PAPER • OPEN ACCESS Incorporating user preferences in rooftop food-energy-water production through integrated sustainability assessment* To cite this article: Susana Toboso-Chavero et al 2021 Environ. Res. Commun. 3 065001 View the article online for updates and enhancements. This content was downloaded from IP address 81.172.61.247 on 15/07/2021 at 11:41 Environ. Res. Commun. 3 (2021) 065001 https://doi.org/10.1088/2515-7620/abffa5 PAPER Incorporating user preferences in rooftop food-energy-water production through integrated sustainability assessment* OPEN ACCESS RECEIVED 12 January 2021 Susana Toboso-Chavero1,2 , Cristina Madrid-López1 , Xavier Gabarrell Durany1,2 and REVISED 7 May 2021 Gara Villalba1,2,∗∗ 1 Sostenipra Research Group (2017 SGR 1683), Institute of Environmental Science and Technology (ICTA; «María de Maeztu» Units of ACCEPTED FOR PUBLICATION 10 May 2021 Excellence (CEX2019-000940-M)), Z Building, Universitat Autònoma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain PUBLISHED 1 June 2021 2 Department of Chemical, Biological and Environmental Engineering, Universitat Autònoma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain ∗∗ Author to whom any correspondence should be addressed. Original content from this work may be used under E-mail: Susana.Toboso@uab.cat, Cristina.Madrid@uab.cat, Xavier.Gabarrell@uab.cat and Gara.Villalba@uab.cat the terms of the Creative Commons Attribution 4.0 Keywords: urban agriculture, urban sustainability, farm to fork, energy and water poverty, public participation, citizen science licence. Supplementary material for this article is available online Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation Abstract and DOI. With the overall aim to design successful implementation strategies of food-energy-water production systems on urban roofs, we propose an integrated process that includes participatory processes and a multi-dimensional sustainability assessment of environmental, social and economic indicators. The proposed framework was applied to a typical housing estate in the Metropolitan Area of Barcelona made up of 201 buildings and 13,466 inhabitants and characterized by a high share of low-income families. We assess several future scenarios of joint electricity production (photovoltaic panels), vegetable production (through open-air farming and greenhouses), green roof implementation and rainwater harvesting and rank them according to non-participatory and participatory approaches. In general, there was a tendency for residents to choose strategies providing energy and water rather than the food production potential of rooftops. However, the environmental assessment indicated that the least impacting alternatives from a life cycle approach were those promoting vegetable production, meeting 42 to 56% of the residents’ fresh produce demand and reducing environmental impacts by 24 to 37 kg CO2eq m−2 of rooftop/year. Hence, we found that residents were mainly concerned with energy expenses and not so much with food insecurity, social cohesion or the impacts of long-distance supply chains. Our assessment supports urban sustainability and helps identify and breach the gap between scientific and user preferences in urban environmental proposals by informing and educating residents through a participatory integrated assessment. 1. Introduction Cities are implementing a range of climate action programmes to develop resilient and environmentally, socially and economically healthy communities in response to the United Nations’ Sustainable Development Goal (SDG) ‘sustainable cities and communities’ (Rosenzweig et al 2010, United Nations 2020). One key to sustainable urban areas, is the sustainable supply of food, energy, and water and the optimization of this supply based on their interconnectedness, normally referred to as the food-energy-water (FEW) nexus (Garcia and You 2016). Metropolises dominate the demand for these flows, although production normally occurs elsewhere, consuming two-thirds of the primary energy demanded (IEA 2015) and up to 70% of the food supply (FAO 2017). Equally relevant is accessibility for vulnerable populations and/or marginalised sites with limited * Discover how to benefit from urban rooftops implementing food, energy and water systems for self-sufficient cities. © 2021 The Author(s). Published by IOP Publishing Ltd Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al financial resources to guarantee equal access and prevent FEW insecurity at the urban scale (Newell and Ramaswami 2020). An emergent strategy for procuring FEW in cities with limited land availability that covers these premises is the use of rooftops to grow vegetables, produce energy or harvest rainwater, termed the roof mosaic. The roof mosaic tries to intertwine the different flows of these resources (FEW) and seeks synergies and interactions within urban areas, proposing partial self-sufficiency of these resources. We conducted an initial study that analysed the environmental impacts of this strategy’s adoption (Toboso-Chavero et al 2019) and a second study screened a municipality’s metabolic pattern to detect hotspots in FEW resource consumption (Toboso-Chavero et al 2021). Nonetheless, to implement this strategy effectively in complex systems such as cities, a more comprehensive and participatory framework has to be established (Kloepffer 2008). In the roof mosaic framework, a sustainability assessment that integrates complex environmental, social and economic values is crucial to ensure forward-looking sustainability assessment methodologies (Kloepffer 2008, Kühnen and Hahn 2019). Such assessments provide a ‘triple bottom line’ political background (environmental, social and economic), are proactive and not reactive, are multi-criteria and not single-issue, and are guided by a stakeholder-driven approach, characterised by being complex, multi-scalar, multi-dimensional and multi- disciplinary and focused on finding integrated solutions (Finkbeiner et al 2010, Zamagni 2012). As an overall trend, a large number of studies on the use of cities’ roofs focus their attention on only one pillar of sustainability, i.e., on the environmental aspects, calculating the environmental impacts and benefits (Cucchiella and Dadamo 2012, Lamnatou and Chemisana 2014, Bazán et al 2018, Sanjuan-Delmás et al 2018, Salvador et al 2019) or on the social aspects, exploring the social perception of the implementation of these systems on roofs (Cerón- Palma et al 2012, Specht et al 2016, Sanyé-Mengual et al 2016, Ercilla-Montserrat et al 2019, Zambrano-Prado et al 2021). Hence, efforts should be made to expand into a more integrated vision. In the same way, as pointed out by Newell and Ramaswami (2020), public participation is often omitted in the FEW nexus literature. Following this observation, the adoption of the roof mosaic must consider its human dimensions. Accordingly, ‘citizen science’, a label increasingly used to define the general public’s engagement in research activities (Strasser et al 2019) can lead to more democratic and open research and enhance science- society-policy interactions (European Commission 2014). Thus, giving voice to residents results in more effective research for the social acceptance of novel strategies (O’Faircheallaigh 2010). The International Association for Public Participation (IAP2) proposes a spectrum of public participation, with classifications for the lowest levels of participation, i.e., informing, to the highest level, i.e., empowering citizens (International Association of Public Participation 2020). Advances have been made in the integrated sustainability assessment community in this direction but in other contexts (e.g., natural resource management sectors) and using different methodologies (Pahl-Wostl 2002, Pahl-Wostl and Hare 2004, Tàbara et al 2008, Ripoll-Bosch et al 2012, Saltelli and Giampietro 2017). We performed a participatory integrated sustainability assessment of the implementation of FEW resources on roofs based on a novel combination of participatory processes with different methodologies, such as a Multi- scale Integrated Assessment of Societal and Ecosystem Metabolism (MuSIASEM) (Giampietro et al 2014) and a life cycle assessment (LCA). Our study aims to be applicable to urban mitigation strategies, defining the specific indicators to be considered and the methods for the analysis. To do this, we i) codesign with stakeholders, identify and propose a set of indicators to assess the implementation of different roof mosaic scenarios through a coherent, comprehensive and multi-scale methodology and ii) implement participatory processes in which stakeholders are allowed to value climate change adaptation and mitigation strategies that affect their daily life. 2. Materials & methods The conception of this research is founded on an initial article dedicated to the metabolism of the area under study, the municipality of Badia del Vallès (13,466 inhabitants; density: 14,387 inhabitants km−2), a typical housing estate in the Metropolitan Area of Barcelona (AMB) that faces common environmental, economic and social issues such as energy and water poverty and urban and social degradation (Toboso-Chavero et al 2021). The two methodological components that constitute this study are the participatory processes (steps 1, 2 and 6; section 2.1) and the sustainability assessment (steps 4 and 5; section 2.2). The framework used (figure 1) is based on a combination of quantitative and qualitative methodologies with the aim of proposing a comprehensive and participatory assessment for the deployment of a novel strategy: the roof mosaic. 2.1. Participatory processes stages The participatory processes are split into two stages. Stage 1: Codesign of scenarios and of assessment indicators. The first participatory process was carried out with residents of the municipality who were over 18 years of age. Participants were invited in December 2018. A 2 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al Figure 1. Framework for participatory integrated sustainability assessment. Table 1. Matrix to establish the scores of the different answers related to the concepts retrieved from the participatory process. SCORE 1 2 3 4 5 Frequency of the concepts 1 to 3 4 to 6 7 to 10 11 to 13 more than 13 workshop of fourteen neighbours (29% women, 71% men) was conducted with no preselection of participants based on the World Café methodology (Brown 2005). This methodology is characterized by a relaxed environment of small groups (4/5 people maximum), with a facilitator that gives agency to the participants, and takes notes of all the conversations on the topic proposed. The workshop aimed to scrutinize the concerns and preferences of neighbours related to their municipality, the application of FEW systems on their roofs and the relevant indicators for them. According to the IAP2, this participatory process is at the ‘collaborative’ level, the second highest position within the spectrum of public participation. The design protocol for the participatory process is available in the supporting information. We examined the data based on grounded theory methods (Corbin and Strauss 1990), coded the data, and extracted the key concepts from the answers. Subsequently, we applied content analysis by counting the concept frequencies. They were scored from 1 to 5 depending on the number of responses related to each concept (table 1). Stage 2: Participatory decision-making. This process was carried out in September 2020 and aided in identifying neighbours’ preferences and comparing the most suitable scenarios obtained from the sustainability assessment. We designed six different posters with this information. One poster displayed the current situation in the municipality as retrieved from a consumption pattern survey carried out by the authors (Toboso-Chavero et al 2020), and five posters (see posters in the supporting information) with the five scenarios proposed and with all the indicators (section 2.2). An exhibit of these posters and a short questionnaire were conducted in the 3 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al municipality. This questionnaire could be answered online at https://docs.google.com/forms/d/e/ 1FAIpQLSepoPptehmltBNNHRToShSGGCetksv31ssXcE2ub5AciqIkUQ/viewform or in hard copy. The questionnaire asked for gender, age, and type of stakeholder and then asked for the most suitable scenario for the municipality and also a ranking from the first position to the last position of the five scenarios. The possibility of not using rooftops for anything was also included. The exhibit lasted for twelve days, and residents were able to vote for their choices within this time. After that, all the responses were gathered, analysed, and compared with those retrieved from the sustainability assessment (see the following protocol in the supporting information). According to the IAP2, this participatory process is at the ‘involve’ level, the middle position in the spectrum of public participation. Furthermore, it was performed under COVID-19 circumstances (September 2020), where no more than ten people were allowed to meet in the same place and visits to the exhibition were restricted to those with a prior appointment. 2.2. Integrated sustainability assessment This component includes an array of environmental, social and economic indicators selected in harmony with previous studies (Toboso-Chavero et al 2019, 2021) and the residents’ concerns resulting from the participatory process (section 2.1). Table 2 summarizes the different indicators, including the degree of interest that was assessed, including the same scores as in section 2.1. The indicators used for the sustainability assessment were as follows: 2.2.1. Sustainability indicators These indicators include environmental, social and economic dimensions. Therefore, we included them under the same umbrella and with the same name: sustainability indicators. The MuSIASEM was employed to calculate four different indicators: self-sufficiency and production of vegetables, electricity and water. The increase in green spaces (m2/inhabitant) was chosen as the most commonly used indicator for measuring green infrastructures (Van Herzele and Wiedemann 2003, Taylor et al 2011, Kabisch and Haase 2013). 2.2.2. Environmental indicators The LCA methodology was used for three of the environmental indicators: Global Warming (GW; kg CO2eq m−2/year), Global Warming of the conventional networks for CO2 savings (kg CO2eq m−2/year), and Cumulative Energy Demand (CED; MJ m−2/year) (Hischier et al 2010). These indicators were evaluated in compliance with ISO 14040-44 (ISO 2006) using Simapro 9.0 software with the ReCiPe method at the midpoint level (hierarchical perspective) and the Ecoinvent Database 3.5 (Swiss Centre For Life Cycle Inventories 2018). The functional unit is 1 m2 that supplies different resources, this translates into the supply of electricity (76 kWh m−2 year−1), vegetables—tomatoes, lettuces, green beans and peppers—(10.3 kg m−2 year−1 for open-air farming (OAF)) (Boneta et al 2019) and 14.16 kg m−2 year−1 for rooftop greenhouses (RTGs) (Rufí-Salís et al 2020)), a 1 m2 year−1 green roof (GR) system and 1 m3 year−1 of rainwater harvesting (RWH). The system boundaries include the extraction of raw materials, production, transport and use, and the end-of-life is excluded due to the long life span of the systems, which was assumed to be 30 years. All the inventories of photovoltaic (PV) panels, GR, OAF, RTG, RWH and conventional networks are available in open access (Toboso-Chavero et al 2021). They came from experimental data from the Barcelona region and were adapted to this study. Other derived indicators for the LCA were CO2 payback time (CPBT; years) (Phylipsen and Alsema 1995) and energy payback time (EPBT; years) (Sumper et al 2011). 2.2.3. Social indicators The MuSIASEM methodology was effective for providing different types of social indicators, such as the human activity budget (hours (h)/year) and maintenance investment (h/household/year). Energy and water poverty, i.e., ‘an inability to realise essential capabilities as a direct or indirect result of insufficient access to affordable, reliable and safe energy/water services’ (Day et al 2016) are based on the literature as the most commonly used indicators for this topic (Lawrence et al 2002, The Green/EFA group of the European Parliament 2016). 2.2.4. Economic indicators Different indicators, such as investment and maintenance costs, were obtained from companies that work and currently implement these types of systems. The monetary savings were retrieved from public prices (2019) of electricity, water, and vegetables. The payback period was also selected, as it is a relevant indicator in the field (Watson 2004). 4 Environ. Res. Commun. 3 (2021) 065001 Table 2. List of indicators for assessing the different proposed scenarios. Degree of Indicator Description Unit Calculation Reference interest Sustainability Indicators Self-sufficiency Quantifies the percentage of the self-production on rooftops of the different % (percentage) (TS/TC)*100 MuSIASEM 4 resources Increase in green spaces Considers the total green area (GR, OAF, RTG) in relation to the total m2/inhabitant TGS/Tin Van Herzele and Wiedemann (2003), Taylor et al 1 population (2011), Kabisch and Haase (2013) Production of vegetables Quantifies the quantity of vegetables produced per m2 of rooftop and year kg m−2 year−1 TS/TR MuSIASEM 4 Production of electricity Quantifies the quantity of electricity produced per m2 of rooftop and year kWh m−2 year−1 TS/TR MuSIASEM 5 Production of water Quantifies the quantity of water harvested per m2 of rooftop and year L m−2/year TS/TR MuSIASEM 4 Environmental Indicators å s = 1 GWc n CO2 savings Quantifies the annual avoided GHG emissions (Global Warming impact kg CO2 eq m−2/year LCA- Recipe method (H), Goedkoop et al (2013) 4 category) related to FEW conventional networks per m2 of rooftops if the decentralised systems are implemented 5 å s = 1 GWp n Global Warming Quantifies the total GHG emissions of the construction phase of FEW sys- kg CO2 eq m−2/year LCA- Recipe method (H), Goedkoop et al (2013) 3 tems (OAF, RTG, GR, PV panels and RWH) CO2 payback time (CPBT) It is the time period required for a system to avoid the production of the same years GWp/GWc LCA- Phylipsen and Alsema (1995) 1 amount of CO2 generated to produce the system itself å s = 1 CED n Cumulative Energy Represents the direct and indirect energy use throughout the life cycle of the MJ m−2 year−1 LCA- Hischier et al (2010) 1 Demand (CED) FEW systems (OAF, RTG, GR, PV panels and RWH) Energy payback Considers the time need to compensate the energy produced by the construc- years CED/Eg LCA- Sumper et al (2011) 1 time (EPBT) tion of the FEW systems Social Indicators Energy poverty coverage Quantifies de number of households coverage of electricity from decen- (%; number of households) TS/Th The Green/EFA group of the European Parlia- 3 tralised systems ment (2016) Water poverty coverage Quantifies de number of households coverage of water from decentralised (%; number of households) TS/Th Lawrence et al (2002) 3 systems Human activity bud- It is the human time of a given population dedicated to each system (FEW) total hours/year — MuSIASEM- Giampietro et al (2012) // Project 4 get (THB) data & Distribution companies Maintenance investment Hours of dedication for each system (OAF, RTG, GR, PV panels and RWH) hour/household/year THB/Th MuSIASEM // Project data & Distribution 4 per household and year companies S Toboso-Chavero et al Economic Indicators Monetary savings (MS) Quantifies the amount of annual money savings for using decentralised sys- €/household/year — Public prices 5 tems per household and year Investment (TI) The money invest to implement the decentralised systems (OAF, RTG, GR, € m−2 — Distribution companies 5 PV panels and RWH) per m2 Environ. Res. Commun. 3 (2021) 065001 Table 2. (Continued.) Degree of 6 Indicator Description Unit Calculation Reference interest Maintenance cost Considers the annual maintenance cost of the implementation of decen- € m−2/year — Distribution companies 5 tralised systems per m2 and year Payback period It is the time, expressed in years, required to generate sufficient savings to years TI/MS Watson (2004) 1 recover the initial capital outlay of the project TS=Total annual supply; TC=Total annual consumption; TR=Total m2 of rooftops; TGS=total green spaces; Tin=Total inhabitants; GWc=Global Warming of conventional networks; GWp=Global Warming production phase; CED=Cumulative Energy Demand ; Eg=Energy generated; Th=Total households; THB=Total human budget; TI=Total Investment; TMS=Total monetary savings. S Toboso-Chavero et al Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al Table 3. Outcomes of the first participatory process. Main social perceptions of the residents regarding their municipality and the use of roofs. Score=1 to 5. Conforming to these indicators, the results present the most viable scenarios considering the objective indicators and residents’ concerns and preferences. The quantitative indicators were later compared with the results of the participatory decision-making process of the residents’ choices. 3. Results 3.1. Codesign of scenarios and assessment indicators A set of scenarios and indicators were proposed based on the preferences of participants at our workshop. The concerns of the municipality’s residents (table 3) are mainly related to aging, many senior citizens living alone, lack of social cohesion and lack of economic resources. They are also worried about the lack of residents’ commitment and limited political involvement in the issues of the municipality. Related to the implementation of these new systems on their roofs, i.e., food and energy production and rainwater harvesting, the neighbours predominantly selected energy production, particularly electricity, due to the high price of this resource, which ranges between 50–80 €/family/month, and then water and vegetables, despite spending an average of 60–80 €/family/month (Toboso-Chavero et al 2020). On the one hand, the residents perceive a significant investment as difficult to afford, and on the other hand, they are concerned about the lack of involvement among their neighbours and want to know who will take care of these new systems placed in shared spaces. The participants also see many opportunities in the deployment of these systems, such as money and resource savings and self-sufficiency, empowering them to organise and assure these resources on their own. The participatory process was fundamental for the proposal of scenarios because many scenarios could be implemented, yet only a limited number are in line with the residents’ priorities. Accordingly, five different scenarios were presented (scenario 1 (S1; 100% photovoltaic (PV) panels and rainwater harvesting (RWH), i.e., all the rooftops become equipped with PV panels and set up for RWH), scenario 2 (S2; 50% PV+50% green roofs (GR), half of the rooftops become equipped with PV and the other half with GR, and RWH is conducted on all the rooftops), scenario 3 (S3; 50% PV+50% open-air farming (OAF) and RWH), scenario 4 (S4; 50% PV+50% rooftop greenhouses (RTG) and RWH) and scenario 5 (S5; 25% PV+25% GR+25% OAF+25% RTG+RWH)). Regarding the indicators, the residents were mainly concerned about the initial costs and maintenance costs, as well as monetary savings. They were also interested in the environmental aspects of the options but in a more generic way and in the production of resources, in principle as a way to save money but also as a means to improve the environment in their municipality. 3.2. Characterising environmental, social and economic dimensions to support decision-making processes regarding scenario sustainability We evaluated the different scenarios through environmental, social and economic dimensions (figure 2). According to these analyses, scenario 1 obtained the most favourable indicators, attaining the majority of its highest values in the social indicators and the others in electricity self-sufficiency (35%), monetary savings (742 7 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al Figure 2. Sustainability assessment of the five proposed scenarios. S1: scenario 1 (PV+RWH); S2: scenario 2 (PV+GR+RWH); S3: scenario 3 (PV+OAF+RWH); S4: scenario 4 (PV+RTG+RWH); S5: scenario 5 (PV+GR+OAF+RTG+RWH); h: hour; hh: household; inh: inhabitant; CPBT: CO2 payback time; CED: cumulative energy demand; EPBT: energy payback time. Conventional networks are available in open access (Toboso-Chavero et al 2021). €/household/year) and CO2 savings (47 kg CO2eq m−2/year). Nevertheless, it also has the most unfavourable indicators because its performance is mainly based on one resource, i.e., electricity. Scenario 4 is the scenario with the second-most positive indicators, particularly in vegetable self-sufficiency (56%; 14.16 kg m−2 year−1) and having enough rainwater to irrigate all crops. However, its performance is worse in the social and economic categories than that of scenario 1. Scenarios 2, 3 and 5 have fewer beneficial indicators, especially scenario 2, which obtained a substantial number of indicators with poor performance, such as the EPBT (6.7 years) and CPBT (2.5 years). If we compare the different scenarios according to each indicator’s average, we can assert that scenarios 3 and 4 perform considerably better than the other scenarios. These two scenarios provide vegetables—through open- air farming and greenhouses—on half of the roofs, electricity on the other half and enough water to irrigate almost all crops. However, in principle, in the first participatory process, residents indicated that they mainly preferred electricity (section 3.1), and scenario 1 offered more electricity than either of these two scenarios (S3 & S4). Nevertheless, scenario 1 has the second highest investment cost and does not provide vegetables. Conversely, scenario 2 has the fewest indicators that are above each indicator’s average. It is only the best in water self-sufficiency because less irrigation is required for extensive green roofs of sedum and in the initial investment of the systems because fewer materials are necessary. Likewise, scenario 5 has the second fewest favourable indicators. This is because in this scenario, all the systems (PV, GR, OAF, RTG and RWH) are deployed on the municipality’s roofs, resulting in lower values for most of the indicators. However, in the environmental categories, this scenario performs excellently, particularly in the increase in green spaces (3.7 m2/inhabitant), decrease in Global Warming (35 kg CO2eq m−2), short CPBT (1.4 years) and low Cumulative Energy Demand (582 MJ m−2), which implies that this option is the least environmentally demanding. These indicators support the decision-making process used to select future scenarios for this municipality. The three pillars of sustainability are represented here: environmental, social and economic dimensions. Depending on the needs of each area, the importance of each indicator will vary. This is the reason why a participatory process is vital to the acceptance of this strategy and the selection of the most suitable option. 3.3. Characterisation of residents’ preferences Given the sustainability assessment of the scenarios, the different stakeholders had the opportunity to participate in the selection of the most practicable options. They received information on the different indicators via a poster for each scenario and voted on the most suitable alternative for their municipality in situ or online. The exhibit was opened under COVID-19 restrictions. Therefore, it was complicated to gather the opinions of the residents over 65 years old since these residents are not familiar with online questionnaires. Consequently, only 8% of the total respondents were older than 65 years. The most representative age groups were 19 to 44 (58%) and 45 to 65 (32%). Similarly, women are under-represented relative to men, with only 35% of the total participants being female (See the table in figure 3). The outcomes display a clear preference for scenario 1; 6 out of 10 residents chose to use their rooftops for producing electricity and collecting rainwater for flushing toilets. This ratio coincides with the first participatory process, where residents agreed as a first option to implement PV panels on their roofs. The second most 8 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al Figure 3. Outcomes of the exhibit. The half-pie charts are the preferred scenarios of the residents. The table represents the type of resident who voted, split by gender, age group and type of stakeholder. The graphs in the bottom section illustrate the share of residents from each building typology (same colours as in figure 2) that voted for each scenario as first to fifth option. Type of stakeholder: percentage is higher than 100% because some participants selected two characteristics, e.g., resident and expert. Conventional networks are available in open access (Toboso-Chavero et al 2021). Figure 4. Outcomes classified by gender, age group and stakeholder. S1: scenario 1 (PV+RWH); S2: scenario 2 (PV+GR+RWH); S3: scenario 3 (PV+OAF+RWH); S4: scenario 4 (PV+RTG+RWH); S5: scenario 5 (PV+GR+OAF+RTG+RWH). supported option was scenario 2, but only by 17% of the residents. Furthermore, when a ranking was requested, this scenario also appeared in the second position; nevertheless, only 38% preferred this option, followed by scenarios 3 (23%) and 4 (20%). The third most-preferred alternative was a tie between scenarios 3 and 5. However, in the ranking, the third most-preferred scenario was scenario 3. The least preferred option was scenario 4, with barely 3% of the respondents selecting this option; however, in the ranking, the least-preferred option was scenario 5 (53%). Either way, scenarios 4 and 5 are the alternatives with the least support among residents. Considering the scenarios preferred by those with different characteristics, differences by gender can be seen, where women had a more diverse opinion, voting primarily for scenarios 1 and 2 with no votes for scenario 4 (see figure 4, left-hand bar chart). For men, the best option was certainly scenario 1 (76%). In regard to age groups, the residents aged 19–44 years, the best represented group, mainly preferred scenario 1; 7 out of 10 would like to implement the production of electricity on their roofs, which is in accordance with the general results. On the other hand, the 45–65 and over 65 years old groups preferred the same option, scenario 1, but to a lesser extent. Furthermore, combining age group and gender indicates that scenario 1 was mainly selected by men, in particular men aged 19–44; in contrast, scenario 2 was mainly chosen by women (70%) and especially women aged 45–65 and more than 65 years old, accounting for 50% of the votes for this scenario. The stakeholders participating in this process were mostly residents, and accordingly, they preferred scenario 1. Experts and experts+residents (6 respondents) selected only scenario 1 and public institutions and experts+public institutions (5 respondents) opted for scenarios 3, 4 and 5, which each included the production of vegetables. 9 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al Table 4. Ranking from the sustainability assessment compared to that from the participatory voting. Position 1 2 3 4 5 Sustainability Assessment Scenario 1 Scenario 4 Scenario 3 Scenario 5 Scenario 2 Participatory Voting Scenario 1 Scenario 2 Scenario 3 Scenario 5 Scenario 4 4. Discussion 4.1. Comparison between residents’ preferences and the sustainability assessment outcomes We identified some discrepancies between the residents’ preferences and the outcomes of the sustainability assessment. Such discrepancies are mostly present for scenarios 2 and 4. Scenario 1 was selected as the first choice of the residents and was also the alternative with the most favourable indicators in the sustainability assessment. Scenario 4 was the second option in the sustainability assessment, but it was ranked last by the residents because the construction of a greenhouse on their buildings was still difficult for them to envision. The fact that the upfront investment is high together with the lack of examples of rooftop greenhouses in Spain were some of the reasons presented. In contrast, scenario 2 received the second most votes from residents but performed the worst in the sustainability assessment. The rest of the rankings are listed in table 4 below. Considering the outcomes from the first and second participatory processes, the residents showed more interest in reducing their electricity expenses by selecting scenarios 1 and 2 than in reducing their food expenses. They did not opt for the scenarios providing vegetables (scenarios 3, 4 and 5), although they spend an average of 77 €/family on vegetables versus 63 €/family per month on their average energy bill (Toboso-Chavero et al 2021). This can be explained by two factors. First, the food bill is split into different purchases throughout the month as opposed to a single bill in electricity. Second, residents did not perceive food production as an activity impacting global networks, and the possible lack of food supply, i.e., food insecurity, has not been identified as an issue in the municipality. Hence, if the municipality aimed to foster urban rooftop agriculture, it would need to apply policies targeting the awareness of family food expenses and the related impacts of the conventional food supply. These policies would have to mostly target men because men showed more reluctance to implement any option that is not PV panels. The application of participatory processes with the sustainability assessment was crucial to identify the concerns of the residents regarding energy expenses in this housing estate, i.e., energy insecurity, and the lack of concern about food expenses or the environmental impacts of global food supply chains, and to identify how residents have a false sense of food security, which is also taken for granted in other Western countries (Borch and Kjærnes 2016). Residents undervalued the possibility of access to fresh vegetables or the necessity to provide for themselves. Neighbours also did not consider roofs as a new place for vegetable gardens to promote social cohesion, which they complained about in the first participatory process. In contrast, they envisioned their municipality mainly as being suitable to host a myriad of photovoltaic panels for alleviating their electricity needs and with minimum dedication to management in their buildings. In concordance with the findings of previous works on housing estates (Baldwin Hess et al 2018), the main concerns of the residents in this municipality are related to social and economic limitations, to the neglect of environmental issues, which are secondary due to the basic needs residents must satisfy. 4.2. Applicability, limitations and policy suggestions In this study, we propose a method to bring science, policy and society closer together to enhance decision- making related to urban planning strategies. To that end, we added a participatory component to the integration of LCA and social metabolism assessments. Our results show how decision-informing analyses are better suited to their goal if, for the ranking of options, they consider (i) the integration of environmental, social and economic indicators and (ii) the values of stakeholders. Many studies strive to quantify environmental impacts and the relations among water, food and energy flows without a proper consideration of the role that their associated social and economic dimensions play in the acceptance of and in confidence in new urban strategies (Newell et al 2019). By integrating environmental, social and economic parameters, the method presented captures the local context of the area under study, providing relevant indicators to best customise rooftop development to meet the municipality’s needs. In the case of housing estates that share similar environmental, social and economic issues, the similarity in the urban design, the repetition of the same type of buildings, flat roofs, etc, are advantages in replicating the rooftop mosaic. Nevertheless, the complexity of the trade-offs among the environmental, social and economic parameters challenges one-sided decision-making processes. By incorporating the stakeholder’s values in the decision process, complexity is embraced and managed. To provide proper guidance, this participation should go beyond 10 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al mere consultation and reach at least the level of collaboration3 as described by the IAP2 Federation (International Association of Public Participation 2020). Collaboration ensures selection of the scenarios that are better suited to the goal of the study, increasing the probability of a successful implementation. A number of examples of urban development projects that failed due to the opposition of citizens can be found in the literature; see the case of the superblock programme’s pilot project in Barcelona, a large-scale intervention to address climate change challenges (Zografos et al 2020), or the failed wind farm projects in some communities (Bell et al 2005, Hindmarsh 2010). This case study was based on a housing estate owned by the local government and built in 1976, where few renovations have been made to the building stock. The façades and roofs of this housing estate need to be refurbished. Furthermore, this situation is similar to that in many housing estates in Europe (Blos 1999, Scalon and Whitehead 2008) and in the Barcelona region, namely, the Montbau and Ciutat Meridiana neighbourhoods and the Bellvitge municipality (Blos 1999, Monclús et al 2017). Consequently, the most plausible path for their renovation would be a public investment to upgrade these areas due to the economic and social issues faced by the residents, who are not able to bear these costs. This is an opportunity for public institutions to manage not only the rehabilitation of these areas but also to provide basic resources (FEW) produced on rooftops in order to ameliorate the energy and water poverty and food insecurity that some households have to cope with. Examples of new public initiatives in Barcelona for boosting rooftop use are the green roof competition4 or the installation of PV or solar thermal panels on roofs5, for which the city council subsidizes 75% and 50% of the initial cost. Another type of initiative is the proliferation of energy companies that commercialize only renewable energies, which guide citizens and help them install PV panels on their roofs through shared investments (energy cooperatives). Nevertheless, there are still some limitations to overcome in the use of roofs as productive urban spaces, as pointed out by Zambrano-Prado et al (2021) and as shown in the participatory processes we carried out. The main barriers are related to social aspects such as a lack of agreement or social cohesion among residents and maintenance responsibility, and to economic aspects such as the initial and maintenance costs. By applying the proposed framework, policymakers can foster agreements and social cohesion among stakeholders by working together to find the best future scenario for the municipality. Having environmental, social and economic indicators for these rooftop mosaic scenarios provides a framework for selecting the best alternative from all plausible perspectives and readapting the current urban regulations and policies for easy implementation of FEW production on roofs. Some examples of these policies can be found in the city of Paris with the reform of the local urban plan (PLU) (Mairie de Paris 2016), which among other things, obliges the vegetalisation of roofs larger than 200 m2 in new construction, does not consider rooftop greenhouses to be a new story to the building and promotes new green spaces, of which 30 hectares must be for urban agriculture. Another example is Barcelona, which has an urban agriculture strategy for the city that promotes roofs as key spaces for increasing green spaces and vegetable production in the city in order to attain 1 m2 more per person of green infrastructure by 2030 (Ajuntament de Barcelona 2019). The city council also established a strategy for promoting solar energy generation that aims to increase self-consumption, self-production and renewable and local generation and is focused on public and private roofs with public or private investments (Ajuntament de Barcelona 2017). 5. Conclusions The participatory integrated sustainability assessment presented here aims to help decision-makers build an integrated assessment that includes an array of environmental, social and economic indicators and methodologies that engage stakeholders in every stage of the project. The first participatory process proposed five future roof mosaic scenarios and provided a guide for the selection of assessment indicators, such as the production of resources and investment and maintenance costs. The sustainability assessment appraised the roof mosaic scenarios environmentally, socially and economically, indicating that scenarios 1 (the implementation of PV panels and rainwater harvesting) and 4 (deploying greenhouses, PV panels and rainwater harvesting) were the best options and scenario 2 (PV panels, green roofs and rainwater harvesting) was the least advisable. Subsequently, carrying out a second participatory process with the residents in which the five scenarios with all the indicators’ outcomes were presented, we identified some discrepancies between the sustainability assessment and the residents’ preferences, which agreed with scenario 1 (65%), voted for mainly by men (75%), as the best option, but which did not agree with the rankings of the rest of 3 ‘To collaborate’ is defined as ‘to partner with the public in each aspect of a decision.’ 4 https://ajuntament.barcelona.cat/ecologiaurbana/en/green-roof-competition 5 https://energia.barcelona/ca/ajuts-i-subvencions-convocatoria 11 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al the options. Scenario 2 was the second-most preferred option among the residents (17%) and was mainly selected by women (70%) but was in the last position in the sustainability assessment. Conversely, scenario 4 was the second-best option in the sustainability assessment but the last choice among the residents (3%). The outcomes and methods used serve as a basis for prioritising and optimising future sustainable scenarios for cities in the production of their own resources. These methods were specifically applied in a housing estate in the Barcelona region but could be useful in housing estates in other European countries or in other types of urban settings. Future research could study the implementation and follow-up of a pilot project on housing estates’ rooftops to evaluate the technical and operational limitations as well as the benefits. Currently, different productive farming and productive energy rooftops have been implemented in the city of Barcelona (Ajuntament de Barcelona 2018, Ajuntament de Barcelona 2020), but none in this type of urban area, i.e., in housing estates. Therefore, we recommend that researchers, institutions and the general public continue working together to (a) foster urban strategies, such as the roof mosaic, where it is most needed, (b) design the most feasible sustainability scenarios through comprehensive assessments, (c) propose policies to address the lack of knowledge of the environmental impacts of conventional supply networks and readapt current urban planning regulations and (d) inform and educate citizens by implementing policies meant to promote local resource production in municipalities. Acknowledgments We would like to thank the Associació Veinal de Badia del Valles and the city council of Badia del Vallès, in particular to Joaquin Nogués and Daniel Serrano, and the Sorea company for their availability and collaboration, and Carlos Toboso from the University of Seville for his guidance and support in all architecture issues. Data availability statement The data that support the findings of this study are openly available at the following URL/DOI: http://doi.org/ 10.5565/ddd.uab.cat/237969. Conflict of interest statement The authors declare no conflict of interest. Ethical statement The protocol for the participatory processes was approved by the Ethics Committee on Animal and Human Experimentation of the Autonomous University of Barcelona (https://www.uab.cat/web/human-research/ presentation-1345735629170.html); Reference number: CEEAH 4520. Funding information The research leading to this publication has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 862663 (FoodE). The publication reflects the author’s views. The Research Executive Agency (REA) is not liable for any use that may be made of the information contained therein. This research has also received financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) project CTM2016-75772-C3-1-3-R (AEI/FEDER, UE) and «María de Maeztu» Units of Excellence (CEX2019-000940-M)); the Spanish Ministry of Education, Culture and Sports grant FPU16/03238; the European Commission’s ERC Consolidator grant 818002-URBAG and Greenhouses to Reduce CO2 on Roofs (GROOF) project (UE. Interreg NWE 474, 2017-2021). ORCID iDs Susana Toboso-Chavero https://orcid.org/0000-0001-8475-5184 Cristina Madrid-López https://orcid.org/0000-0002-4969-028X Xavier Gabarrell Durany https://orcid.org/0000-0003-1730-4337 Gara Villalba https://orcid.org/0000-0001-6392-0902 12 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al References Ajuntament de Barcelona 2018 Green Roofs in Barcelona (https://ajuntament.barcelona.cat/ecologiaurbana/en/green-roof-competition Ajuntament de Barcelona 2020 Map of photovoltaic energy generation in Barcelona (https://energia.barcelona/ca/mapa-de-generacio- denergia-en-edificis-municipals) Ajuntament de Barcelona 2017 Program to promote the generation of solar energy in Barcelona. The increase in renewable and local generation (https://bcnroc.ajuntament.barcelona.cat/jspui/handle/11703/115675) Ajuntament de Barcelona 2019 The urban agriculture strategy in the city of Barcelona (https://bcnroc.ajuntament.barcelona.cat/jspui/ handle/11703/116590) Baldwin Hess D, Tammaru T and van Ham M 2018 Housing Estates in Europe. Poverty, Ethnic Segregation and Policy Challenges (http:// springer.com/series/14773) Bazán J, Rieradevall J, Gabarrell X and Vázquez-Rowe I 2018 Low-carbon electricity production through the implementation of photovoltaic panels in rooftops in urban environments: a case study for three cities in Peru Sci. Total Environ. 622–623 1448–62 Bell D, Gray T and Haggett C 2005 The ‘social gap’ in wind farm siting decisions: Explanations and policy responses Env. Polit. 14 460–77 Blos D 1999 The social housing estates. Perspectives towards their recovery in Spain, France and Brazil PhD Thesis. Universitat Politècnica de Catalunya (http://hdl.handle.net/2117/93441) Boneta A, Rufí-Salís M, Ercilla-Montserrat M, Gabarrell X and Rieradevall J 2019 Agronomic and Environmental Assessment of a Polyculture Rooftop Soilless Urban Home Garden in a Mediterranean City Front. Plant Sci. 10 341 Borch A and Kjærnes U 2016 Food security and food insecurity in Europe: an analysis of the academic discourse (1975–2013) Appetite 103 137–47 Brown J 2005 The World Café: Shaping Our Futures Through Conversations That Matter (San Francisco: Berrett-Koehler Publishers) (www. amazon.com/World-Cafe- Resource-Hosting-Conversations/dp/097247160X) Cerón-Palma I, Sanyé-Mengual E, Oliver-Solà J, Montero J I and Rieradevall J 2012 Barriers and opportunities regarding the implementation of Rooftop Eco.Greenhouses (RTEG) in Mediterranean Cities of Europe J. Urban Technol. 19 87–103 Corbin J and Strauss A 1990 Grounded theory research: procedures, canons, and evaluative criteria Qual. Sociol. 13 3–21 Cucchiella F and Dadamo I 2012 Estimation of the energetic and environmental impacts of a roof-mounted building-integrated photovoltaic systems Renew. Sustain. Energy Rev. 16 5245–59 Day R, Walker G and Simcock N 2016 Conceptualising energy use and energy poverty using a capabilities framework Energy Policy 93 255–64 Ercilla-Montserrat M, Sanjuan-Delmás D, Sanyé-Mengual E, Calvet-Mir L, Banderas K, Rieradevall J, Xavier G, Gabarrell X and Cat X G 2019 Analysis of the consumer’s perception of urban food products from a soilless system in rooftop greenhouses: a case study from the Mediterranean area of Barcelona (Spain) Agric. Human Values 36 375–93 European Commission 2014 Green Paper on Citizen Science (https://digital-strategy.ec.europa.eu/en/library/green-paper-citizen-science- europe-towards-society-empowered-citizens-and-enhanced-research) FAO 2017 The State of Food and Agriculture vol 19 (Rome) (www.fao.org/3/I7658e/I7658e.pdf) Finkbeiner M, Schau E M, Lehmann A and Traverso M 2010 Towards life cycle sustainability assessment Sustainability 2 3309–22 Garcia D J and You F 2016 The water-energy-food nexus and process systems engineering: a new focus Comput. Chem. Eng. 91 49–67 Giampietro M, Aspinall R J, Ramos-Martin J and Bukkens S G F 2014 Resource Accounting for Sustainability. The Nexus Between Energy, Food, Water and Land use (New York: Routledge) (https://www.taylorfrancis.com/chapters/edit/10.4324/9781315866895-27/resource- accounting-sustainability-assessment-mario-giampietro-richard-aspinall-jesus-ramos-martin) Goedkoop M, Heijungs R, Huijbregts M, De Schryves A, Strujis J and van Zelm R 2013 A Life Cycle Impact Assessment Method Which Comprises Harmonised Category Indicators at the Midpoint and the Endpoint Level First Ed. (version 1.08) Report I: Characterisation Hindmarsh R 2010 Wind farms and community engagement in Australia: a critical analysis for policy learning East Asian Sci. Technol. Soc. An Int. J. 4 541–63 Hischier R et al 2010 Implementation of Life Cycle Impact Assessment Methods. ecoinvent report No. 3, v2.2. (Dübendorf, CH.) (www. ecoinvent.org/files/201007_hischier_weidema_implementation_of_lcia_methods.pdf) IEA 2015 Energy Technology Perspectives (https://iea.blob.core.windows.net/assets/37fe1db9-5943-4288-82bf-13a0a0d74568/Energy_ Technology_Perspectives_2016.pdf) International Association of Public Participation 2020 The P2 pillars 2 (https://iap2.org/mpage/Home) International Organization for Standardization 2006 Environmental management – life cycle assessment – principles and framework (ISO Standard No. 14040:2006) (www.iso.org/obp/ui#iso:std:iso:14040:ed-2:v1:en) Kabisch N and Haase D 2013 Green spaces of European cities revisited for 1990–2006 Landsc. Urban Plan. 110 113–22 Kloepffer W 2008 Life cycle sustainability assessment of products (with Comments by Helias A. Udo de Haes, p 95) Int. J. Life Cycle Assess. 13 89–95 Kühnen M and Hahn R 2019 From SLCA to positive sustainability performance measurement: a Two-Tier Delphi study J. Ind. Ecol. 23 615–34 Lamnatou C and Chemisana D 2014 Photovoltaic-green roofs: a life cycle assessment approach with emphasis on warm months of Mediterranean climate J. Clean. Prod. 72 57–75 Lawrence P, Meigh J and Sullivan C 2002 The water poverty index: an international comparison (Keele, Staffordshire, UK: Department of Economics, Keele University.) Mairie de Paris 2016 Paris Land Use Plan (Paris) (https://cdn.paris.fr/paris/2020/02/26/16107d9c38a049046444a7b6301df1aa.ai) Monclús J, Díez Medina C and García-Pérez S 2017 Housing estates as urban legacy: urban forms and open spaces (https://idus.us.es/ xmlui/handle/11441/57566) Newell J P, Goldstein B and Foster A 2019 A 40-year review of food–energy–water nexus literature and its application to the urban scale Environ. Res. Lett. 7 073003 Newell J P and Ramaswami A 2020 Urban food–energy–water systems: past, current, and future research trajectories Environ. Res. Lett. 15 050201 O’Faircheallaigh C 2010 Public participation and environmental impact assessment: Purposes, implications, and lessons for public policy making Environ. Impact Assess. Rev. 30 19–27 Pahl-Wostl C 2002 Towards sustainability in the water sector - The importance of human actors and processes of social learning Aquat. Sci. 64 394–411 (Birkhauser Verlag AG) Pahl-Wostl C and Hare M 2004 Processes of social learning in integrated resources management J. Community Appl. Soc. Psychol. 14 193–206 13 Environ. Res. Commun. 3 (2021) 065001 S Toboso-Chavero et al Phylipsen G J M and Alsema E A 1995 Environmental life-cycle assessment of multicrystalline silicon solar cell modules Analysis 65 (http:// citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.126.292&rep=rep1&type=pdf) Ripoll-Bosch R, Díez-Unquera B, Ruiz R, Villalba D, Molina E, Joy M, Olaizola A and Bernués A 2012 An integrated sustainability assessment of mediterranean sheep farms with different degrees of intensification Agric. Syst. 105 46–56 Rosenzweig C, Solecki W, Hammer S A and Mehrotra S 2010 Cities lead the way in climate-change action Nature 467 909–11 Rufí-Salís M, Petit-Boix A, Gara Villalba, Ercilla-Montserrat M, Sanjuan-Delmás D, Parada F, Arcas V, Muñoz-Liesa J and Gabarrell X 2020 Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture Int. J. Life Cycle Assess. 25 564–76 Saltelli A and Giampietro M 2017 What is wrong with evidence based policy, and how can it be improved? Futures 91 62–71 Salvador D S, Toboso-Chavero S, Nadal A, Gabarrell X, Rieradevall J and da Silva R S 2019 Potential of technology parks to implement Roof Mosaic in Brazil J. Clean. Prod. 235 166–77 Sanjuan-Delmás D, Llorach-Massana P, Nadal A, Ercilla-Montserrat M, Muñoz P, Montero J I, Josa A, Gabarrell X and Rieradevall J 2018 Environmental assessment of an integrated rooftop greenhouse for food production in cities J. Clean. Prod. 177 326–37 Sanyé-Mengual E, Anguelovski I, Oliver-Solà J, Montero J I and Rieradevall J 2016 Resolving differing stakeholder perceptions of urban rooftop farming in Mediterranean cities: promoting food production as a driver for innovative forms of urban agriculture Agric. Human Values 33 101–20 Scalon K and Whitehead C 2008 Social Housing in Europe II: a review of policies and outcomes LSE London 307 Specht K, Siebert R and Thomaier S 2016 Perception and acceptance of agricultural production in and on urban buildings (ZFarming): a qualitative study from Berlin, Germany Agric. Human Values 33 753–69 Strasser B J, Baudry J, Mahr D, Sanchez G and Tancoigne E 2019 ‘Citizen science’? Rethinking science and public participation Sci. Technol. Stud. 32 52–76 Sumper A, Robledo-García M, Villafáfila-Robles R, Bergas-Jané J and Andrés-Peiró J 2011 Life-cycle assessment of a photovoltaic system in Catalonia (Spain) Renew. Sustain. Energy Rev. 15 3888–96 Swiss Centre For Life Cycle Inventories 2018 Ecoinvent Database 3.5 3.5 (http://ecoinvent.org/database/) Tàbara D J, Roca E, Madrid C, Valkering P, Wallman P and Weaver P M 2008 Integrated sustainability assessment of water systems: lessons from the Ebro River Basin Int. J. Innov. Sustain. Dev. 3 48–69 Taylor B T, Fernando P, Bauman A E, Williamson A, Craig J C and Redman S 2011 Measuring the quality of public open space using google earth Am. J. Prev. Med. 40 105–12 The Green/EFA group of the European Parliament 2016 Energy Poverty Handbook (Brussels: European Union) (http://bpie.eu/wp- content/uploads/2016/11/energypovertyhandbook-online.pdf ) Toboso-Chavero S, Nadal A, Petit-Boix A, Pons O, Villalba G, Gabarrell X, Josa A and Rieradevall J 2019 Towards productive cities: environmental assessment of the food-energy-water nexus of the Urban Roof Mosaic J. Ind. Ecol. 23 767–80 Toboso-Chavero S, Villalba G, Gabarrell Durany X and Madrid-López C 2021 More than the sum of the parts. System analysis of the usability of roofs in housing estates J. Ind. Ecol. (https://doi.org/10.1111/jiec.13114) Toboso-Chavero S, Villalba G, Gabarrell X and Madrid-López C 2020 Consumption patterns in a housing estate: the municipality of Badia del Vallès (https://doi.org/10.5565/ddd.uab.cat/226152) Toboso-Chavero S, Villalba G, Gabarrell Durany X and Madrid-López C 2021 Inventories and raw data for the research: ‘Incorporating user preferences in rooftop food-energy-water production through integrated sustainability assessment’ United Nations 2020 Sustainable Development Goals (https://un.org/sustainabledevelopment/cities/) Van Herzele A and Wiedemann T 2003 A monitoring tool for the provision of accessible and attractive urban green spaces Landsc. Urban Plan. 63 109–26 Watson J 2004 Co-provision in sustainable energy systems: the case of micro-generation Energy Policy 32 1981–90 Zamagni A 2012 Life cycle sustainability assessment Int. J. Life Cycle Assess. 17 373–6 Zambrano-Prado P, Pons-Gumí D, Toboso-Chavero S, Parada F, Josa A P, Gabarrell Durany X and Rieradevall J 2021 Perceptions on barriers and opportunities for integrating urban agri-green roofs: a European Mediterranean compact city case Cities 14 103196 Zografos C, Klause K A, Connolly J J T and Anguelovski I 2020 The everyday politics of urban transformational adaptation: struggles for authority and the Barcelona superblock project Cities 99 102613 14