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Urban policies and sustainable energy management
Sustainable Cities and Society 4 (2012) 29–34
Contents lists available at SciVerse ScienceDirect
Sustainable Cities and Society journal homepage: www.elsevier.com/locate/scs
Urban policies and sustainable energy management Fabrizio Cumo, Davide Astiaso Garcia, Laura Calcagnini, Fabrizio Cumo, Flavio Rosa ∗ , Adriana Scarlet Sferra Sapienza University of Rome, Italy
a r t i c l e
i n f o
Article history: Received 12 May 2011 Received in revised form 29 February 2012 Accepted 6 March 2012 Keywords: Sustainable urban planning Urban cells Energy balance Potential use of renewable energy sources Energy consumptions reduction
a b s t r a c t This paper describes the results of the first year of the SoURCE – Sustainable Urban Cells – research project. The project’s main objective, focused on sustainable management of urban areas from an interdisciplinary and holistic approach, is to experience the sustainable reshaping of the city considering a minimum core of the larger city’s model, conventionally called the urban cell. The methodological approach aims to evaluate and improve the energy flows from nature to city, from city to itself and from city to nature. The method seeks to provide a standard procedure to evaluate the performance and optimization of the urban cell energy balance through innovation technology either with the use of renewable resources or in the final consumptions. The methodology was tested in a case study of a single urban cell. Since any urban cell will have a different energy balance due to local characteristics and functions, an urban cell can be added to a close one (generating a urban cells grid) in order to ensure a better energy balance from the addition of more than one urban cell. The project foresees the elaboration of tools and strategies for citizen information, training them about energy sustainability, with special emphasis on young people. © 2012 Elsevier B.V. All rights reserved.
1. Introduction The European Union is currently involved in the sensitization of the Member States to promote, elaborate and carry out strategies and policies to increase the environmental sustainability in urban areas, consistent with the economic costs, in order to achieve, through urban quality, the main goal of raising quality of life standards. With these objectives, the significant Bilateral Project of the Executive Programme on Scientific and Technological Cooperation between the Republic of Italy and the Kingdom of Sweden was co-funded for the years 2010–2013. In this context this paper describes the first year results of the SoURCE – Sustainable Urban Cells – research project, supported by the Italian Ministry of Education, Universities and Research (MIUR). Source bilateral project, related to the research area “Energy and Environment: Sustainable Cities” and therefore focused on urban energy issues. The research was jointly developed by the CITERA (Centro Interdisciplinare Territorio Edilizia Restauro Ambiente), Sapienza Università di Roma and the KTH Swedish Institute (Royal Institute of Technology, School of Architecture and Built Environment, Department of Urban Planning and Environment). The research progress of the first year is published in: F. Cumo (by) Sustainable Urban Cell, Quintily Ed., Rome, October 2011.
∗ Corresponding author. E-mail address: fl[email protected] (F. Rosa). 2210-6707/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.scs.2012.03.003
The SoURCE bilateral project based on an interdisciplinary and holistic approach is focused on sustainable management and the re-shaping of urban areas, considering the new European initiatives like the JPI Urban Europe and in view of the renewable energy policies of the Europe 2020 Strategy (European Commission, 2010). According to the last Status Report of the JPI Urban Europe (JPI, 2011) this scientific research aims to improve tools for sustainable management and policies for urban areas. Urban areas are in fact the places where the on-going transformation of environment, society, economy and their complex impacts become concrete, need to be managed and must be taken into consideration for the present and the future generations. Since 2007 the United Nations has declared that in 2010 over 50% of the mankind will live in Urban areas and this is believed to increase to 70% by 2050 (United Nations, 2007). This is particularly the situation in the European Union considering the high population density in the majority of the Member States: according to the European Environment Agency, almost three quarters of European citizens live in urban areas today, and is expected to increase to 80% by 2020 (EEA, 2009). Acknowledging this fact as a Major Society Challenge for the EU, the new mechanism of the Joint Programming Initiatives (JPI) of the European research has recently launched an initiative dedicated to that specific matter, entitled “Urban Europe”, focused on how the Commission, together with Member States will address the challenging subject of the future of European urban areas, towards the next framework programme of the European research (starting from 2013), and in consideration of the new EU 2020 strategy that targets
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the future of the EU towards a smart, sustainable, and inclusive growth. The research project is related to an energy proposal for the analysis and evaluation of the urban areas considering the urban areas as the places for sustainable regeneration of energy flows: from nature to city, from city to city and from city to nature. This research considers a minimal core of a city – the urban cell, on which to apply the principles of upgrading energy and environment, but cannot be considered as the only solution to solve the land planning issue, given the complexity of the several circumstances or aspects involved to improve the quality of life. The first year of this research is focused on an “energy vision” of urban areas, considering each place as natural resources inputs in contrast to the local human activities. Bearing this in mind, the specific goals of this research programme are: • to handle the urban sustainability by contributing to urban planning, providing practical guidelines and policies in order to re-shape urban areas through the identification of a minimum core called the “urban cell”; • to optimise the balance between the potential use of renewable energy sources and power consumption in relation to the various types of urban settlements; • to assess and manage energy grids, for the optimisation of the energy ratio between production and consumption in any individual cell. The long-term goal is to experience the “sustainable reshaping of the city” considering the urban cell as the main essence of a larger city model. Therefore, the research results will include practical guidelines as a useful tool to help local administrations and decision makers in energy management to achieve a sustainable urban planning. In particular, we foresee that the Public Administration will use our guidelines to obtain National and European funds in order to improve sustainability and quality of the urban cells within their territory. The research also includes the involvement of the interest parties in order to test the real urban cell territorial applicability in terms of technical, administrative and economic aspects, providing them with the sustainable skills and useful information to be used as an awareness campaign meant specially for young citizen’s (Grenelle, 2009). The SoURCE project schedules the analysis of the several characteristics that contributes to the quality of life, the environmental sustainability and the urban quality for an urban cell. None of the above-mentioned characteristics, made up of several topics, is more important than the others and none of them should be in a leadership role for the whole land planning and management interventions. Accordingly, every topic should be dealt with a subsidiary and synergy approach. In fact, a research proposal related only to one topic, may well contribute to improve land development, but cannot be considered as the only solution to solve the land planning issue, given the complexity of the several circumstances involved into improving the quality of life. 2. Methods The research methodology aims to provide a standard procedure for the optimisation of energy efficiency through the application of innovation technologies either in the use of renewable resources and in the final consumptions. The methodological approach for the achievement of this goal foresees an energy balance between the potential use of renewable energy sources (Ep) and the energy consumptions (Ec) falling within a territory.
The energy balance is obtained considering the main the energy transformation systems and devices (best technologies, best use of traditional technologies, etc.), as well as tools for energy saving (new and traditional technologies, best practices, etc.). Several issues concerning costs, environmental impacts, policy constraints, stakeholders expectations. The adopted strategies for natural energy optimisation and consumption reduction are different for each urban area: best technologies are not always applicable; moreover, different constraints influence the territories. That is why this research methodology and its practical applications will have to pay attention to each specific case, looking for the right solution also with the agreement of the citizens. To do this, a new procedure is being elaborated, summarized in the following process scheme (Fig. 1). In order to evaluate the energy balance in different territorial contexts, the scheme describes the research steps split in two paths: one for the Ep assessment and the other one for the Ec assessment. 2.1. Territorial analysis (A) Ep and Ec evaluations must be applied to the same urban area, aside from its boundaries, but in relation to the human and natural scenarios which influences the Ep and Ec amounts. With this aim, several territorial typologies have been assumed depending on the natural scenario for Ep assessment and on the anthropic settlements for Ec assessment. Concerning the natural scenario, the territorial classification has been done using the following parameters: climate data, type of soil, hydro-geological characteristics and, comparable to these, the clean energy amounts coming from additional resource of human activities. Concerning the anthropic settlements, for Ec assessment, the territory classification has been done based on settlement density, use destination, shape of the city, population density and land use. These classifications will be recorded in a Geographic Information System (GIS) database in order to allow a multi-layer territorial view. 2.2. Assessment of the potential use of renewable energy sources (Ep) The potential use of renewable energy sources (Ep) is evaluated considering: primary energy amounts coming from natural sustainable energy inputs (Er), clean energy amounts coming from additional resource of human activities (Ead), innovation technology coefficient that can range on the basis of each energy transformation efficiency (˛), feasibility assessment of systems implementation and constraint analysis (F), cost/benefit analysis. 2.2.1. Analysis of primary energy amounts coming from natural sustainable energy inputs (Er) This first step is necessary for the identification of the different types of natural sustainable energy inputs in an urban context and consequently to establish the different criteria for measuring the energy amounts of each considered energy typology. The potential use of Renewable Energy Sources (RES) depends on the natural primary energy amounts coming from the following natural sustainable energy resources: solar energy, wind power, geothermal energy, biomasses, hydropower. The procedure foresees the following steps: • data survey (official references, scientific literature or local survey);
F. Cumo et al. / Sustainable Cities and Society 4 (2012) 29–34
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Fig. 1. Process scheme for the energy balance evaluation.
• data conversion of the energy amounts from renewable resource, expressed in each specific unit; • dimensioning of the global usable amount of energy. The energy amount suitable for all the above-mentioned energy typologies will be estimated according to its universally recognized equations and data will be collected by the official organisations. This virtual analysis and rating grid will be applied in a specific territory, as case study, to quantify the energy amounts based on the available data. 2.2.2. Analysis of clean energy amounts coming from additional resource of human origin (Ead) In addition to the above mentioned RES, each territory has additional energy resources that have to be considered to calculate the whole available clean energy potential Ep. Therefore, this second step is necessary in order to identify all the different sustainable inputs coming from human activities in a urban area, and furthermore, to set up the measurement criteria of energy amounts for any analysed resource. This potential mainly depends on human local characteristics and specificities such as the reuse of retrievable energy coming from anthropic processes, systems, organic products and discards. The procedure foresees the following steps: • data survey of local resource; • data conversion of the energy amounts from additional resource of human origin expressed in each specific units; • sizing of the global usable amount of energy. Moreover, this virtual analysis and rating grid will be applied in the same specific territory analysed for the quantification of the primary energy amounts.
2.2.3. Optimisation of energy processing coming from natural and additional resources through the use of innovation technology (˛) In this step we analyse: innovative systems and devices for energy collection and transformation, innovative use of traditional systems, mix of innovative and traditional systems, new trends for technology transfer, current technological innovations and research studies, time for their utilization, eventual limits and further additional potentialities.
2.2.4. Feasibility assessment of systems implementation and constraint analysis (F) Once we get the clean energy quantities potentially produced using the natural primary energy amounts coming from natural sustainable energy inputs (Er) as well as the additional energy amounts coming from the human activities, it will be possible to estimate which percentage of these quantities is actually obtained through the effective territorial application of the technologies and facilities required. In fact, the utilisation of the renewable natural energy sources should necessarily be preceded by a territorial analysis to assess the practical feasibility of the systems implementation. Generally, the main impediments derive from environmental, landscaping and historical constraints of the analysed area as well as from environmental and landscaping impacts associated with the construction, functioning and decommissioning of the systems. Moreover, stakeholders interests and the proper morphological and building characteristics of the analysed urban context must also be considered. Additionally, the urban cell has to fit with the minimum administrative boundary and/or with a territory management tool that could ascertain the feasibility of each project. Thereby, when all the procedures will be applied in a specific urban cell, the analysis of the local constraints and feasibility will be unavoidable.
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F. Cumo et al. / Sustainable Cities and Society 4 (2012) 29–34
2.2.5. Cost/benefit analysis The cost analysis will be carried out by using the life cycle approach, through the human activity impact evaluation related to the energy and raw material consumption and to the polluting emission. Both the LCA (Life Cycle Assessment) and the LCC (Life Cycle Cost) analysis are used for the rating of ecosystem and human health damages and impacts. These methods will be related to other economic tools such as financial sources, funding and occupation. 2.3. Assessment of the energy consumptions (Ec) In order to analyse the building and population density, the land use, and the urban morphology of an urban area, an outline of the data collection procedure will be developed to allow the estimation of energy consumption (Galli, 2007). The energy consumptions (Ec) is evaluated considering: • primary energy requirements for heating, cooling, lighting; • innovation technology coefficient that can range on the basis of each energy transformation efficiency (ˇ); • cost/benefit analysis. 2.3.1. The reduction of energy consumption through best practice and available technologies (ˇ) In this step will be analysed the following items: innovative systems for building energy reduction, innovative use of traditional systems, mix of innovative and traditional systems, current technological innovations and research studies, time for their utilization. Furthermore, citizen behaviour best practices will be considered in that every previously informed citizen should put on use for energy buildings consumption minimization without any direct intervention on the building. 2.3.2. Cost/benefit analysis The cost/benefit analysis for the implementation of the abovementioned innovation technologies for energy consumptions minimization will follow the same principles described in the homonymous step for Ep assessment (cf. Section 2.2.5). 2.4. Energy balance Ep vs Ec After the Ep and Ec evaluation we have to compare these two energy parameters through an energy balance. The Ep and Ec balance have to be applied in a territory that we call “urban cell”. Since any urban cell will have a different energy balance due to local characteristics and functions, an urban cell can be added to a close one (generating a urban cells grid) in order to guarantee a better energy balance from the addition of more than one urban cells. 3. Case study In order to validate the described methodology, we develop a case study, taking an area as object for calculation of the energy balance, conventionally called urban cell. This area had features for a meaningful exemplification and its results could be generalized, within certain limits, to other areas. In order to select the urban cell, all the possible configurations of a given territory were taken into account and classified. Therefore, under this classification, we tried to select an urban area that did not involve difficulties in its analysis and in the resulting resolving proposals, since the objectives of this research did not allow it. We selected a territory without atypical features, averagely populated (about 1900–2100 inhabitants), mainly residential, with size of approximately 8.50 ha.
Fig. 2. Case study area.
This territory is located in the Province of Rome, in the climate zone D according to the Italian legislative classification (D.P.R. 26/08/1993 n. 412: municipalities with a number of degree-days greater than 1400 and not exceeding 2100), longitude 12◦ 29 E, latitude 41◦ 53 N, solar radiation: 1517 kWh/m2 on flat surface exposed to the south and 1693 kWh/m2 on sloping surface exposed to the south (Fig. 2). In carrying out the case study, according to the research objectives, it was considered reasonable to investigate only some aspects of the case study, so that the findings even if partial were punctual and extensible to other contexts. We considered it important to analyse: • among the possible RES (Renewable Energy Sources) in the territory, the resource “sun” because is one of the most widespread technology and one of the most funded in Italy (with biomass) (Enea, 2011); • regarding the energy consumption assessment, reference was made to residential buildings, because the estimation methods are consolidated. Moreover the residential sector, as a rule represents between 50 and 55% of building typologies on the territory, it has been also taken into account that these building typologies have a wide margin of action to reduce energy consumption; • considering the energy consumption the winter heating sector has been exclusively analysed, since its incidence is particularly relevant. In Italy, the energy consumed for heating and domestic hot water in residential buildings represents approximately 30% of national energy consumption, and 25% of the total national emissions of carbon dioxide (Enea, 2010). Having limited the field of interest to the above mentioned elements means that the testing is to be evaluated to be fully reliable: (a) regarding energy consumptions, because it was assessed in an accurate manner, on the field, considering each single building (or homogeneous groups of buildings); (b) concerning solar energy capture, because it was carried out exploring all the available alternative technologies; (c) regarding the feasibility, because the whole complex of the most significant constraints of the considered context has been analysed. On the basis of the above considerations, it was possible to achieve an adequate data identification, data reading and data interpretation. Regarding energy consumption assessment, the examined buildings have the following characteristics: Number of buildings (42), average number of storey (4), useable floor area (about 47.000 m2 ), year of construction between 1930 and 2002: (1930–1950: 44%; 1950–1975: 23%; 1975–2000: 21%; 2000–2002: 12%), linear geometric configuration (four-storey
F. Cumo et al. / Sustainable Cities and Society 4 (2012) 29–34
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Table 1 Urban cell energy flows. Energy production from natural resources (kWh/year)
Energy balance
Energy consumption (kWh/year)
Er
Ep (Er·˛·F)
Ep vs. Ec
Ec·ˇ
Eccurrent
20 × 106 –24 × 106
1.5 × 106 –2.5 × 106
35–42%
3.5 × 106 –4.0 × 106
4.0 × 106 –4.5 × 106
buildings: 36%, three-storey buildings: 24%; two-storey buildings: 33%; five-storey buildings: 7%), roof surface (14.700 m2 on which 74% flat and 26% sloping), Number of inhabitants: about 2000, average apartment square meters: 70 m2 , number of families: about 670. Concerning solar energy capture, the type of plants selected was polycrystalline silicon (the efficiency is around 10–16%), with panels of different sizes (1.0−1.2 and 0.8–0.9 m), the optimal location is building-integrated and facing south. At this point we proceeded with: (a) currently consumed energy assessment (Eccurrent ); (b) calculation of the energy that will be potentially captured throughout the whole examined area (Er); (c) calculation of the consumption reduction as a result of the “corrective” interventions on the buildings (Ec); (d) calculation of the actually picked up energy through the best available technologies and within the existing constraints (Ep = Er·˛·F); (e) assessment of the balance between produced and consumed energy (Ep vs Ec). 4. Results and discussion Concerning the currently consumed energy assessment (Eccurrent ), we get the following values for buildings built between: 1930 and 1950 (1.900.000–2.100.000 kWh/year), 1950 and 1975 (1.650.000–1.750.000 kWh/year), 1975 and 2000 (370.000– 410.000 kWh/year), 2000 and 2002 (165.000–1750.000 kWh/year). The calculation was made taking into account the standard energy needs for heating relating to the period of construction and the legislative rules at that time. Considering the calculation of the energy that will be potentially captured throughout the urban cell (Er), we arrived at the following values: 16.501.926 kWh/year on flat surface and 6.470.646 kWh/year on sloping surface. This calculation was assessed considering UNI EN ISO 15927-6. Concerning the calculation of the energy consumption reduction as a result of the “corrective” interventions on the buildings (Ec), we arrived at a range of 14–16%; this calculation was assessed assuming to carry out one or more energy redevelopment interventions (frame replacement, thermal insulation of: walls, ground floors, roofs and walls replacement with ventilated ones, systems replacement with high performance ones, installation of temperature control valves, scheduled maintenance of systems) depending on the building time of construction, the construction technique, the deterioration level, the historical constraints and the economic costs. All interventions involve the use of recycled non-toxic local materials, with reduced environmental impact throughout their life cycle. Considering the calculation of the actually picked up energy Ep (Er·˛·F) using the selected photovoltaic technology, the 100% of the available roof area is equivalent to 1.450.000–1.550.000 kWh/year on flat roof and 590.000–610.000 kWh/year on sloping roof; these values must be reduced by 30–35% due to: losses caused by the temperature (considering local outside temperature), losses caused by angular reflection effects, shadings, not optimal orientation, not equipped surfaces, planning and historical constraints.
Considering the assessment of the balance between produced and consumed energy (Ep vs Ec), we arrived at the following result: the percentage of energy produced from renewable sources with respect to consumption is 35–42%. This result shows that, considering the current technologies and the constraints of the urban areas, we can use only the 7.5% (1.5 million kWh/year) of the 20 million kWh/year that nature provides in the form of solar radiation in the examined portion of the territory; this electric energy amount is useful to meet the 37% of buildings energy consumptions (4.0 million kWh/year estimated); since 12.5% of these consumptions can be avoided with some corrective interventions on the buildings, on a case by case basis, energy produced from solar resource can supply 42% of energy requirements (Table 1). It should be highlighted that all the above mentioned choices have been made by the need to make an in situ reliable test of the methodology and are only part of the more general research objective: to analyse the whole RES taking into account the multiple characteristics and uses (consumptions and constraints). The extension of the analysis to the whole RES typologies and systems installable on the territory will be therefore the subject of the research prosecution during the second year; while during the third year of the research, since each urban cell will be characterized by its own energy balance, it will consider the need to aggregate multiple contiguous urban cells, in order to optimise these energy balances and achieve an overall balance and then analyse their connections in a smart grid. It should however be underlined that authoritative studies and experiments reported in the specific literature argue that nowadays current technologies do not see able to guarantee the expected results in terms of equilibrium of the energy balance; instead, it seems more correct to set less optimistic goals, but actually achievable ones, such as the 30% reduction of the energy consumptions for building heating and cooling or 40% of the electricity production from RES.
5. Conclusions The expected outcomes of the research will be the elaboration of guidelines, formats for policies and administrative tools to manage the territory through preliminary sustainable design. These tools could be addressed for further request of EU contributions. Furthermore, a specific dissemination plan will be elaborated to inform citizens in order to help them understanding the local policies and possibly contribute to the process. In particular the citizens target are teenagers who will be informed through web services, TV ads, school competitions and comic magazines. To plan urban areas improving the Ep/Ec balance, we foresee several options: 1. Renew the technology process to increase the Ep (BAT Best Available Technologies, with a potential cost increase). 2. Reduce the energy consumption (Ec) working on the built areas (with a potential cost increase). 3. Delimitation of the territory of each urban cell. 4. Add different urban cells in order to raise the energy balance with the aim of a “zero” energy balance.
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In addition, other significant research outputs are: citizen information and training about energy sustainability and public administration services for the realization of infrastructures and assets for the community. Since one of the research aims was to elaborate a methodology for the assessment of the sustainable energy potentiality of an urban context and for the analysis of the most innovative technologies for the collection and transformation of this potentiality, it appears that it will be possible to apply the research methodology to other themes involved in sustainable urban management. In fact, the research methodology is interchangeable to other territorial urban planning themes that, parallel to the energy matters, aim at a sustainable life quality enhancement. Assessing the overall work in progress, the following appropriate characteristics essential for research work are taken into consideration: • originality and innovativeness in terms of scientific development of the research procedure; • identification of the necessary interdisciplinary interconnections; considering the multidisciplinary approach not only like
a summation of specialists, but also putting the different skills for the adopted energy key of interpretation; • methodological rigour and consistency between objectives, methods, tools and expected results; • transferability and usability of the research results (guidelines and youth information). References EEA – European Environment Agency. (2009). Ensuring quality of life in Europe’s cities and towns. EEA Report No 5/2009. Luxembourg: Office for Official Publications of the European Communities. Enea, Annex 53 (2010). Total energy use in buildings – Analysis and evaluation methods. Roma. Enea (2011). Politiche e misure nazionali sui cambiamenti climatici. Roma. European Commission (EC) (2010). COM/2010/2020 final. Communication from the Commission: Europe 2020: A strategy for smart, sustainable and inclusive growth. Brussels. Galli, G. (by) (2007). Nuovo Manuale Europeo di Bioarchitettura. Roma: Mancosu Editore. Grenelle de l’environnement (2009). Loi Grenelle 1 03/08/2009. France. JPI Urban Europe, Status Report March 2011. GPC document, from April 2011 on URL http://www.jpi-urbaneurope.eu/About JPI Urban EU/What is JPI Urban Europe (last access April 2011). United Nations. (2007). World urbanization prospects. The 2007 revision. New York: United Nations.
Contents lists available at SciVerse ScienceDirect
Sustainable Cities and Society journal homepage: www.elsevier.com/locate/scs
Urban policies and sustainable energy management Fabrizio Cumo, Davide Astiaso Garcia, Laura Calcagnini, Fabrizio Cumo, Flavio Rosa ∗ , Adriana Scarlet Sferra Sapienza University of Rome, Italy
a r t i c l e
i n f o
Article history: Received 12 May 2011 Received in revised form 29 February 2012 Accepted 6 March 2012 Keywords: Sustainable urban planning Urban cells Energy balance Potential use of renewable energy sources Energy consumptions reduction
a b s t r a c t This paper describes the results of the first year of the SoURCE – Sustainable Urban Cells – research project. The project’s main objective, focused on sustainable management of urban areas from an interdisciplinary and holistic approach, is to experience the sustainable reshaping of the city considering a minimum core of the larger city’s model, conventionally called the urban cell. The methodological approach aims to evaluate and improve the energy flows from nature to city, from city to itself and from city to nature. The method seeks to provide a standard procedure to evaluate the performance and optimization of the urban cell energy balance through innovation technology either with the use of renewable resources or in the final consumptions. The methodology was tested in a case study of a single urban cell. Since any urban cell will have a different energy balance due to local characteristics and functions, an urban cell can be added to a close one (generating a urban cells grid) in order to ensure a better energy balance from the addition of more than one urban cell. The project foresees the elaboration of tools and strategies for citizen information, training them about energy sustainability, with special emphasis on young people. © 2012 Elsevier B.V. All rights reserved.
1. Introduction The European Union is currently involved in the sensitization of the Member States to promote, elaborate and carry out strategies and policies to increase the environmental sustainability in urban areas, consistent with the economic costs, in order to achieve, through urban quality, the main goal of raising quality of life standards. With these objectives, the significant Bilateral Project of the Executive Programme on Scientific and Technological Cooperation between the Republic of Italy and the Kingdom of Sweden was co-funded for the years 2010–2013. In this context this paper describes the first year results of the SoURCE – Sustainable Urban Cells – research project, supported by the Italian Ministry of Education, Universities and Research (MIUR). Source bilateral project, related to the research area “Energy and Environment: Sustainable Cities” and therefore focused on urban energy issues. The research was jointly developed by the CITERA (Centro Interdisciplinare Territorio Edilizia Restauro Ambiente), Sapienza Università di Roma and the KTH Swedish Institute (Royal Institute of Technology, School of Architecture and Built Environment, Department of Urban Planning and Environment). The research progress of the first year is published in: F. Cumo (by) Sustainable Urban Cell, Quintily Ed., Rome, October 2011.
∗ Corresponding author. E-mail address: fl[email protected] (F. Rosa). 2210-6707/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.scs.2012.03.003
The SoURCE bilateral project based on an interdisciplinary and holistic approach is focused on sustainable management and the re-shaping of urban areas, considering the new European initiatives like the JPI Urban Europe and in view of the renewable energy policies of the Europe 2020 Strategy (European Commission, 2010). According to the last Status Report of the JPI Urban Europe (JPI, 2011) this scientific research aims to improve tools for sustainable management and policies for urban areas. Urban areas are in fact the places where the on-going transformation of environment, society, economy and their complex impacts become concrete, need to be managed and must be taken into consideration for the present and the future generations. Since 2007 the United Nations has declared that in 2010 over 50% of the mankind will live in Urban areas and this is believed to increase to 70% by 2050 (United Nations, 2007). This is particularly the situation in the European Union considering the high population density in the majority of the Member States: according to the European Environment Agency, almost three quarters of European citizens live in urban areas today, and is expected to increase to 80% by 2020 (EEA, 2009). Acknowledging this fact as a Major Society Challenge for the EU, the new mechanism of the Joint Programming Initiatives (JPI) of the European research has recently launched an initiative dedicated to that specific matter, entitled “Urban Europe”, focused on how the Commission, together with Member States will address the challenging subject of the future of European urban areas, towards the next framework programme of the European research (starting from 2013), and in consideration of the new EU 2020 strategy that targets
30
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the future of the EU towards a smart, sustainable, and inclusive growth. The research project is related to an energy proposal for the analysis and evaluation of the urban areas considering the urban areas as the places for sustainable regeneration of energy flows: from nature to city, from city to city and from city to nature. This research considers a minimal core of a city – the urban cell, on which to apply the principles of upgrading energy and environment, but cannot be considered as the only solution to solve the land planning issue, given the complexity of the several circumstances or aspects involved to improve the quality of life. The first year of this research is focused on an “energy vision” of urban areas, considering each place as natural resources inputs in contrast to the local human activities. Bearing this in mind, the specific goals of this research programme are: • to handle the urban sustainability by contributing to urban planning, providing practical guidelines and policies in order to re-shape urban areas through the identification of a minimum core called the “urban cell”; • to optimise the balance between the potential use of renewable energy sources and power consumption in relation to the various types of urban settlements; • to assess and manage energy grids, for the optimisation of the energy ratio between production and consumption in any individual cell. The long-term goal is to experience the “sustainable reshaping of the city” considering the urban cell as the main essence of a larger city model. Therefore, the research results will include practical guidelines as a useful tool to help local administrations and decision makers in energy management to achieve a sustainable urban planning. In particular, we foresee that the Public Administration will use our guidelines to obtain National and European funds in order to improve sustainability and quality of the urban cells within their territory. The research also includes the involvement of the interest parties in order to test the real urban cell territorial applicability in terms of technical, administrative and economic aspects, providing them with the sustainable skills and useful information to be used as an awareness campaign meant specially for young citizen’s (Grenelle, 2009). The SoURCE project schedules the analysis of the several characteristics that contributes to the quality of life, the environmental sustainability and the urban quality for an urban cell. None of the above-mentioned characteristics, made up of several topics, is more important than the others and none of them should be in a leadership role for the whole land planning and management interventions. Accordingly, every topic should be dealt with a subsidiary and synergy approach. In fact, a research proposal related only to one topic, may well contribute to improve land development, but cannot be considered as the only solution to solve the land planning issue, given the complexity of the several circumstances involved into improving the quality of life. 2. Methods The research methodology aims to provide a standard procedure for the optimisation of energy efficiency through the application of innovation technologies either in the use of renewable resources and in the final consumptions. The methodological approach for the achievement of this goal foresees an energy balance between the potential use of renewable energy sources (Ep) and the energy consumptions (Ec) falling within a territory.
The energy balance is obtained considering the main the energy transformation systems and devices (best technologies, best use of traditional technologies, etc.), as well as tools for energy saving (new and traditional technologies, best practices, etc.). Several issues concerning costs, environmental impacts, policy constraints, stakeholders expectations. The adopted strategies for natural energy optimisation and consumption reduction are different for each urban area: best technologies are not always applicable; moreover, different constraints influence the territories. That is why this research methodology and its practical applications will have to pay attention to each specific case, looking for the right solution also with the agreement of the citizens. To do this, a new procedure is being elaborated, summarized in the following process scheme (Fig. 1). In order to evaluate the energy balance in different territorial contexts, the scheme describes the research steps split in two paths: one for the Ep assessment and the other one for the Ec assessment. 2.1. Territorial analysis (A) Ep and Ec evaluations must be applied to the same urban area, aside from its boundaries, but in relation to the human and natural scenarios which influences the Ep and Ec amounts. With this aim, several territorial typologies have been assumed depending on the natural scenario for Ep assessment and on the anthropic settlements for Ec assessment. Concerning the natural scenario, the territorial classification has been done using the following parameters: climate data, type of soil, hydro-geological characteristics and, comparable to these, the clean energy amounts coming from additional resource of human activities. Concerning the anthropic settlements, for Ec assessment, the territory classification has been done based on settlement density, use destination, shape of the city, population density and land use. These classifications will be recorded in a Geographic Information System (GIS) database in order to allow a multi-layer territorial view. 2.2. Assessment of the potential use of renewable energy sources (Ep) The potential use of renewable energy sources (Ep) is evaluated considering: primary energy amounts coming from natural sustainable energy inputs (Er), clean energy amounts coming from additional resource of human activities (Ead), innovation technology coefficient that can range on the basis of each energy transformation efficiency (˛), feasibility assessment of systems implementation and constraint analysis (F), cost/benefit analysis. 2.2.1. Analysis of primary energy amounts coming from natural sustainable energy inputs (Er) This first step is necessary for the identification of the different types of natural sustainable energy inputs in an urban context and consequently to establish the different criteria for measuring the energy amounts of each considered energy typology. The potential use of Renewable Energy Sources (RES) depends on the natural primary energy amounts coming from the following natural sustainable energy resources: solar energy, wind power, geothermal energy, biomasses, hydropower. The procedure foresees the following steps: • data survey (official references, scientific literature or local survey);
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Fig. 1. Process scheme for the energy balance evaluation.
• data conversion of the energy amounts from renewable resource, expressed in each specific unit; • dimensioning of the global usable amount of energy. The energy amount suitable for all the above-mentioned energy typologies will be estimated according to its universally recognized equations and data will be collected by the official organisations. This virtual analysis and rating grid will be applied in a specific territory, as case study, to quantify the energy amounts based on the available data. 2.2.2. Analysis of clean energy amounts coming from additional resource of human origin (Ead) In addition to the above mentioned RES, each territory has additional energy resources that have to be considered to calculate the whole available clean energy potential Ep. Therefore, this second step is necessary in order to identify all the different sustainable inputs coming from human activities in a urban area, and furthermore, to set up the measurement criteria of energy amounts for any analysed resource. This potential mainly depends on human local characteristics and specificities such as the reuse of retrievable energy coming from anthropic processes, systems, organic products and discards. The procedure foresees the following steps: • data survey of local resource; • data conversion of the energy amounts from additional resource of human origin expressed in each specific units; • sizing of the global usable amount of energy. Moreover, this virtual analysis and rating grid will be applied in the same specific territory analysed for the quantification of the primary energy amounts.
2.2.3. Optimisation of energy processing coming from natural and additional resources through the use of innovation technology (˛) In this step we analyse: innovative systems and devices for energy collection and transformation, innovative use of traditional systems, mix of innovative and traditional systems, new trends for technology transfer, current technological innovations and research studies, time for their utilization, eventual limits and further additional potentialities.
2.2.4. Feasibility assessment of systems implementation and constraint analysis (F) Once we get the clean energy quantities potentially produced using the natural primary energy amounts coming from natural sustainable energy inputs (Er) as well as the additional energy amounts coming from the human activities, it will be possible to estimate which percentage of these quantities is actually obtained through the effective territorial application of the technologies and facilities required. In fact, the utilisation of the renewable natural energy sources should necessarily be preceded by a territorial analysis to assess the practical feasibility of the systems implementation. Generally, the main impediments derive from environmental, landscaping and historical constraints of the analysed area as well as from environmental and landscaping impacts associated with the construction, functioning and decommissioning of the systems. Moreover, stakeholders interests and the proper morphological and building characteristics of the analysed urban context must also be considered. Additionally, the urban cell has to fit with the minimum administrative boundary and/or with a territory management tool that could ascertain the feasibility of each project. Thereby, when all the procedures will be applied in a specific urban cell, the analysis of the local constraints and feasibility will be unavoidable.
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2.2.5. Cost/benefit analysis The cost analysis will be carried out by using the life cycle approach, through the human activity impact evaluation related to the energy and raw material consumption and to the polluting emission. Both the LCA (Life Cycle Assessment) and the LCC (Life Cycle Cost) analysis are used for the rating of ecosystem and human health damages and impacts. These methods will be related to other economic tools such as financial sources, funding and occupation. 2.3. Assessment of the energy consumptions (Ec) In order to analyse the building and population density, the land use, and the urban morphology of an urban area, an outline of the data collection procedure will be developed to allow the estimation of energy consumption (Galli, 2007). The energy consumptions (Ec) is evaluated considering: • primary energy requirements for heating, cooling, lighting; • innovation technology coefficient that can range on the basis of each energy transformation efficiency (ˇ); • cost/benefit analysis. 2.3.1. The reduction of energy consumption through best practice and available technologies (ˇ) In this step will be analysed the following items: innovative systems for building energy reduction, innovative use of traditional systems, mix of innovative and traditional systems, current technological innovations and research studies, time for their utilization. Furthermore, citizen behaviour best practices will be considered in that every previously informed citizen should put on use for energy buildings consumption minimization without any direct intervention on the building. 2.3.2. Cost/benefit analysis The cost/benefit analysis for the implementation of the abovementioned innovation technologies for energy consumptions minimization will follow the same principles described in the homonymous step for Ep assessment (cf. Section 2.2.5). 2.4. Energy balance Ep vs Ec After the Ep and Ec evaluation we have to compare these two energy parameters through an energy balance. The Ep and Ec balance have to be applied in a territory that we call “urban cell”. Since any urban cell will have a different energy balance due to local characteristics and functions, an urban cell can be added to a close one (generating a urban cells grid) in order to guarantee a better energy balance from the addition of more than one urban cells. 3. Case study In order to validate the described methodology, we develop a case study, taking an area as object for calculation of the energy balance, conventionally called urban cell. This area had features for a meaningful exemplification and its results could be generalized, within certain limits, to other areas. In order to select the urban cell, all the possible configurations of a given territory were taken into account and classified. Therefore, under this classification, we tried to select an urban area that did not involve difficulties in its analysis and in the resulting resolving proposals, since the objectives of this research did not allow it. We selected a territory without atypical features, averagely populated (about 1900–2100 inhabitants), mainly residential, with size of approximately 8.50 ha.
Fig. 2. Case study area.
This territory is located in the Province of Rome, in the climate zone D according to the Italian legislative classification (D.P.R. 26/08/1993 n. 412: municipalities with a number of degree-days greater than 1400 and not exceeding 2100), longitude 12◦ 29 E, latitude 41◦ 53 N, solar radiation: 1517 kWh/m2 on flat surface exposed to the south and 1693 kWh/m2 on sloping surface exposed to the south (Fig. 2). In carrying out the case study, according to the research objectives, it was considered reasonable to investigate only some aspects of the case study, so that the findings even if partial were punctual and extensible to other contexts. We considered it important to analyse: • among the possible RES (Renewable Energy Sources) in the territory, the resource “sun” because is one of the most widespread technology and one of the most funded in Italy (with biomass) (Enea, 2011); • regarding the energy consumption assessment, reference was made to residential buildings, because the estimation methods are consolidated. Moreover the residential sector, as a rule represents between 50 and 55% of building typologies on the territory, it has been also taken into account that these building typologies have a wide margin of action to reduce energy consumption; • considering the energy consumption the winter heating sector has been exclusively analysed, since its incidence is particularly relevant. In Italy, the energy consumed for heating and domestic hot water in residential buildings represents approximately 30% of national energy consumption, and 25% of the total national emissions of carbon dioxide (Enea, 2010). Having limited the field of interest to the above mentioned elements means that the testing is to be evaluated to be fully reliable: (a) regarding energy consumptions, because it was assessed in an accurate manner, on the field, considering each single building (or homogeneous groups of buildings); (b) concerning solar energy capture, because it was carried out exploring all the available alternative technologies; (c) regarding the feasibility, because the whole complex of the most significant constraints of the considered context has been analysed. On the basis of the above considerations, it was possible to achieve an adequate data identification, data reading and data interpretation. Regarding energy consumption assessment, the examined buildings have the following characteristics: Number of buildings (42), average number of storey (4), useable floor area (about 47.000 m2 ), year of construction between 1930 and 2002: (1930–1950: 44%; 1950–1975: 23%; 1975–2000: 21%; 2000–2002: 12%), linear geometric configuration (four-storey
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Table 1 Urban cell energy flows. Energy production from natural resources (kWh/year)
Energy balance
Energy consumption (kWh/year)
Er
Ep (Er·˛·F)
Ep vs. Ec
Ec·ˇ
Eccurrent
20 × 106 –24 × 106
1.5 × 106 –2.5 × 106
35–42%
3.5 × 106 –4.0 × 106
4.0 × 106 –4.5 × 106
buildings: 36%, three-storey buildings: 24%; two-storey buildings: 33%; five-storey buildings: 7%), roof surface (14.700 m2 on which 74% flat and 26% sloping), Number of inhabitants: about 2000, average apartment square meters: 70 m2 , number of families: about 670. Concerning solar energy capture, the type of plants selected was polycrystalline silicon (the efficiency is around 10–16%), with panels of different sizes (1.0−1.2 and 0.8–0.9 m), the optimal location is building-integrated and facing south. At this point we proceeded with: (a) currently consumed energy assessment (Eccurrent ); (b) calculation of the energy that will be potentially captured throughout the whole examined area (Er); (c) calculation of the consumption reduction as a result of the “corrective” interventions on the buildings (Ec); (d) calculation of the actually picked up energy through the best available technologies and within the existing constraints (Ep = Er·˛·F); (e) assessment of the balance between produced and consumed energy (Ep vs Ec). 4. Results and discussion Concerning the currently consumed energy assessment (Eccurrent ), we get the following values for buildings built between: 1930 and 1950 (1.900.000–2.100.000 kWh/year), 1950 and 1975 (1.650.000–1.750.000 kWh/year), 1975 and 2000 (370.000– 410.000 kWh/year), 2000 and 2002 (165.000–1750.000 kWh/year). The calculation was made taking into account the standard energy needs for heating relating to the period of construction and the legislative rules at that time. Considering the calculation of the energy that will be potentially captured throughout the urban cell (Er), we arrived at the following values: 16.501.926 kWh/year on flat surface and 6.470.646 kWh/year on sloping surface. This calculation was assessed considering UNI EN ISO 15927-6. Concerning the calculation of the energy consumption reduction as a result of the “corrective” interventions on the buildings (Ec), we arrived at a range of 14–16%; this calculation was assessed assuming to carry out one or more energy redevelopment interventions (frame replacement, thermal insulation of: walls, ground floors, roofs and walls replacement with ventilated ones, systems replacement with high performance ones, installation of temperature control valves, scheduled maintenance of systems) depending on the building time of construction, the construction technique, the deterioration level, the historical constraints and the economic costs. All interventions involve the use of recycled non-toxic local materials, with reduced environmental impact throughout their life cycle. Considering the calculation of the actually picked up energy Ep (Er·˛·F) using the selected photovoltaic technology, the 100% of the available roof area is equivalent to 1.450.000–1.550.000 kWh/year on flat roof and 590.000–610.000 kWh/year on sloping roof; these values must be reduced by 30–35% due to: losses caused by the temperature (considering local outside temperature), losses caused by angular reflection effects, shadings, not optimal orientation, not equipped surfaces, planning and historical constraints.
Considering the assessment of the balance between produced and consumed energy (Ep vs Ec), we arrived at the following result: the percentage of energy produced from renewable sources with respect to consumption is 35–42%. This result shows that, considering the current technologies and the constraints of the urban areas, we can use only the 7.5% (1.5 million kWh/year) of the 20 million kWh/year that nature provides in the form of solar radiation in the examined portion of the territory; this electric energy amount is useful to meet the 37% of buildings energy consumptions (4.0 million kWh/year estimated); since 12.5% of these consumptions can be avoided with some corrective interventions on the buildings, on a case by case basis, energy produced from solar resource can supply 42% of energy requirements (Table 1). It should be highlighted that all the above mentioned choices have been made by the need to make an in situ reliable test of the methodology and are only part of the more general research objective: to analyse the whole RES taking into account the multiple characteristics and uses (consumptions and constraints). The extension of the analysis to the whole RES typologies and systems installable on the territory will be therefore the subject of the research prosecution during the second year; while during the third year of the research, since each urban cell will be characterized by its own energy balance, it will consider the need to aggregate multiple contiguous urban cells, in order to optimise these energy balances and achieve an overall balance and then analyse their connections in a smart grid. It should however be underlined that authoritative studies and experiments reported in the specific literature argue that nowadays current technologies do not see able to guarantee the expected results in terms of equilibrium of the energy balance; instead, it seems more correct to set less optimistic goals, but actually achievable ones, such as the 30% reduction of the energy consumptions for building heating and cooling or 40% of the electricity production from RES.
5. Conclusions The expected outcomes of the research will be the elaboration of guidelines, formats for policies and administrative tools to manage the territory through preliminary sustainable design. These tools could be addressed for further request of EU contributions. Furthermore, a specific dissemination plan will be elaborated to inform citizens in order to help them understanding the local policies and possibly contribute to the process. In particular the citizens target are teenagers who will be informed through web services, TV ads, school competitions and comic magazines. To plan urban areas improving the Ep/Ec balance, we foresee several options: 1. Renew the technology process to increase the Ep (BAT Best Available Technologies, with a potential cost increase). 2. Reduce the energy consumption (Ec) working on the built areas (with a potential cost increase). 3. Delimitation of the territory of each urban cell. 4. Add different urban cells in order to raise the energy balance with the aim of a “zero” energy balance.
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In addition, other significant research outputs are: citizen information and training about energy sustainability and public administration services for the realization of infrastructures and assets for the community. Since one of the research aims was to elaborate a methodology for the assessment of the sustainable energy potentiality of an urban context and for the analysis of the most innovative technologies for the collection and transformation of this potentiality, it appears that it will be possible to apply the research methodology to other themes involved in sustainable urban management. In fact, the research methodology is interchangeable to other territorial urban planning themes that, parallel to the energy matters, aim at a sustainable life quality enhancement. Assessing the overall work in progress, the following appropriate characteristics essential for research work are taken into consideration: • originality and innovativeness in terms of scientific development of the research procedure; • identification of the necessary interdisciplinary interconnections; considering the multidisciplinary approach not only like
a summation of specialists, but also putting the different skills for the adopted energy key of interpretation; • methodological rigour and consistency between objectives, methods, tools and expected results; • transferability and usability of the research results (guidelines and youth information). References EEA – European Environment Agency. (2009). Ensuring quality of life in Europe’s cities and towns. EEA Report No 5/2009. Luxembourg: Office for Official Publications of the European Communities. Enea, Annex 53 (2010). Total energy use in buildings – Analysis and evaluation methods. Roma. Enea (2011). Politiche e misure nazionali sui cambiamenti climatici. Roma. European Commission (EC) (2010). COM/2010/2020 final. Communication from the Commission: Europe 2020: A strategy for smart, sustainable and inclusive growth. Brussels. Galli, G. (by) (2007). Nuovo Manuale Europeo di Bioarchitettura. Roma: Mancosu Editore. Grenelle de l’environnement (2009). Loi Grenelle 1 03/08/2009. France. JPI Urban Europe, Status Report March 2011. GPC document, from April 2011 on URL http://www.jpi-urbaneurope.eu/About JPI Urban EU/What is JPI Urban Europe (last access April 2011). United Nations. (2007). World urbanization prospects. The 2007 revision. New York: United Nations.