Numéro 103 Juillet 2007La ville dans la transition énergétique
Despite their willingness to do so, cities are finding it difficult to extend their experience with saving energy to all the areas they cover. This problem comes from different methods of approach. Making action on energy part of a general ideology, promoting new values, means designing new forms of project ownership adapted to this new urban action.
The compact city, presented as the solution to reducing greenhouse gas emissions, is not achievable. Other more realistic approaches need to be found : relocating homes close to jobs and active support for the development of biofuels. Private cars have become the main method of getting to work in periurban areas, and mobility is now a fundamental part of contemporary lifestyles.
While energy consumption in homes, and therefore greenhouse gas emissions, can be reduced fairly easily using insulation and renewable energies, less significant progress has been made with transport. The townhouse model for new housing developments will allow more compact city development. Solar roof panels can be used to power electric cars. Local councils have a major role to play in the energy transition.
Energy consumption by cities depends on how they are laid out. Is it possible to dictate this in cities undergoing very rapid growth? Using the TRANUS-SETU simulation model can reveal the effects of transport and planning policies on urban sprawl, and therefore on transport and energy. Liaison on land use and transport is essential if the growth of cities is to be controlled.
The fact that car use and urban sprawl have developed differently on different continents makes different approaches to reducing greenhouse gas emissions plausible : the technology option, in which car use is maintained ; the social option, in which public transport and traffic calming are encouraged ; and the hybrid option, which combines both approaches and seems to be the favoured option in Europe.
Little is known about the flows of materials used in the everyday life of a city, making it difficult to arrange recycling and reduce the amount of these materials. Various methods have been developed to find out. The Eurostat method is used here to assess the "metabolism" of Paris, distinguishing between the centre, and the first and second rings, in which there are different types of activity. Waste from construction and public works is by far the largest category.
Knowing what the flows of materials are through an area for the purpose of recycling outgoing materials and reducing incoming materials is an increasing preoccupation for municipal authorities. The authors were asked to do these calculations by the city of Lille. They also chose the method recommended by Eurostat. The method, which initially focuses on energy resources, highlighted potential for improvement of the recycling of construction materials.
Estimating the energy costs and greenhouse gas emissions of buildings is possible for old building stock using methods from urban morphology combined with knowledge of construction and thermal engineering. The energy question encourages us to develop a scientific approach to the existing building fabric, as a thermal study of buildings in Paris shows.
A study undertaken as part of PREBAT showed that some countries are focusing more on dramatically reducing energy consumption in buildings while others are seeking to substitute fossil energies for renewable energies, with the aim of maintaining social energy. This is particularly the case in the United States. Technological innovation cannot be divorced from its cultural integration into a chain of social players, which can only have coherence at local level even though these initiatives may be facilitated at national level.
Technical standards for insulation and energy-saving equipment developed for new buildings can only be adapted for old buildings on a case-by-case basis. Tradesmen play a key role in passing on information about the public funding available and the possible technologies. The National Agency for Home Improvement supports less well-off homeowners and tenants, whose needs are often greatest and whose homes, being the cheapest, are in the worst condition.
How has a situation of innovation recently developed, and how is it continuing to develop, as regards energy in the home? Tradesmen play a pivotal role in this change, in which the banks have recently become involved and which in some regions is being driven by the local authorities. The quality of tradesmen’s work is guaranteed by quality labels and training, but the training courses set up at pioneering sites have not been taken up widely enough by the public sector.
A survey of middle-class home-owning couples, concerned about keeping their finances under control, shows sustained interest in energy-saving practices, but with some gaps justified by the persistent search for comfort : a debate on the lifestyle habits of different generations is not called for ; rather, saving energy has to be negotiated on a case-by-case basis according to the benefit it can provide to everyday life.
Calls to save energy and for more moderate energy consumption are a response to the social difficulties of improving energy supplies to some areas through new high-voltage lines. Populations then become directly aware of their responsibility for the careful management of a resource usually presented as plentiful and for unlimited consumption, at public and festive activities. This change of course requires the constitution of governing bodies of multiple players capable of having an impact on consumers’ behaviour.
France has joined in the global policy to fight global warming and reduce energy use, despite the fact that its nuclear and hydroelectric programmes mean its electricity is largely clean. As far as transport is concerned, changing fuel will not be enough to reduce global warming ; in fact, distances need to be reduced by organising cities more rationally. Behaviour needs to be changed, in the home and generally, through appropriate social engineering measures. ADEME has defined an outline for these.
An analysis of unpaid energy bills reveals a wide variety of situations. Housing in poor condition and/or low incomes are the main causes. EDF’s energy welfare fund helps those most hard up, but it is housing improvement initiatives that deal with the fundamental issues. Will the new energy suppliers provide a welfare fund when their greatest concern is to make their prices attractive?
Sweden has already begun to create a competitive energy market. Consumers can choose between several suppliers whose prices change in line with climatic and economic factors that are difficult to control. Welfare support for low-income families is less likely to reach single people, many of whom already spend more than 10% of their income on energy and who are therefore, by European standards, living in energy poverty.
Nearly three million people in France are served by local energy companies that were not nationalised. Despite initially fearing liberalisation, they are now trying to become players in it. They are exploiting their close relationship with local councils, while developing their national representation within ANROC.
ICLEI, the international council for local environmental initiatives, and other international associations, have since 1991 been coordinating the efforts of pioneering cities. Plans have been drawn up to reduce CO2 emissions from cities. The desired energy decentralisation is more or less in step with national policies. A new green form of city planning is in the process of being invented ; Sweden and the Netherlands already have some exemplary practical implementations of it.
Measures to achieve greater energy efficiency are promoted on the ground by local councils. Sufficiently large councils have the technical and communication skills they need to do this. Small communities can benefit from the advice of specialist organisations. But many councillors are still reluctant to invest in this area.
Decentralisation has given cities a major role to play in mediating change, particularly technological change. They can interpret this role as part of a drive for modernisation for all, in the development of globalised local government ; they can also play it as a showcase function for large industrial groups and international organisations. Both perspectives are present in the Mayor of London’s investment in the hydrogen economy, and are acted out by the intermediaries he is obliged to go through.
The highly dispersed nature of cities in the United States consumes vast amounts of energy. Atmospheric pollution and urban heat islands are causing concern to residents and city councillors alike. Local elected representatives and state governments have taken the initiative on action to help the climate. The media is holding up a few cities, which have the highest profile in these policies, as icons, but many others are also going down the green building road.
At the turn of the century, energy as a force and power, and its concentration in modern cities lit by electricity, was a source of fascination for poets, artists and philosophers. A quick review of a few pioneering texts from this era actually shows a vision of energy as explosive and expansive, accompanied by a bleak, empty vision of the town.
Are we trying to escape from this duality when we now talk about "mastering" its use?