Catania: Integrating renewable energy use in urban renewal planning

Abstract:

The project in Catania aimed at integrating renewable energy uses in rehabilitation planning of a historic quarter in Catania. The aim was to reduce energy consumption and air pollution levels and to improve the bioclimatic conditions and general living comfort in the area while at the same time respecting architectural traditions and asthetic needs. The project was carried out as part of the EU APAS programme "Urban planning maximizing the use of renewable energies" from1995 to August 1996.

The project in Catania is an outstanding example for good practice in urban development for several reasons:

• the project chose a holistic approach which tries to adapt renewable energy technologies to local planning realities, not the other way around and, therefore, has good chances of producing lasting successes;
• the project stresses the needs of inhabitants and their physical comfort and thus tries to establish a counterweight to purely economic and traffic dominated development schemes common during the 1960s and 70s.
• it provides a useful tool for, and thus promotes, implementation of a national law to support the utilisation of renewable energy sources.

Concept and aims

The Catania project is one part of a EU-wide project on "Urban Planning Maximising the Use of Renewable Energies", which is carried out by several cooperating international partners from Communities of Europe for Renewable Energies (CERE), each contributing different sub-projects (cf. also under Actors and Structures). The project's aim is to develop databases and urban planning instruments for the application of renewable energy uses in urban settlements all over Europe. One of the main obstacles to renewable energy use in municipalities is intended to be tackled by this means: the discrepancy between high urban population densities and the low level of renewable energy source availability which precludes planners simply applying conventional supply-oriented concepts. Instead demand-oriented systems need to be considered requiring multi-factored, integrated approaches that are not as easily carried out. In the context of the project, expertise and experience in the field of development and application of environmentally acceptable energy technologies were assembled and further refined for application in municipal planning. As the ultimate goal, the problems of deteriorating environmental conditions in growing municipalities and increasing resource consumption levels were approached by the project and important steps towards the emission-free municipality were developed.

The project carried out by Catania responded to a common problem in European towns and cities: historical city centres are often characterised by urban decay due to processes of suburbanisation and general economic stress. Frequently, the necessity for modernisation and maintenance work to improve sanitation systems, living comfort and indoor climate conditions especially in old buildings has been ignored. As a result, in recent years many municipalities have laid down re-development and re-furbishment plans to revitalise their city centres. Especially in regions like Sicily, Italy, with a predominantly warm and sunny climate but also in Northern regions, renewable energy use for heating, cooling and lighting can play an important role in planning these rehabilitation schemes.

For structural and aesthetic reasons, the basic layout and design of urban blocks and buildings can usually not be altered/adapted to suit extended exploitation of renewable energy uses. Nevertheless, there is great potential for the utilisation of renewable energy which so far has remained largely untapped. Various applications of passive (such as bioclimatic architectural features) as well as active forms can considerably improve energy use patterns, save fossil and financial resources and contribute to pleasent indoor and outdoor climate conditions.

However, in order to maximise the use of these techniques in urban rehabilitation on a regular basis and in a large scale manner, a decisive pre-requisite is that renewable energy application is integrated in the urban planning process at the beginning. Therefore, the principal aim of the project in Catania was to develop a methodology for integrated renewable energy planning which is applicable under local and national planning requirements and conditions. This entailed assessing current architectural and landscaping features and energy use patterns, potential applications of renewable energy uses, their technical and economic feasibility, and developing criteria for renewable energy selection in the light of applicable regulations. Various solutions for aesthetic architectural integration and implementation which is as cost effective as possible are to be developed and discussed. To test the methodology, preliminary steps for a pilot project area were taken. Ultimately, the resulting methodology was intended to serve as a planning tool suited for wide spread diffusion and duplication in the Mediterranean.

Within the Italian context, the project in Catania can also be seen as an endeavour to develop a tool for implementing a national law. This law obliges local authorities to conduct feasibility studies for several specified renewable energy options in public buildings and to carry these out in cases in which amortisation periods are less than eight years (ten years in towns with more than 50,000 inhabitants). Among others, the renewable energy options to be studied include solar collectors where horizontal solar radiation is greater than 150 W/m2 and cogeneration plants in hospitals with more than 200 beds.

Actors and Structures

The project "Urban Planning Maximizing the Use of Renewable Energies" is part of the European Union, DG XII, APAS programme (APAS RENA-CT94-0026); it involved several European partners which are all members of Communities of Europe for Renewable Energies (CERE). It was coordinated by Saarbrücker Stadtwerke, Germany, and ran from January 1995 until August 1996. An integrating final report and a handbook for town planners, for which the coordinators analysed and evaluated results of the sub-projects, was published in August 1997. The other partners carrying out sub-projects were, in addition to the Municipality of Catania, the Energiebedrijf Amsterdam, the local authorities of Fiesole, Sesto Fiorentino, Instituto Tecnologico y de Energias Renovables in Tenerife, the Laboratory of Farm Structures at the Agricultural University of Athens and the Resource Research Unit in the School of Urban and Regional Studies of Sheffield Hallam University. Throughout the projects, the partners kept up regular exchange of experience and expertise. In some of the projects, independent national experts were involved.

The Catania sub-project was carried out by the Municipality of Catania as the principal actor. Participating in the investigations were specialists such as town planners, architects and energy experts. Furthermore regular contact was established to the coordinator and to expert participants from CERE.

Implementation

To integrate renewable energy use application in urban rehabilitation schemes, a basic methodology was developed which consists of the following sequence of (interrelated) steps:

1. Study of urban and architectural features, social and traditional conditions.
2. Assessment of renewable energy (RE) sources and exploitation potential.
3. Study of technical feasibility of possible RE techniques.
4. Assessment of energy requirements.
5. Selection of the suitable RE techniques.

To refine and validate this methodology, a pilot study for preliminary implementation was carried out. Based on the assumption that the majority of existing buildings can be classified into a few basic types typical of Mediterranean historical city centres, three different building types were chosen as sample units. They are all situated in the Antico Corso quarter in the heart of the historical centre of Catania:

• Lower class apartment buildings dating from the end of the 19th century. The houses consist of 3-4 storeys and are generally in poor sanitation and technical conditions;
• a historical public building, the monastery Ex Reclusorio della Purità, which is utilised as a junior high school. It is characterised by typical heavy masonry wall structure and by a large courtyard, originally used as a garden but now paved;
• a recent public building, the High School Spedalieri, with about 1000 students. It is a four- storey, reinforced concrete frame structure with a flat roof and without any open or green space surrounding it.

The investigation of the conditions of these three buildings was carried out with a view to the context of urban development needs and planning for the area. Planning was thus not exclusively focused on reducing fossil energy use in the respective buildings and their units. An important aspect was to effect microclimatic improvements which would benefit the indoor comfort and energy needs as well as the general living comfort in the area. For this purpose, past and future urban transformation processes were considered, e.g. impacts of traffic and parked cars on the microclimate were studied and measures designed to counter their negative effects. Generally, a guiding principle was to respect and utilise existing architectural structures and to avoid installation of plant (e.g. for ventilation) whereever possible. As a result, the investigation concentrated on the areas of domestic water heating, summertime indoor temperature regulation, space heating and use of daylight. The two renewable energy sources primarily considered were solar radiation and wind flows.

To implement the methodology outlined above, detailed and comprehensive input data were collected. They included information on renewable energy sources and potential, energy consumption and requirements, the social, traditional, architectural and urban characteristics and legal provisions. Next, a knowledge base was set up based on these data. It was supported by data processing programmes such as the PC version of SHADOWPACK, a programme for 3D analysis of shadows on facades in specific urban settings. Data collection on energy requirements for space conditioning was performed on the basis of ESP, a survey and simulation tool developed by ESRU in Glasgow, UK. Then, proposals for specific applications of different renewable energy techniques were put forward and their feasibility was tested. Criteria for the selection of techniques were architectural compatibility, social acceptance, technical feasibilty, cost effectiveness and environmental and visual impact.

Results

Results obtained from the investigation of the three building types showed a number of feasible applications of renewable energy.

Hot water and heating. In all three sample cases, due to high solar radiation values, exploitation in thermal collectors for water or space heating was selected for integration. This included water based systems as well as air distribution networks, both placed under glass roof tiles. Ventilation fans can be photovoltaic(PV)-fed, thus giving an air flow proportional to available solar irradiance. Pay-back periods of between 8 to 10 years make the application mandatory for the two public buildings. For application in the residential buildings incentives are needed.

Interior space cooling. Wind conditions at a low but steady flow of 2-3 m/s were determined to be favourable for natural ventilation systems if they are well driven. Together with measures to reduce solar radiation onto the building walls, they were considered sufficient to allow passive space cooling systems with only marginal support from ventilators. For these, existing architectural features like courtyards (as cold source) were utilised and new features added like automatically controlled and PV-fed fans and window shutters for radiation and lighting control. Calculations of the effects of green areas adjacent to building walls to filter radiation emitted from parked cars and streets showed surprising results: by planting grass, shrubs and trees, radiation could be lowered from 20.2 W/m2 down to 3.9 W/m2. This has favourable effects on radiation absorbed by building walls as well as local outdoor temperatures and amenity.

Some more general conclusions could be drawn from the investigation concerning the transformation of historical buildings in the course of time and with social change. These conclusions are based on the conviction that historical architecture was constructed in ways that integrated intricate and sophisticated systems of natural cooling, shading, lighting and ventilation. The resulting recommendations should therefore be helpful as general urban planning guidelines:

First, radical changes in the uses of historical buildings often cause over-crowding of the building which generates strong variations in temperatures, humidity and physical as well as psychological discomfort. This is particularly obvious in cases in which new floors are constructed and tall, large rooms are partitioned; glare, air stagnation and storage of hot air are unavoidable negative side- effects necessitating air conditioning and thus substantially increasing energy consumption. Respect should therefore be paid to original features and uses of historical buildings, and new functions should be as similar as possible to original functions.

Second, artificial lighting should be avoided and, if necessary, restricted to point sources adapted to specific tasks and ergonomic needs. This takes account of aesthetics and comfort needs and saves electricity.

Third, the convincingly positive effects green areas can have on microclimate and living comfort conditions should be taken advantage of in urban rehabilitation planning. This should especially be the case because of, and despite, the current domination of motorised traffic uses in public spaces. Furthermore, courtyards now barren should be planted as was historically the case to improve their cooling effects.

Fourth, technical modernisation and improvements to installations and facades should respect the historical architectural character of the buildings.

In summary, the methodology developed proved to be a coherent and effective guideline for the assessment of renewable energy applications in rehabilitation schemes. This holds true also when the specific historic, architectural and social contexts and uses of the buildings are taken into consideration. Thus, the methodology developed should have the potential to serve as a standardised procedure for the investigation of renewable energy uses in urban rehabilitation schemes.

Finance

The project had a total budget of 80.000 ECU, of which 50% was financed through the EU APAS programme. The remaining half was covered by the Municipality of Catania.

Source of Information

Commune di Catania 1997: Task 10, Integration of Renewable Energies in Rehabilitation Schemes of Cities, in: Stadtwerke Saarbrücken AG: Urban Planning Maximizing the Use of Renewable Energies, Part III: Detailed Task Reports, Final Report, Contract: APAS RENA-CT94-0026, April

Contact:

Cities:

Catania:

Catania is one of the largest Sicilian cities situated on the southern slope of Mt. Etna by the Mediterranean. Catania proper today has a population of 360,000. However, over the last few decades, population has decreased considerably due to outward movement to villages in the hinterland and new suburban settlements. The greater metropolitan area of Catania totals 800,000 inhabitants.

Catania's economy is shaped by its large sea port and extended railway connections which have made Catania an important trading centre. Moreover, it has a long tradition of well established manufacturing enterprises and industrial companies in all sectors. However, since the 1980s, Catania has suffered seriously from the persistant economic downturn which stopped the upward curve of general industrial and commercial growth since the post-war years.

Building stock and layout of historical Catania largely date from the late 17th century when the town had to be reconstructed after Mt. Etna erupted in 1693. The historical quarter of Catania was then given its urban character. In the 1960s, first attempts at urban refurbishment and reconstruction in the historical quarters were made which, however, failed to prevent urban deterioration and social decay. Therefore, the inner city of Catania contains a considerable amount of uninhabited buildings today and, according to the General Urban Plan currently up for Council approval, is due for large-scale refurbishment, restructuring and future re-utilisation.

Population:

Project was added at 12.08.1997
Project was changed at 12.08.1997

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