Guidelines to optimize covering and structural materials in rooftop-integrated greenhouses: an environmental assessment

It is widely accepted that urban agriculture provides multiple benefits to society. Rooftop greenhouses are a form of urban agriculture that take advantage of urban resources (urban land, building materials, sunlight spaces) and waste flows (energy, nutrients) to provide food and ecosystem services to cities. However, the integration of urban greenhouses within buildings is a complex issue that must be addressed in-depth. Compared to the well-known conventional greenhouses, the urban environment display different constrains requiring to be assessed in order to later optimize greenhouse building materials. The aim of our study was to environmentally assess rooftop greenhouses and propose improving scenarios. Life cycle assessment was used to detect environmental hotspots and to evaluate different impact categories of an iRTG case study in the Barcelona area. Results showed that the greenhouse environment and ventilation design directly determine greenhouse structures and environmental impacts. Optimized strategies showed a potential reduction of up to 35% of the amount of structural steel used, while less improvement potential existed for covering materials (5%). Compared to conventional greenhouses, 1.6 times more steel and up to 8 times more energy were required to build the urban greenhouse in this study. The assessment revealed that these differences can be reduced by optimizing greenhouse structures to avoid a shift of material flows and environmental impacts from building urban greenhouses compared to conventional greenhouses. In turn, the assessment presented here provides guidelines on how to design and plan urban greenhouse constructions in future assessments. That will facilitate the incorporation of urban agriculture in cities based on consistent environmental assessments, ultimately contributing to the low-carbon future development of cities.
The authors are grateful to the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement of Generalitat de Catalunya for awarding a research scholarship (FI-DGR 2021) to Joan Muñoz-Liesa. The authors also acknowledge financial support from the Secretaria d’Universitats i Recerca del Departament de Recerca i Universitats of the Generalitat de Catalunya for the grant awarded under AGAU 2020 PANDE 00021 and the Spanish Ministry of Science, Innovation and Universities through the “Marı́a de Maeztu” program for Units of Excellence in R&D [CEX2019–000940-M].
Peer Reviewed
Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura
Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles
Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables
Postprint (author's final draft)