Human development has posed unprecedent pressures on overall natural systems due to extraction, conversion and inefficient use of key resources, as Water, Energy and Food (WEF). Cities provide support functions to more than half of the world population, and are promoters of unsustainable use of WEF resources, acting as a negative multiplier effect along supply chains. An increasing pressure to transform cities as beacons of sustainable development (eg C4O or CoM) to envisage carbon neutrality and WEF resource security without compromising social-economic prosperity. Self-sufficiency has been adopted as a driver for sustainability. That concept is generally taken to mean the extent to which a system (e.g. country, city, building) can satisfy its needs from its own domestic production, based on endogenous resources. A building may have the ability (e.g. insulation measures, solar energy) to provide the services needed (e.g. space heating) while avoiding the resorting to external resources (e.g. natural gas). Self-sufficiency analysis in cities on food and energy, have developed through a silo approach. Issues like the competitive use of available space in the city to provide energy and food is not prevented, nor the consumers profiles, are some examples hampering the full potential of cities. Resource assessment has failed holistic approaches. Food provision highly depends on energy for food production, transport and refrigeration, and on water for irrigation and cooking, being these interconnections missed in almost all analysis. Energy and water services currently present high carbon footprints but a high decarbonization potential exists (e.g. electric or green hydrogen-based vehicles, and renewables). Consumer profiles, as diets’ options and rational use of energy and water, and families income are usually also missing in integrated resources assessment. Moreover, impacts from climate change may compromise current practices and alternatives, as expected water shortage in some regions (e.g. Iberia) and efficiency reduction of cost-effective solutions (e.g. solar PV panels due to heat waves). Recent research [5] on WEF nexus adopted static assessments, limiting its contribution towards prospective analysis which is essential for preventive policy making and investments. Increasing self-sufficiency to a maximum extent may come to represent a long-term burden for sustainability, due to additional inefficiencies and impacts on ecosystems, if an integrated and prospective approach misses its assessment.

CitySelfy will focus on WEF resources use within the city boundaries, explicit its interlinkages, to show how and at what extent healthy food, safely managed water and affordable, reliable and modern energy services can be provided endogenously to its inhabitants, without hamper the city sustainability in the future. Self-sufficiency will be used to push the research to the frontier of natural resource use management, for example by changing the paradigm from centralized and rural productive models to city-families based ones, and by adopting innovative consumer profiles. CitySelfy will advance over the question: at what extent WEF self-sufficiency may act as a driver to achieve the city sustainability? Our hypothesis states self-sufficiency has positive impacts on sustainability triggers, even under climate change scenarios, as climate mitigation and resilience, employment and families’ welfare, among others, within the city boundaries, at least at certain extent. CitySelfy will expand a peer-reviewed technology-based Energy system optimization tool, applied to the municipality of Cascais, to include interlinkages with Water and Food resources, technologies and practices, while taking social preferences and economic profiles of its inhabitants. A structured survey will portray this information, as well as their willingness to accept and pay consumer changes and new technologies and products (e.g. food from environment controlled urban farming). These results will inform WEF demand scenarios and local production potential, to feed the optimization tool. Several levels of self-sufficiency, and climate changes impacts projected for the region, will be tested, and its impact in city sustainability assessed taking social, economic and environmental indicators (e.g., employment, families’ welfare, carbon emissions and land use). Key outcomes include future optimal configurations for the WEF systems up to 2070 (e.g. decentralized power, urban farming systems, water harvesting solutions), corresponding to different levels of sufficiency and sustainability. Through the demonstration of cost-effective and social sound opportunities for the city, discussed with key stakeholders, the societal impacts of CitySelfy includes what to deploy (innovators), where and when to invest (investors), and how to promote (public policy makers) carbon neutral, climate resilient and sustainable WEF systems.