The potential role of Vertical Plant Farms in contributing to the environmental sustainability and security of the global food system

Vertical plant farms (VPF), or more colloquially ‘vertical farms’ or ‘plant factories’ are innovative indoor crop production structures utilising the vertical dimension of space, usually with the application of artificial lighting and soil-less growing media. There has been significant interest in the virtues of VPFs in the context of environmental sustainability and resource use efficiency in recent years. VPFs have been demonstrated to utilise significantly less land, fertiliser, water and pesticides than conventional counterparts. Furthermore, VPFs’ climate-independent nature has the potential to increase national food security, reduce global supply chains and potentially reduce susceptibility to the effects of climate change. The global food system is highly damaging to the natural ecosystem and contributes considerably to global carbon emissions. Furthermore, there is a lack of mitigation strategy for the effects of climate change on food systems, which are already reporting to be having a negative effect on global production. VPFs might offer a solution to many of these challenges. However, the current VPF economy remains niche, producing very small volumes of low-energy density fresh crops such as salad leaves and microgreens. These crops have short life cycles, high commodity values and low energy density, key factors which make them the most viable crops for VPF cultivation. Capital costs, energy density and the resulting carbon intensity and production costs are significant barriers to producing crops such as cereals, legumes, roots and seed oils in a VPF setting. Many of these important crops, both in terms of contribution to calories within the human diet, and in terms of area of global cropland utilised are effectively ‘blacklisted’ in the VPF commercial sector and research community. This research aims to investigate to what extent VPFs can have a greater role in contributing to the security and environmental sustainability of the global food system both currently, and in the future. No such research exists which has aimed to quantify key outputs for a wide range of crops in a VPF. This data might be important to inform on what conditions would be required to increase the viability of VPF crops, and to evaluate to what extent many of these important crops are unviable. A biomathematical model of a theoretical monocrop VPF has been developed utilising a novel approach which predicts key outputs for VPF cultivation for 52 of the most important food crops in the global food system. These factors include yield, detailed economic outputs, and environmental sustainability indicators including gross and net carbon footprint, water footprint and land use efficiency. Input data is varied during simulations in two distinct scenarios; a baseline covering the period 2021-24, across ten global sample cities, and a 2040 scenario where favourable, but realistic variables are input into the model to quantify both economic viability and environmental sustainability. In the baseline scenario, viability of most crop systems is extremely low. Most crops fail overall viability due to high carbon intensity, driven by high electricity carbon intensities. Only Oslo, Manchester and San Jose (Costa Rica) have crops meeting environmental sustainability criteria, highlighting how crucial low carbon electricity is for VPF crop viability. The economic viability is quantified by the economic viability ratio (EVR) where the production costs in the VPF are compared to global median FAO producer prices. The cost of electricity is the most significant factor influencing EVR, which is highly influenced by both LED lighting and HVAC. Cities with low electricity rates, and low staffing costs performed best (Buenos Aires and Mumbai). HVAC energy intensity is higher in hot and humid climates, though low-cost electricity in these cities often masks this effect. The best performing crops are, as expected, fruits from small plants, leafy greens and herbs. The crop-specific factors influencing EVR are high harvest index, high water composition of the harvestable component and the commodity cost of the crop. In the 2040 scenario, 23 of the 52 sample crops achieve overall viability. The reduction in both electricity cost and carbon intensity ($0.01 and 15g CO2e/kWh respectively) significantly reduce the carbon intensities of production and production costs of all crops, however 29 crops, mainly cereals, legumes and oil seeds, remain economically unviable. At this input electricity carbon intensity, most crops are, however, environmentally sustainable. In the 2040 scenario, approximately 4.13% of the global food system by area of cropland is deemed potentially viable for VPF cultivation. In a theoretical scenario where these crops are removed from conventional cultivation systems and exclusively cultivated in VPFs, the result at a global level would be a reduction in carbon emissions of 1.2 billion tonnes, a reduction in global agricultural water withdrawals of 16.25% and a reduction in cropland of 61.28 million hectares. However, 232,000 VPFs would need to be constructed at an estimated cost of $10.43 trillion. Furthermore, global electricity generation would have to double to meet VPF demand. The extent to which VPFs can contribute to food security and environmental sustainability is limited by the scope of crop diversity. Human diet is highly biased towards energy-dense crops such as cereals and legumes. These crops are expensive to produce in a VPF and have a low commodity value. In the current agricultural system with highly efficient mass production of low-cost food, but high environmental impacts, VPF cannot economically compete. However, as demonstrated in the 2040 scenario, if innovation in electricity generation decreases the cost and carbon intensity, the scope of VPF crop diversity can increase, and the environmental benefits might be realised.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

2025

Author dc:creator

• Turner, David

Licence

• https://dora.dmu.ac.uk/bitstreams/f95a12e7-d108-44e7-aef9-fd8ece93e7e3/download