S08 - Session O4 - Prospecting the implications of urban symbiosis for more circular urban-vertical farming systems

Authors: Michael Martin *

Vertical farms have expanded rapidly in urban areas to support food system resilience. However, many of these systems obtain a substantial share of their material and energy requirements outside their urban environments with little integration into their urban environments. The aim of this study is to explore and outline the potential for developing more circular urban-vertical farming systems which integrate with buildings and employ residual material and energy streams from regional firms. We outline these potential synergies and assess the environmental performance through life cycle assessment, starting with a reference case and assessing the potential for different scenarios to improve urban farming performance and expand the potential product portfolio. Potential synergies with the host building and surrounding systems are explored through scenarios. The reference case is an urban farm located in the basement of a residential building in Stockholm. Synergies include the integration with the host building energy system, employing rainwater collection, solar panels for electricity demands from the farm, the use of residual materials from a local brewery, biofertilizers from urban food waste digestion, and integrated production of mushroom farming. Preliminary results suggest large environmental benefits from the integration of the urban farm with the building energy system, through the reduction of heat and electricity demand for the building. Similar results are seen from the use of residual materials from the brewery, which reduces growing media and carbon enrichment. No significant change in the environmental impacts were found from the use of wastewater or solar energy. The mushroom synergies also lead to large environmental impact reductions, primarily through the use of spent mushroom substrate and for carbon enrichment. The results from the synergies reviewed suggest that proximity and host-building synergies can improve the material and energy efficiency of urban vertical farms.