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Sustainable Cities and Society 4 (2012) 29– 34

Contents lists available at SciVerse ScienceDirect

Sustainable Cities and Society

j our nal ho me page: www.elsev ier .com/ locate /scs

rban policies and sustainable energy management

abrizio Cumo, Davide Astiaso Garcia, Laura Calcagnini, Fabrizio Cumo,lavio Rosa ∗, Adriana Scarlet Sferra

apienza University of Rome, Italy

r t i c l e i n f o

rticle history:eceived 12 May 2011eceived in revised form 29 February 2012ccepted 6 March 2012

eywords:ustainable urban planning

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 interdisciplinaryand holistic approach, is to experience the sustainable reshaping of the city considering a minimum coreof the larger city’s model, conventionally called the urban cell. The methodological approach aims toevaluate 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

rban cellsnergy balanceotential use of renewable energy sourcesnergy consumptions reduction

urban cell energy balance through innovation technology either with the use of renewable resources orin the final consumptions. The methodology was tested in a case study of a single urban cell. Since anyurban cell will have a different energy balance due to local characteristics and functions, an urban cellcan be added to a close one (generating a urban cells grid) in order to ensure a better energy balance fromthe addition of more than one urban cell. The project foresees the elaboration of tools and strategies forcitizen information, training them about energy sustainability, with special emphasis on young people.

. Introduction

The European Union is currently involved in the sensitizationf the Member States to promote, elaborate and carry out strate-ies and policies to increase the environmental sustainability inrban areas, consistent with the economic costs, in order to achieve,hrough urban quality, the main goal of raising quality of life stan-ards. With these objectives, the significant Bilateral Project of thexecutive Programme on Scientific and Technological Cooperationetween the Republic of Italy and the Kingdom of Sweden waso-funded for the years 2010–2013.

In this context this paper describes the first year results of theoURCE – Sustainable Urban Cells – research project, supported byhe Italian Ministry of Education, Universities and Research (MIUR).

Source bilateral project, related to the research area “Energy andnvironment: Sustainable Cities” and therefore focused on urbannergy issues. The research was jointly developed by the CIT-RA (Centro Interdisciplinare Territorio Edilizia Restauro Ambiente),apienza Università di Roma and the KTH Swedish Institute (Royalnstitute of Technology, School of Architecture and Built Environment,epartment of Urban Planning and Environment).

The research progress of the first year is published in: F. Cumoby) Sustainable Urban Cell, Quintily Ed., Rome, October 2011.

∗ Corresponding author.E-mail address: flavio.rosa@uniroma1.it (F. Rosa).

210-6707/$ – see front matter © 2012 Elsevier B.V. All rights reserved.oi:10.1016/j.scs.2012.03.003

© 2012 Elsevier B.V. All rights reserved.

The SoURCE bilateral project based on an interdisciplinary andholistic approach is focused on sustainable management and there-shaping of urban areas, considering the new European initia-tives like the JPI Urban Europe and in view of the renewable energypolicies 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 sustainablemanagement and policies for urban areas.

Urban areas are in fact the places where the on-going trans-formation of environment, society, economy and their compleximpacts become concrete, need to be managed and must be takeninto consideration for the present and the future generations.

Since 2007 the United Nations has declared that in 2010 over50% of the mankind will live in Urban areas and this is believedto increase to 70% by 2050 (United Nations, 2007). This is partic-ularly the situation in the European Union considering the highpopulation density in the majority of the Member States: accord-ing to the European Environment Agency, almost three quartersof European citizens live in urban areas today, and is expectedto increase to 80% by 2020 (EEA, 2009). Acknowledging this factas a Major Society Challenge for the EU, the new mechanism ofthe Joint Programming Initiatives (JPI) of the European researchhas recently launched an initiative dedicated to that specific mat-ter, entitled “Urban Europe”, focused on how the Commission,

together with Member States will address the challenging subjectof the future of European urban areas, towards the next frame-work programme of the European research (starting from 2013),and in consideration of the new EU 2020 strategy that targets

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he future of the EU towards a smart, sustainable, and inclusiverowth.

The research project is related to an energy proposal for thenalysis and evaluation of the urban areas considering the urbanreas as the places for sustainable regeneration of energy flows:rom nature to city, from city to city and from city to nature. Thisesearch considers a minimal core of a city – the urban cell, on whicho apply the principles of upgrading energy and environment, butannot be considered as the only solution to solve the land planningssue, given the complexity of the several circumstances or aspectsnvolved to improve the quality of life.

The first year of this research is focused on an “energy vision”f urban areas, considering each place as natural resources inputsn contrast to the local human activities. Bearing this in mind, thepecific goals of this research programme are:

to handle the urban sustainability by contributing to urban plan-ning, providing practical guidelines and policies in order tore-shape urban areas through the identification of a minimumcore called the “urban cell”;to optimise the balance between the potential use of renewableenergy sources and power consumption in relation to the varioustypes of urban settlements;to assess and manage energy grids, for the optimisation of theenergy ratio between production and consumption in any indi-vidual cell.

The long-term goal is to experience the “sustainable reshapingf the city” considering the urban cell as the main essence of a largerity model.

Therefore, the research results will include practical guideliness a useful tool to help local administrations and decision makersn energy management to achieve a sustainable urban planning.n particular, we foresee that the Public Administration will useur guidelines to obtain National and European funds in order tomprove sustainability and quality of the urban cells within theirerritory.

The research also includes the involvement of the interest par-ies in order to test the real urban cell territorial applicability inerms of technical, administrative and economic aspects, provid-ng them with the sustainable skills and useful information to besed as an awareness campaign meant specially for young citizen’sGrenelle, 2009).

The SoURCE project schedules the analysis of the several char-cteristics that contributes to the quality of life, the environmentalustainability and the urban quality for an urban cell. None ofhe above-mentioned characteristics, made up of several topics, is

ore important than the others and none of them should be in aeadership role for the whole land planning and management inter-entions. Accordingly, every topic should be dealt with a subsidiarynd synergy approach. In fact, a research proposal related only tone topic, may well contribute to improve land development, butannot be considered as the only solution to solve the land planningssue, given the complexity of the several circumstances involvednto improving the quality of life.

. Methods

The research methodology aims to provide a standard procedureor the optimisation of energy efficiency through the application ofnnovation technologies either in the use of renewable resources

nd in the final consumptions. The methodological approach forhe achievement of this goal foresees an energy balance betweenhe potential use of renewable energy sources (Ep) and the energyonsumptions (Ec) falling within a territory.

nd Society 4 (2012) 29– 34

The energy balance is obtained considering the main the energytransformation systems and devices (best technologies, best useof traditional technologies, etc.), as well as tools for energy sav-ing (new and traditional technologies, best practices, etc.). Severalissues concerning costs, environmental impacts, policy constraints,stakeholders expectations.

The adopted strategies for natural energy optimisation andconsumption reduction are different for each urban area: best tech-nologies are not always applicable; moreover, different constraintsinfluence the territories. That is why this research methodology andits practical applications will have to pay attention to each spe-cific case, looking for the right solution also with the agreementof 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 territo-rial contexts, the scheme describes the research steps split in twopaths: one for the Ep assessment and the other one for the Ecassessment.

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 naturalscenarios which influences the Ep and Ec amounts.

With this aim, several territorial typologies have been assumeddepending on the natural scenario for Ep assessment and on theanthropic settlements for Ec assessment.

Concerning the natural scenario, the territorial classification hasbeen done using the following parameters: climate data, type ofsoil, hydro-geological characteristics and, comparable to these, theclean energy amounts coming from additional resource of humanactivities.

Concerning the anthropic settlements, for Ec assessment, theterritory 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 InformationSystem (GIS) database in order to allow a multi-layer territorialview.

2.2. Assessment of the potential use of renewable energy sources(Ep)

The potential use of renewable energy sources (Ep) is evalu-ated considering: primary energy amounts coming from naturalsustainable energy inputs (Er), clean energy amounts coming fromadditional resource of human activities (Ead), innovation tech-nology coefficient that can range on the basis of each energytransformation efficiency (˛), feasibility assessment of systemsimplementation and constraint analysis (F), cost/benefit analysis.

2.2.1. Analysis of primary energy amounts coming from naturalsustainable energy inputs (Er)

This first step is necessary for the identification of the differ-ent types of natural sustainable energy inputs in an urban contextand consequently to establish the different criteria for measur-ing the energy amounts of each considered energy typology. Thepotential use of Renewable Energy Sources (RES) depends on thenatural primary energy amounts coming from the following naturalsustainable energy resources: solar energy, wind power, geother-mal energy, biomasses, hydropower. The procedure foresees the

following steps:

• data survey (official references, scientific literature or local sur-vey);

F. Cumo et al. / Sustainable Cities and Society 4 (2012) 29– 34 31

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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 energyypologies will be estimated according to its universally recognizedquations and data will be collected by the official organisations.his virtual analysis and rating grid will be applied in a specificerritory, as case study, to quantify the energy amounts based onhe available data.

.2.2. Analysis of clean energy amounts coming from additionalesource of human origin (Ead)

In addition to the above mentioned RES, each territory has addi-ional energy resources that have to be considered to calculate thehole available clean energy potential Ep.

Therefore, this second step is necessary in order to identify allhe different sustainable inputs coming from human activities in arban area, and furthermore, to set up the measurement criteria ofnergy amounts for any analysed resource. This potential mainlyepends on human local characteristics and specificities such ashe reuse of retrievable energy coming from anthropic processes,ystems, organic products and discards. The procedure foresees theollowing steps:

data survey of local resource;data conversion of the energy amounts from additional resourceof human origin expressed in each specific units;sizing of the global usable amount of energy.

Moreover, this virtual analysis and rating grid will be appliedn the same specific territory analysed for the quantification of therimary energy amounts.

nergy balance evaluation.

2.2.3. Optimisation of energy processing coming from natural andadditional resources through the use of innovation technology (˛)

In this step we analyse: innovative systems and devices forenergy collection and transformation, innovative use of tradi-tional systems, mix of innovative and traditional systems, newtrends for technology transfer, current technological innovationsand research studies, time for their utilization, eventual limits andfurther additional potentialities.

2.2.4. Feasibility assessment of systems implementation andconstraint analysis (F)

Once we get the clean energy quantities potentially producedusing the natural primary energy amounts coming from naturalsustainable energy inputs (Er) as well as the additional energyamounts coming from the human activities, it will be possible toestimate which percentage of these quantities is actually obtainedthrough the effective territorial application of the technologiesand facilities required. In fact, the utilisation of the renewablenatural energy sources should necessarily be preceded by a ter-ritorial analysis to assess the practical feasibility of the systemsimplementation. Generally, the main impediments derive fromenvironmental, landscaping and historical constraints of the ana-lysed area as well as from environmental and landscaping impactsassociated with the construction, functioning and decommission-ing of the systems. Moreover, stakeholders interests and the propermorphological and building characteristics of the analysed urbancontext must also be considered.

Additionally, the urban cell has to fit with the minimum admin-istrative 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 specificurban cell, the analysis of the local constraints and feasibility willbe unavoidable.

3 ities and Society 4 (2012) 29– 34

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.2.5. Cost/benefit analysisThe cost analysis will be carried out by using the life cycle

pproach, through the human activity impact evaluation relatedo the energy and raw material consumption and to the pollutingmission. Both the LCA (Life Cycle Assessment) and the LCC (Lifeycle Cost) analysis are used for the rating of ecosystem and humanealth damages and impacts.

These methods will be related to other economic tools such asnancial sources, funding and occupation.

.3. Assessment of the energy consumptions (Ec)

In order to analyse the building and population density, the landse, and the urban morphology of an urban area, an outline of theata collection procedure will be developed to allow the estimationf energy consumption (Galli, 2007). The energy consumptions (Ec)s evaluated considering:

primary energy requirements for heating, cooling, lighting;innovation technology coefficient that can range on the basis ofeach energy transformation efficiency (ˇ);cost/benefit analysis.

.3.1. The reduction of energy consumption through best practicend available technologies (ˇ)

In this step will be analysed the following items: innovative sys-ems for building energy reduction, innovative use of traditionalystems, mix of innovative and traditional systems, current techno-ogical innovations and research studies, time for their utilization.urthermore, citizen behaviour best practices will be considered inhat every previously informed citizen should put on use for energyuildings consumption minimization without any direct interven-ion on the building.

.3.2. Cost/benefit analysisThe cost/benefit analysis for the implementation of the above-

entioned innovation technologies for energy consumptionsinimization will follow the same principles described in the

omonymous step for Ep assessment (cf. Section 2.2.5).

.4. Energy balance Ep vs Ec

After the Ep and Ec evaluation we have to compare these twonergy parameters through an energy balance. The Ep and Ec bal-nce have to be applied in a territory that we call “urban cell”. Sinceny urban cell will have a different energy balance due to local char-cteristics and functions, an urban cell can be added to a close onegenerating a urban cells grid) in order to guarantee a better energyalance from the addition of more than one urban cells.

. Case study

In order to validate the described methodology, we develop aase study, taking an area as object for calculation of the energyalance, conventionally called urban cell. This area had features for

meaningful exemplification and its results could be generalized,ithin certain limits, to other areas.

In order to select the urban cell, all the possible configurationsf a given territory were taken into account and classified.

Therefore, under this classification, we tried to select an urbanrea that did not involve difficulties in its analysis and in the result-ng resolving proposals, since the objectives of this research did not

llow it.

We selected a territory without atypical features, averagely pop-lated (about 1900–2100 inhabitants), mainly residential, with sizef approximately 8.50 ha.

Fig. 2. Case study area.

This territory is located in the Province of Rome, in the cli-mate zone D according to the Italian legislative classification (D.P.R.26/08/1993 n. 412: municipalities with a number of degree-daysgreater than 1400 and not exceeding 2100), longitude 12◦29′E, lati-tude 41◦53′N, solar radiation: 1517 kWh/m2 on flat surface exposedto the south and 1693 kWh/m2 on sloping surface exposed to thesouth (Fig. 2).

In carrying out the case study, according to the research objec-tives, it was considered reasonable to investigate only some aspectsof the case study, so that the findings even if partial were punctualand extensible to other contexts.

We considered it important to analyse:

• among the possible RES (Renewable Energy Sources) in the ter-ritory, the resource “sun” because is one of the most widespreadtechnology and one of the most funded in Italy (with biomass)(Enea, 2011);

• regarding the energy consumption assessment, reference wasmade to residential buildings, because the estimation methodsare consolidated. Moreover the residential sector, as a rule repre-sents between 50 and 55% of building typologies on the territory,it has been also taken into account that these building typologieshave a wide margin of action to reduce energy consumption;

• considering the energy consumption the winter heating sectorhas been exclusively analysed, since its incidence is particularlyrelevant. In Italy, the energy consumed for heating and domestichot water in residential buildings represents approximately 30%of national energy consumption, and 25% of the total nationalemissions of carbon dioxide (Enea, 2010).

Having limited the field of interest to the above mentioned ele-ments means that the testing is to be evaluated to be fully reliable:(a) regarding energy consumptions, because it was assessed in anaccurate manner, on the field, considering each single building (orhomogeneous groups of buildings); (b) concerning solar energycapture, because it was carried out exploring all the available alter-native technologies; (c) regarding the feasibility, because the wholecomplex of the most significant constraints of the considered con-text has been analysed.

On the basis of the above considerations, it was possible toachieve an adequate data identification, data reading and datainterpretation.

Regarding energy consumption assessment, the examinedbuildings have the following characteristics:

Number of buildings (42), average number of storey (4), use-able floor area (about 47.000 m2), year of construction between1930 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 33

Table 1Urban cell energy flows.

Energy production from natural resources (kWh/year) Energy balance Energy consumption (kWh/year)

Ec

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20 × 106–24 × 106 1.5 × 106–2.5 × 106 35–42

uildings: 36%, three-storey buildings: 24%; two-storey buildings:3%; five-storey buildings: 7%), roof surface (14.700 m2 on which4% flat and 26% sloping), Number of inhabitants: about 2000, aver-ge apartment square meters: 70 m2, number of families: about70.

Concerning solar energy capture, the type of plants selected wasolycrystalline silicon (the efficiency is around 10–16%), with pan-ls of different sizes (1.0−1.2 and 0.8–0.9 m), the optimal locations 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 “cor-

rective” 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 consumedenergy (Ep vs Ec).

. Results and discussion

Concerning the currently consumed energy assessmentEccurrent), we get the following values for buildings built between:930 and 1950 (1.900.000–2.100.000 kWh/year), 1950 and975 (1.650.000–1.750.000 kWh/year), 1975 and 2000 (370.000–10.000 kWh/year), 2000 and 2002 (165.000–1750.000 kWh/year).

The calculation was made taking into account the standardnergy needs for heating relating to the period of construction andhe legislative rules at that time.

Considering the calculation of the energy that will be poten-ially captured throughout the urban cell (Er), we arrived athe following values: 16.501.926 kWh/year on flat surface and.470.646 kWh/year on sloping surface. This calculation wasssessed considering UNI EN ISO 15927-6.

Concerning the calculation of the energy consumption reduc-ion as a result of the “corrective” interventions on the buildingsEc), we arrived at a range of 14–16%; this calculation was assessedssuming to carry out one or more energy redevelopment inter-entions (frame replacement, thermal insulation of: walls, groundoors, roofs and walls replacement with ventilated ones, systemseplacement with high performance ones, installation of tempera-ure control valves, scheduled maintenance of systems) dependingn the building time of construction, the construction technique,he deterioration level, the historical constraints and the economicosts. All interventions involve the use of recycled non-toxic localaterials, with reduced environmental impact throughout their

ife cycle.Considering the calculation of the actually picked up energy Ep

Er·˛·F) using the selected photovoltaic technology, the 100% of thevailable roof area is equivalent to 1.450.000–1.550.000 kWh/yearn flat roof and 590.000–610.000 kWh/year on sloping roof; these

alues must be reduced by 30–35% due to: losses caused by theemperature (considering local outside temperature), losses causedy angular reflection effects, shadings, not optimal orientation, notquipped surfaces, planning and historical constraints.

Ec·ˇ Eccurrent

3.5 × 106–4.0 × 106 4.0 × 106–4.5 × 106

Considering the assessment of the balance between producedand consumed energy (Ep vs Ec), we arrived at the following result:the percentage of energy produced from renewable sources withrespect to consumption is 35–42%.

This result shows that, considering the current technologies andthe constraints of the urban areas, we can use only the 7.5% (1.5 mil-lion kWh/year) of the 20 million kWh/year that nature provides inthe form of solar radiation in the examined portion of the territory;this electric energy amount is useful to meet the 37% of build-ings energy consumptions (4.0 million kWh/year estimated); since12.5% of these consumptions can be avoided with some correctiveinterventions on the buildings, on a case by case basis, energy pro-duced from solar resource can supply 42% of energy requirements(Table 1).

It should be highlighted that all the above mentioned choiceshave been made by the need to make an in situ reliable test ofthe methodology and are only part of the more general researchobjective: to analyse the whole RES taking into account the multiplecharacteristics and uses (consumptions and constraints).

The extension of the analysis to the whole RES typologies andsystems installable on the territory will be therefore the subject ofthe research prosecution during the second year; while during thethird year of the research, since each urban cell will be characterizedby its own energy balance, it will consider the need to aggregatemultiple contiguous urban cells, in order to optimise these energybalances and achieve an overall balance and then analyse theirconnections in a smart grid.

It should however be underlined that authoritative studies andexperiments reported in the specific literature argue that nowa-days current technologies do not see able to guarantee the expectedresults in terms of equilibrium of the energy balance; instead, itseems more correct to set less optimistic goals, but actually achiev-able ones, such as the 30% reduction of the energy consumptionsfor building heating and cooling or 40% of the electricity productionfrom RES.

5. Conclusions

The expected outcomes of the research will be the elaboration ofguidelines, formats for policies and administrative tools to managethe territory through preliminary sustainable design. These toolscould be addressed for further request of EU contributions. Fur-thermore, a specific dissemination plan will be elaborated to informcitizens in order to help them understanding the local policies andpossibly contribute to the process. In particular the citizens targetare 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 foreseeseveral options:

1. Renew the technology process to increase the Ep (BAT Best Avail-able 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: citizennformation and training about energy sustainability and publicdministration services for the realization of infrastructures andssets for the community.

Since one of the research aims was to elaborate a method-logy for the assessment of the sustainable energy potentialityf an urban context and for the analysis of the most innovativeechnologies for the collection and transformation of this poten-iality, it appears that it will be possible to apply the research

ethodology to other themes involved in sustainable urbananagement.In fact, the research methodology is interchangeable to other

erritorial urban planning themes that, parallel to the energy mat-ers, aim at a sustainable life quality enhancement.

Assessing the overall work in progress, the following appro-riate characteristics essential for research work are taken intoonsideration:

originality and innovativeness in terms of scientific developmentof the research procedure;identification of the necessary interdisciplinary interconnec-tions; considering the multidisciplinary approach not only like

nd Society 4 (2012) 29– 34

a summation of specialists, but also putting the different skillsfor the adopted energy key of interpretation;

• methodological rigour and consistency between objectives,methods, tools and expected results;

• transferability and usability of the research results (guidelinesand youth information).

References

EEA – European Environment Agency. (2009). Ensuring quality of life in Europe’s citiesand towns. EEA Report No 5/2009. Luxembourg: Office for Official Publications ofthe 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: MancosuEditore.

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 JPIUrban Europe (last access April 2011).

United Nations. (2007). World urbanization prospects. The 2007 revision. New York:United Nations.