Sustainable City is an expression that refers to a city or urban unit that respects the principles of sustainable development and ecological urbanism, which seeks to simultaneously take into account the social, economic, environmental and cultural issues of urban planning for and with the inhabitants for example through a HQE architecture, by facilitating the modes of work and transport sober, by developing the efficiency from the point of view of the consumption of energies and the natural and renewable resources. These are often eco-cities or eco- districts seeking to reduce their ecological footprint by offsetting their impacts and tending to repay their ” ecological debt “.
Their governance is generally based on the principle of local Agenda 21, including modes of participatory democracy and sometimes a goal of energy self- sufficiency, even food. On a smaller scale, we talk about ecovillage.
This concept is supported by the UN and Europe, which through UNEP and the Committee of the Regions of Europe in 2012 under the ” Rio + 20 ” signed a partnership agreement for sustainable cities and regions.
The sustainable city aims for a high quality of life for everyone and everywhere. The social and access to services (education, culture, leisure, health, associative life, and especially housing) have a fundamental role, from a social mix perspective. An effort of ethics and solidarity must be made to promote access to housing, leisure and culture for people with low incomes, the disabled or the elderly. Through twinning and north-south or east-west cooperation, these “cities” can help spread and develop these concepts elsewhere in the world.
Increase and diversify the housing supply; The population is a difficult constraint to anticipate and manage for governance systems, but the sustainable city to answer reasons the needs of families and social diversity generally targets a diverse range housing (size, location, accessibility for disabled persons and persons elderly, private property, community or rental..), while aiming to reconcile the best living conditions with the advantages of an urban environment, to produce the conditions of a social welfare and social rise.
Social housing. They are not ghettos and they must be protected by ceilings and resources depending on the composition of households, to help people in real financial or social difficulties. The sustainable city is a place of urban innovation and the fight against exclusion; The most modest live alongside the better-off, enjoying the same living environment, the same access to culture, amenities and leisure. Sustainable de- growth projects can be experimented with or various support systems, eg for single mothers, large families, families wanting to live with an elderly person at home.
The sustainable city requires eco-responsible and enlightened citizens living in a fulfilling context and promoting good health. A cultural policy and an eco-citizen culture of sustainable development are one of the elements, through support, including financial support, to cultural institutions, thus promoting their influence. It aims to awaken children to art and culture at school, while respecting sustainable development. Culture and leisure offerings can make the city more attractive, but the classic concept of attractivenesscan itself be blamed (for reasons of ecological footprint and impact in terms of peri-urbanization) in favor of a more intangible radiation, for example via the Internet as a medium of culture. Access to all these activities is free or paid, depending on the activities and income of each, making culture and recreation accessible to all. Marine
Sustainable Recreation Education
Health, intellectual enrichment and quality of life are improved by cultural and sports facilities (HQE) such as cultural centers including libraries, media libraries, access to the Internet and a nearby Nature, this one being integrated in a green network such as discovery and environmental education materials). Show and exhibition venues contribute to the enrichment of everyone’s culture and the promotion of local talent or independent artists. Sports complexes (swimming pool, grounds and places of sports, of proximity and of nature) supplement these infrastructures.
In this context, the activities give up the practices of confrontation, competition, and denigration in favor of logics of exchanges, collaboratives and recognition of others and their values. These are hobbies based on meetings, constructive exchanges based on respect for others and on the contribution of differences that is taught at school for all (children, rich, poor or with reduced mobility must all be able to have access). The meetings develop emulation in a spirit of solidarity, and the non-sectarian and non-communitarian feeling of belonging to a community in the world, which is fundamental for social sustainability.
Associative and cooperative life
It is often highly developed and encouraged in sustainable city projects, for a harmony between all the populations and actors of the city. Many ecovillages and eco-neighborhoods have – upstream – an associative origin.
Associations and solidarity: The principle of solidarity is structural in the sustainable city that involves mutual support between generations and between people from different ethnic backgrounds. In structures reserved for this purpose, the inhabitants of the city meet to share their know-how, their opinions and in some cases help each other, for example: the elderly can share their expertise in cooking or cooking. sewing and the youngest guide them in computer science.
Associations and culture: To implement the cultural policy of the sustainable city, it is necessary to set up special structures, responsible for bringing together children, the elderly, people with reduced mobility, in a common approach within these places of residence. trades. These cultural associations organize events, such as concerts, theatrical performances or exhibitions, promoting openness to others with, for example: exhibitions of primitive African art associated with the cinema of foreign authors. Bringing together all citizens and making everyone involved in community life.
Principle of neutrality
He wants the city to be “neutral” (that is to say without negative impact, or with impacts reimbursed in terms of overall balance) vis-à-vis its local and global environment. It is a major issue and objective in a sustainable neighborhood (or city). It concerns energy consumption, but also all areas that have an impact on natural or human resources.
In a year, a French consumes an average of 3 tons of oil equivalent energy. However, simple and daily actions could reduce this consumption by half.
Lighting represents on average 15% of an electricity bill. To reduce its load, it is necessary to make the most of the daylight, turn off the lights in the empty rooms, and use low energy lamps.
Electric heating is one of the main items of household energy consumption; it accounts for nearly 40% of private consumption. To reduce this figure, it would be necessary, among others:
use thermostats and programming clocks on the radiators or the boiler (19 ° C are sufficient in a living room, 16 ° C in a room at night);
improve the insulation of walls and windows (double or triple glazing can significantly reduce heat loss).
use of Class A appliances. Standards have been established to classify appliances on a scale of A to F: Category A represents those with low consumption, and F those with the highest consumption;
turn off the appliances rather than leaving them in standby. In fact, appliances in standby account for almost 10% of all electricity consumption;
use the “eco” programs of washing machines or dishwashers;
use sunscreens such as shutters, sunshades, humidifiers…
There are of course alternatives to electric heating. But oil or gas heaters are also polluting. In recent years, alternatives have developed with heat pumps and geothermal energy. Thus, the reversible heating, or air / air heat pump can heat or cool a house by greatly reducing its energy consumption (we can remember the figure of 4 units of energy for 1 consumed).
In the sustainable neighborhood, houses must be able to assume their own energy consumption, or at least part of their consumption. To do this, they are built so as to self-energize: solar panels are installed on the roofs or on the facades, the rainwater is recovered to the maximum, the insulation is improved not to lose heating and so do not waste. The equipment provided is economic type, category A. Construction materials are non-polluting, recyclable, recovered…
Reduction or elimination of fossil fuel requirements
In 2002, nearly 90% of the world ‘s energy consumption came from fossil fuel (oil, natural gas, coal) or uranium deposits. However, these traditional sources of energy pose many problems that are urgently needed.
Fossil energies correspond to the energies that are produced from rocks derived from the fossilization of living things: oil, natural gas, and coal.
These energies are in limited quantity, so they are exhaustible. Yet, the consumption of these energies continues to grow. For example, as a result of the decline in oil reserves 6, exploitation becomes increasingly difficult and expensive, and this is reflected in the economy: the price of a barrel of oil exploded from 2003 to 2008, when third oil shock. The peak oil world approach and the prospect of oil depletion will make it urgent to find solutions to reduce our dependence on oil.
In addition, fossil fuels contribute massively to global warming by the phenomenon of ” greenhouse effect ” because of the CO2 that their combustion releases into the atmosphere while polluting it. These energy sources present major disaster risks: oil spills, explosions of gas pipelines…
These energies are expensive, pollute, exhaustible, and dangerous to health. This is why we must reduce its consumption as soon as possible.
Orientation on clean and renewable energies.
Clean energy or green energy is a source of energy that does not produce pollutants. The concept of clean energy is distinct from that of renewable energy: the fact that energy is being reconstituted does not imply that the waste from the exploitation of this energy disappears, nor the opposite. The sources of energy generally cited as clean energy are geothermal energy, wind energy, hydroelectric power, solar energy, biomass, tidal energy. These energies are generally those most used across countries and the least expensive. Moreover, they are also the best controlled. The cleanest energy is the energy that we do not consume, so we can speak of “negawatts”, which is a clean energy that produces no waste. For example, W against a fluorescent lamp of 20 W means saving 80 W. The replacement of this lamp generates 80 watts “less”, which corresponds to 80 Negawatts. The production of “negawatts” is made possible thanks to the development of energy efficiency and energy sobriety.
Renewable energy is a source of energy that renews itself quickly enough to be considered inexhaustible on a human scale. Renewable energies come from regular or constant natural phenomena caused by the stars, mainly the Sun (radiation), but also the Moon and the Earth (geothermal energy). The notion of renewable energy is often confused with that of clean energy. However, even if an energy can be both renewable and clean, some can only be classified in one of these categories. For example, solar photovoltaic is renewable but produces waste containing heavy metals while producing electricity from coal with CO2 sequestration approaches a clean energy but is not renewable.
Reducing the energy consumption of transport
Transport is about half of the total consumption of oil in the world. One study showed that dense cities are more energy-efficient 8. Indeed, the density of cities makes public transport more profitable, and decreases the average length of trips made by car. Thus, the main European cities are more energy efficient than the main American cities.
A sustainable neighborhood must favor public transport: indeed the use of buses, subways, trams is more ecological and more economical than the car. In addition, it empties overcrowded city centers. These modes of transport are very beneficial: they are much faster, because they have reserved lanes (example of TEOR in Rouen), more economical, because a bus trip costs less than a car trip (on the same distance), less polluting, because metropolises and trams are electric; they consume five times less energy per passenger than a car. They have many more benefits.
The car pollutes a lot. At equal average speed, aggressive driving can increase fuel consumption by 30 to 40 percent. The sustainable neighborhood must therefore encourage a smooth ride: it damages the engine less and consumes less fuel. The sustainable neighborhood can also offer to invest in clean vehicles: an electric car does not emit polluting gases, is silent and economical.
On a larger scale, people have to take the train rather than the car; on long journeys, it is this means of transport that is the least polluting, even if it is not the fastest.
Reducing water consumption
Every French person consumes on average 150 liters of water a day, and only 1% is drunk. In a sustainable neighborhood, this consumption could be divided by 2, up to 76 liters of water per day. This involves the pre-equipment of low-consumption appliances, which consume about 39 liters of water against 100 liters for traditional devices. Smaller baths and pressure reducers should be installed; dual flushes can save 11,000 liters per year per inhabitant. In a sustainable neighborhood, rainwater is used to its maximum: it is stored, then serve to feed the flushing and water gardens. In addition, this district must have its own sewage treatment plant: this avoids the unnecessary flow of water to a remote station, which will consume energy for nothing. Hot water is produced by energy, regardless of its origin. It is imperative not to allow the water to run out when not in use:18 liters of water, 12 bottles of a liter and a half. In addition, a thermostat setting of the water heater saves hot water.
Waste management based on selective sorting involves additional costs due to the complexity of the stages of collection and processing. Yet, in most cases, municipalities can successfully make a financially positive balance through the recovery of recyclable waste. The sorting of waste is a positive point in the protection of the environment: it makes it possible to preserve it, by using recycled materials, instead of looking for these same materials in nature. The third positive point of selective sorting is finally the empowerment of the citizen, who has a simple way to contribute to the good management of the community and the preservation of the environment, realizing that an individual gesture, as simple, can have global benefits.
Restore, protect and manage biodiversity
The sustainable city seeks to reduce its rate of waterproofing and increase the naturalness of the city by restoring a green network that connects green spaces. For this reason, it hosts a large number of natural flora and fauna, for reasons of landscape, microclimatic, air quality and ecological. Trees, bushes, hedges, plant fences, valleys, green spaces, but also walls and terraces or green roofsplay a major role; They beautify the city, and if they are sufficient, help offset CO2 emissions, for a ” neutral ” city in terms of carbon footprint, more breathable and more “harmless” for the Earth ‘s atmosphere. The environmental education can help, as well as the development of a fifteenth HQE target.
This objective of ” neutrality” (energetic and environmental) implies a particular development of the territory.
In a sustainable city, different economic objectives can be sought:
to ensure the long-term viability of local businesses;
develop short supply chains: local agriculture and direct sales, local ecomaterial companies…;
favor the installation of companies that are part of sustainable development (respect for the environment, social objectives, etc.). This objective can for example be reflected in the certification of companies, but also in their commitment to social reintegration;
to promote a fair trade, which ensures a correct income and a personal development (education, culture…) to all the actors of the sector and reduces the excessive margins of certain intermediaries.
In urban planning and architecture, the economic pillar of sustainable development leads to think the project in terms of overall cost: reduce the resources (energy, materials, water, soil…) necessary for the project throughout the life of the project, while optimizing the budget so that costs do not become excessive and maintaining a high quality objective.
Land use planning
Cities are confronted with urban sprawl and ecological and urban fragmentation phenomena. The proliferation of peripheral, bypass bypasses, urban crowns, favored by road development and peripheral shopping centers, the proliferation of leisure centers, the extension of activity zones, the search for an individual habitat in the countryside lead to a dispersed city, land-consuming and displacement generator. The call for renewable energy is not a unique or sufficient answer to all the damage done to the environment. Land-use planning needs to be rethought in today’s cities and in new ecovillage, as well as mobility.
Issues of urban density
Some densification is often needed, but the sustainable city rejects the Hong Kong model, as does the Los Angeles- type sprawl.
Against urban sprawl
This phenomenon is characterized by the development of urbanized surfaces on the outskirts of large cities: peri-urbanization. The further you get from the center, the lower the density of the building. Indeed, these new urban areas (mostly rural in the past) are characterized by suburban urbanization, which, of course, given the proliferation of detached houses and private gardens, occupies a much larger floor area than the one used. by apartment buildings or townhouses.
This habitat mode is at first glance attractive. It allows to stay close to the city and its assets, while enjoying a property a priori cheaper and more available. Households can afford to own a relatively large detached house with a large garden for the price of an apartment in the city. In addition, they are also looking for a more pleasant living environment, especially for their children, being closer to the countryside and fleeing the embarrassing clichés caused by the city center (noise, pollution, stress, aggression…).
However, peri-urbanization quickly shows its limits, both economically and in terms of quality of life, and even goes against the principles of sustainable development. The first criticism that can be made is the absence of social mix, housing estates being mainly occupied when they are sold by young couples with young children. In addition, the pavilions within a subdivision are similar, of identical size, they are addressed to people who have the same level of income and therefore belong to the same social category. The other consequences are directly related to the major problem of the concept, the very low density that it induces. It results in the creation of “dormitory towns”, which, moving the workplace away from the place of residence, considerably increases the phenomenon of “commuting” and all the consequences adjacent to it (traffic jams, longer car travel time….) The “car ownership rate” per household is much higher in peri-urban areas than for the national average1. Households have almost every two cars, even the least favored. This high rate is due to the increase in distances to travel, whether for work, for recreation or for refueling, making alternative transport (walking and cycling) less credible. In addition, the public transit system is less efficient in these cases. The mesh, distributed according to the number of users, is consequently more spaced than in the city center, increasing the distance between stops and stations and the residents’ homes. Users are therefore forced to walk for a while or to drive to the nearest station, which significantly increases travel time and discomfort. Today there is no mode of transport that competes with the car in suburban suburbs. These two previous consequences added to the low density, requires the construction of road infrastructures and communication networks much larger in number of inhabitants than the average, reducing more and more natural spaces, agricultural, forest or pastoral. Urbanization is responsible for the disappearance of 60,000 hectares of natural and agricultural land each year in France, according to the IFEN1.
Urban sprawl, which is very fashionable today and the low density it induces, is therefore in no way a valid answer in the development of a sustainable neighborhood. The solution lies in a higher density.
In search of a reasoned and controlled urban density
The “sustainable city” model favors urban density in order to save space and limit travel. This conception is based on notions of “short distance” city or “compact city”. No “ideal” urban density has been defined, but researchers and examples of sustainable neighborhoods that have already been realized, predict a relatively high density. The buildings are either buildings of a reasonable height (between 3 and 5 floors), or small houses, terraced, with a small garden.
This high density allows for greater mobility and better accessibility to services. A person who does not have a car in a city or a compact neighborhood will be able to access a much larger number of services than in a low-density city.
It does not mean an overbidding of the land use, which would result in a suppression of common places or relatively large spaces, not built, that allow to “breathe”, not to feel suffocated by the constructions.
On the contrary, so-called “public” places, are very present and also show a re-design to make them more pleasant to live. These public places, streets, pedestrian zones, public gardens, squares, play not only a social role favoring meetings and contact between individuals, but above all they allow people to be able to breathe fresh air, to change their minds, to walk about outside. They therefore partly compensate individual gardens. This solution avoids the spread of cities, and therefore the place taken by them on the campaign, reducing all artificial surfaces.
The cost of densifying public transport and increasing the quality of infrastructure in general is reduced by the lower quantity of the latter. We favor quality over quantity. And this allows for many energy savings, whether for building materials, or for operation. Take the example of public lighting: considering two cities that have the same number of inhabitants, electricity consumption will be much lower for a city of high density than for the one with low density. Indeed, the road network and the total area of the city to be illuminated will be much less important for the first.
Density, a background phenomenon that reveals its importance when it is well controlled, influences many other factors, mainly the mobility of individuals.
Mobility as an issue
Circulation flow: unavoidable phenomenon?
These flows are numerous and partly inevitable. The sustainable city seeks to limit their impacts, for example through a coherent layout of hubs, travel routes and a balanced offer of local services and public transport, as well as by developing new information technologies or NICTas an alternative when possible (teleworking and new communication technologies have not yet made it possible to significantly and effectively replace the physical concentration of individuals). Certain “sustainable cities” do not call into question these flows, considered as a basis and sign of the good economic and socio-cultural health of a city, and do not intend to suppress them. They seek to anticipate and organize them without limiting them, diversifying them or spreading them over time to make them more fluid and avoid any saturation.
The concentration of the same activity in a sector or neighborhood (business, commercial, residential, leisure, etc.) is generally refused or limited to avoid sectoring generating periodic, brutal and significant flows (ex.: commuting and associated traffic jams, with peak hour saturations, and empty hours during off-peak hours). A good location of housing and economic activities and service in the same environment (functional mix) limits these problems. It allows employees to quickly and easily earn their work on foot, by bikeor via public transport, avoiding too much centralization of the flows on some main axes. It is necessary to multiply and diversify the axes within a city to avoid any congestion. Several axes of average size are therefore preferable to a major axis.
Diversification of means of transport
The low urban sprawl facilitates non-motorized travel (cycling, walking, rollerblading..) and public transport. When everything is at hand, the use of the car can become marginal. The heavy use of public transport, which limits and replaces the traffic of private vehicles responsible for congestion, pollution and accidents, is favored by a more frequent and precise and balanced network and service, reducing the distance between home and station or with closest stop, and therefore the transport time. Bus and tramway have priority over the rest of the traffic; often benefiting from reserved lanes, they become more practical and faster than the use of the personal car (in city centers, average driving speed is 20 km / h in London, 18 km / h in Paris and 7 to 8 km / h in Athens). Despite a lower average speed, the bike is very advantageous for short trips, the latter being compensated by a near zero parking time and a risk of traffic jam nonexistent. All alternative transport including cycling, but also rollerblades, scooters can be encouraged, including bike paths and other cycle routes and greenways, fasteners and bike shelters. Neighborhoods without cars already exist as well as many pedestrian areas, also open to bicycles.
The question of traffic flows and urban density is a determining factor in the development of territories. In order to convince the population of the usefulness and the need to take public transport, this requires a real spatial planning policy, specifically designed to improve travel time and the efficiency of public transport. common. It is also necessary to put “sticks in the wheels” of cars, to curb its expansion.
In the concept of a sustainable city, the environment is no longer dissociated from urban planning projects, nor from the economic, cultural or social orientations of the city. This concern for integration takes into account development in the long term and in a global perspective. The city thought of as a human environment is gradually replacing the anti-urban prejudices of the first ecological approaches. Thus, in the fight against nuisances are added more cross-cutting themes: reconquest of public spaces, soft mobility, control of peri-urbanization, citizen participation…
However, in trying to reconcile the irreconcilable, the sustainable city may run up against insurmountable contradictions, the first of which is certainly to redensify cities without sacrificing access to nature. Another contradiction lies in the rather unequal character of access to the ecological resources of the city. New representations of space are needed to avoid these pitfalls. By its ability, not to erase the contradictions, but to put them in debate, the sustainable city has at least the merit of being a great lever for democratic innovation.
In addition, most analyzes of the “sustainable city” fail to consider two angles of reflection. First of all the notion of geographical scale. Indeed, is it technically feasible to apply the revenues of an eco-neighborhood to a mega-city that, by definition, has at least 10 million inhabitants? In fact, truly sustainable cities are generally small urban units of about 50,000 inhabitants, such as the slow cities of Italy.
Source from Wikipedia