco-town or eco-city?

   Model answer

   An eco-town or eco-city is a settlement, or a substantial new district, planned from the outset to minimise its environmental impact and to work socially, rather than being made greener afterwards. The defining features are very high building energy standards and low-carbon heat and power, a layout designed so that most daily needs are within walking distance, priority for walking, cycling and public transport over the car, water efficiency and sustainable drainage, waste minimisation and high recycling, a network of green space serving drainage and biodiversity as well as recreation, local employment and services, and a mix of housing types and tenures including affordable homes.

2. 2

   What design features would you expect to see on the plan of an eco-town, and how would it look?

   Model answer

   On the plan, a series of neighbourhoods each with a local centre containing a school, shop and community building within roughly a five to ten minute walk of every home. A public transport spine, bus or tram, running through the centres so no home is far from a stop, with the highest densities placed around the stops and densities falling towards the edge. Streets laid out to give homes good solar orientation, with terraces and apartments predominating over detached houses. A district heating plant or energy centre serving the denser areas. Green and blue corridors following the drainage lines, doubling as swales, ponds and wetlands for surface water and as walking and cycling routes and habitat. Allotments and community growing space. Employment land integrated rather than exiled to a bypass. Parking limited, grouped and overlooked rather than dominating frontages, with car club bays and charging points. And a clear, connected network of footpaths and cycle tracks that is more direct than the road network, so walking and cycling are the quickest way to move about.

3. 3

   Explain how an eco-town relates to sustainability in environmental terms.

   Model answer

   It reduces demand at the point where it is cheapest to reduce, that is at the design stage. Well-insulated, well-oriented buildings served by low-carbon heat cut energy use and emissions per household far below the average for existing stock. A compact, walkable layout with good public transport reduces car kilometres, so transport emissions, air pollution and land needed for roads and parking all fall. Sustainable drainage and green corridors reduce runoff and flood risk and provide habitat, and biodiversity can be increased relative to the intensively farmed land often replaced. Water efficiency, food waste collection and high recycling reduce resource use and waste. The saving is locked in for the life of the buildings, which is the main advantage of designing rather than retrofitting.

4. 4

   How does an eco-town relate to sustainability in social terms?

   Model answer

   Positively, if it delivers what is planned: affordable homes across a range of tenures and sizes, so the place is mixed rather than exclusive; schools, health care and shops within walking distance, which particularly benefits children, older residents and households without a car; safe, overlooked streets and generous accessible green space, with documented health benefits from walking, cycling and access to green space; and structures for residents to be involved in running the community facilities. The main social risk is the opposite outcome: if the jobs, the bus service and the school arrive years after the houses, residents drive out of the settlement for everything, the place becomes a car-dependent dormitory, and the higher build cost has bought neither low emissions nor a functioning community.

5. 5

   Evaluate eco-towns as a contribution to sustainability.

   Model answer

   In their favour, they demonstrate that much higher standards are achievable, and the standards they pioneer tend to migrate into building regulations and planning policy for everyone, which is arguably their largest effect. They can achieve genuine measured reductions in energy use, car use and water consumption per household, and they show how drainage, green space and transport can be planned as one system rather than separately. Against them, most are built on greenfield land, so the land take and habitat loss are real and the countryside is consumed; higher construction standards raise costs, which can reduce affordability or squeeze out the affordable housing contribution; the transport and employment elements are the parts most often delayed or dropped when viability is tested, and without them the scheme fails; residents' behaviour may not match the design, since a well-insulated home can be heated to a higher temperature and the savings partly eaten by that rebound; the numbers involved are tiny compared with the existing housing stock; and there is a persistent risk that a scheme with a few visible green features is marketed as an eco-town without the substance. The honest conclusion is that they are valuable as exemplars and as a way of raising mainstream standards, but that they cannot by themselves make a country's settlements sustainable.

6. 6

   Why might retrofitting an existing town be a more sustainable use of resources than building a new eco-town?

   Model answer

   Because the great majority of the buildings that will be in use in thirty years already exist, so most of the possible savings lie in improving them rather than in adding a small number of excellent new ones. Existing towns already have roads, sewers, schools and public transport, so no new infrastructure or land is consumed, and reusing a building retains the carbon already embodied in its materials, which new construction must spend again. Retrofit also reaches low-income households in the worst housing, tackling fuel poverty at the same time. The counter-arguments are that retrofit is technically difficult in older and listed buildings, that it is disruptive and hard to organise across thousands of individual owners, and that new housing has to be built somewhere for a growing number of households. In practice a sustainable strategy needs both, with the larger share of effort on the existing stock.

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