Urban horticulture in retail parks: Environmental assessment of the potential implementation of rooftop greenhouses in European and South American cities

This paper performs a multi-national assessment to provide a more comprehensive vision of the potential implementation of Rooftop Greenhouses in retail parks from a theoretical perspective. A geographic information system – life cycle assessment method is used to quantify both the potential and the expected benefits of implementing rooftop greenhouses. We evaluate eight case studies in Europe and South America, paying attention to geographical constrasts (e.g., climate). We also focus on comparing the differences between isolated rooftop greenhouses and integrated rooftop greenhouses by evaluating the implications of a symbiotic metabolism. Results showed that retail parks have a large potential for the implementation of rooftop greenhouses in the short-term (53–98% of the rooftops are technically and economically feasible), being architecture one of the main constraints (i.e., roof material limited the potential to 11% for the Colombian case). Retail parks performed better than industrial parks as urban locations for such projects. The employment of isolated rooftop greenhouses in these areas obtained large values of production (31–234 tonnes of tomato per ha), CO2savings (16–112 tonnes of CO2eq per ha) and food self-supply (380–21,500 people per ha; 3.5–60% of local tomato demand). When considering an industrial symbiosis approach, integrated rooftop greenhouses (with exchange of energy and CO2) could boost food production and self-supply values (up to 1.8 times) as well as the environmental benefits from local production (up to 2.5 times higher). Integrating the water flow from rainwater harvesting on the building into the crop production would ensure crop's water self-sufficiency, apart from one case (69% of self-sufficiency).