Contents 1 INTRODUCTION
Ensuring global food security with a growing population in an uncertain world is an important challenge. Cities are responsible for approximately 70% of total global energy usage which places a significant strain on the earths resources (Musa 2018). Agriculture, particularly transport and storage, uses a significant proportion of energy (Smith et al. 2005), as well as consuming land and degrading the wider environment. At the same time consumers demand higher quality nutrition. Technology is an important means to increase the quantity and quality of production. An attractive concept is situating farming inside cities and using various technologies to scale up the potential yield and feed large numbers of people (Despommier 2013). Vertical farming is a technique in which stacked units are used to grow food indoors with hydroponics, LEDs, and robotic material handling systems; in a closed system the growing environment can be adjusted in real time to tailor production to precise specifications (Castelló Ferrer et al. 2019). Having intensive production taking place physically close to the concentrated consumption of the produce can reduce transportation and storage requirements; there are also further benefits from releasing agricultural land outside cities from the burden of agriculture. A higher quality and more customized product is possible because of elimination of pesticides and contamination from pollution. Diversification of the type of produce can be matched to the needs of local consumers at a finer level of granularity than is possible in traditional agribusiness models. Intergovernmental organizations such as the World Bank (World Bank 2017), the EU (Lohrberg et al. 2016), and others have recently promoted initiatives that include urban agriculture for these types of reasons.
