The 2050 decarbonization goals coupled with the growing housing shortage in Europe intensify the pressure on new-build dwellings to enhance their energy performance. Beyond a zero operational energy, the focus has shifted towards reducing embodied carbon (EC). Against this backdrop, this study investigates the simultaneous impact of downsizing and the use of timber in new-build dwellings, EC reduction strategies seldom explored concurrently. Through partial life cycle assessments, three scenarios are modelled: the Small, Medium, and Large House, with two construction variations for each, comparing a modular timber design to a conventional concrete alternative. Designs are based on dwellings built in Almere, the Netherlands. Data is extracted from the Swiss Ecoinvent database using the TOTEM tool and the static −1/+1 approach for biogenic carbon accounting is adopted. Results show a total EC ranging from 42,608 to 70,384 kgCO2eq for the timber designs versus 54,681 to 91,270 kgCO2eq for their concrete counterparts. Findings suggest that the relationship between house size and EC is sublinear whereby a house twice the size entails less than twice the EC emissions. Only the simultaneous implementation of downsizing and the use of timber achieved 53% carbon savings. The discussion explores implications of outcomes across academic, industry and policy perspectives, challenges in implementing smaller timber dwellings, and study limitations and future research. Beyond its empirical contribution, this paper offers a practical contribution with its hierarchical data analysis approach covering building, element and component. This approach can be implemented by researchers and practitioners alike to inform their design process.@en

The anthropogenic demand for food, energy and water (FEW) resources is growing, changing and increasingly concentrating in cities due fast urbanisation worldwide. Carbon dioxide emissions associated with the FEW supply infrastructure makes cities one of the main drivers of global greenhouse gas emissions. Urban food production (UFP) could potentially mitigate city’s carbon emissions by means of direct and indirect emissions cutbacks, respectively through proximity based advantages and recirculation benefits by integration with the urban resource infrastructure. The inherent complexity and comprehensiveness of food production makes it challenging to explore this method during the urban design process and provide holistic evaluations at an early stage. This research investigates how urbanising the production of food can mitigate the carbon emissions of urban communities. Along the principles of the FEW nexus approach to resource management, a method and platform have been developed that support professionals such as urban planners and designers with the exploration of urban food production in the design process. The aim of this work is to transform cities into more sustainable and resilient places to live. This work hypothesises that urbanising the production of food resources and making urban food production an integral part of the urban resources infrastructure can help the decarbonisation of cities. The objective of this work is to develop a protocol and platform for a non-expert, multi-disciplinary urban design team that can guide the implementation and evaluation of a food production system. The platform, which has been coined the FEWprint, should guide the agro-urban designer during the exploration phase of the design process by providing quantitative feedback on various relevant indicators. The following main research question has been formulated based on the problem statement, hypothesis, research aim and objective: How could the urban food production design process be harmonised with the FEW nexus principles in order to lower the carbon footprint of the city?... @en

The production, processing, and transportation of food, in particular animal-based products, imposes great environmental burden on the planet. The current food supply system often constitutes a considerable part of the total carbon emissions of urban communities in industrialised cities. Urban food production (UFP) is a method that can potentially diminish food emissions. In parallel, a shift towards a predominantly plant-based diet that meets the nutritional protein intake is an effective method to curtail carbon emissions from food. Considering the high land use associated with the production of animal-based products, such a shift will prompt a community food demand that is more inclined to be satisfied with local production. Therefore, during the design process of a future low-carbon city, the combined application of both methods is worth exploring. This work introduces, describes, and demonstrates the diet shift component of the FEWprint platform, a user friendly UFP assessment platform for designers that is constructed around the broader three-pronged strategy of evaluation, shift, and design. For three neighborhoods, in Amsterdam, Belfast, and Detroit, the contextual consumption and country-specific environmental footprint data are applied to simulate a theoretical community-wide diet shift from a conventional to a vegan diet, whilst maintaining protein intake equilibrium. The results show that in total terms, the largest carbon mitigation potential awaits in Detroit (−916 kg CO2eq/cap/year), followed by Belfast (−866 kg) and Amsterdam (−509 kg). In relative terms, the carbon reduction potential is largest in Belfast (−25%), followed by Amsterdam (−15%) and Detroit (−7%). The FEWprint can be used to generate preliminary figures on the carbon implications of dietary adaptations and can be employed to give a first indication of the potential of UFP in urban communities.@en

Current urbanization rates concentrate the ever growing demand for food, energy and water (FEW) resources particularly in cities, making them one of the main drivers of greenhouse gas emissions. The FEW nexus integrative approach offers a potential framework for sustainable resource management in cities. However, existing nexus evaluation tools are limited in application and often inadequate. This is primarily due to the FEW nexus intricacy, the tools’ operational complexity and/or the need to input comprehensive data that is often unavailable to users. Having outlined these current gaps, this paper introduces the FEWprint, an integrated carbon accounting platform that provides an accessible process for FEW nexus-based evaluations of urban areas. This spreadsheet-based framework is employed to calculate a consumption-based footprint derived from food consumption, thermal/electrical energy use, car fuel demand, water management, and domestic waste processing. A comparative assessment between six different communities reveals significant differences in total annual emissions. The food sector impact shows emissions ranging between 993Kg/cap∗yr and 1366Kg/cap∗yr in Amsterdam and Tokyo respectively, but is also the least deviating from all considered resource sectors. This holistic carbon footprint and considered food inventory will serve as a baseline for future integrated urban farming strategies and urban design proposals to be tested.

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Amsterdam aims to bring down its carbon footprint by 55% in 2030 and by 95% in 2050. For the built environment, plotted pathways towards carbon neutrality primarily revolve around the reduction of fossil based energy demand and the transition towards renewable energy production strategies. The consumption of food resources, and its significant corresponding carbon footprints, remain up to this day outside the scope of the city’s carbon accounting. At the interface of the building sector and the agricultural sector, under-explored possibilities for synergistic and sustainable resource management come to light. For a more holistic and veracious evaluation, this research expands the carbon inventory of the urban dweller with the food category and then explores, by means of a case study, a novel strategy for the decarbonisation of the built environment: urban pig farming in Amsterdam. A theoretical farming system is added to an urban context and coupled with the existing local resource flows, allowing for new output-input links. The capacity of the farm, i.e. the maximum number of animals at any time, is determined by the daily food waste output of the neighbourhood. A comparison is drawn with a conventional method for the energy transition: photovoltaic energy, for which two common array configurations are assessed. The three scenarios are evaluated on three aspects relevant to the energy transition of the built environment: avoided carbon emissions, produced thermal energy and produced electrical energy, normalised per square meter surface area. Carbon accounting shows that an integrated pig production facility of 495 m2, holding 79 animals, can potentially reduce the carbon emissions of Kattenburg by 218 tons (−5.6%) a year, i.e. 441 kg CO2/m2. The solar farm has a net impact of 42 kg/m2/yr if the panel array configuration is based on optimal panel angle and 77 kg/m2/yr if the configuration is based on optimal ground surface area cover. This study intends to spark further discussion on urban farming by showing that an integrated pig farm can potentially avoid between 6–10 times more carbon emissions compared to a solar farm.@en

The municipality of Amsterdam has set stringent carbon emission reduction targets: 55% by 2030 and 95% by 2050 for the entire metropolitan area. One of the key strategies to achieve these goals entails a disconnection of all households from the natural gas supply by 2040 and connecting them to the existing city-wide heat grid. This paper aims to demonstrate the value of considering local energy potentials at the city block level by exploring the potential of a rooftop greenhouse solar collector as a renewable alternative to centralized district heating. An existing supermarket and an ATES component complete this local energy synergy. The thermal energy balance of the three urban functions were determined and integrated into hourly energy profiles to locate and quantify the simultaneous and mismatched discrepancies between energy excess and demand. The excess thermal energy extracted from one 850 m2 greenhouse can sustain up to 47 dwellings, provided it is kept under specific interior climate set points. Carbon accounting was applied to evaluate the system performance of the business-as-usual situation, the district heating option and the local system. The avoided emissions due to the substitution of natural gas by solar thermal energy do not outweigh the additional emissions consequential to the fossil-based electricity consumption of the greenhouse’s crop growing lights, but when the daily photoperiod is reduced from 16 h to 12 h, the system performs equally to the business-as-usual situation. Deactivating growth lighting completely does make this local energy solution carbon competitive with district heating. This study points out that rooftop greenhouses applied as solar collectors can be a suitable alternative energy solution to conventional district heating, but the absence of growing lights will lead to diminished agricultural yields.@en