Authors: Jamie Burrows (Founder & Chief Executive Officer), Dr. Marco Ferroni (Chairman), Dr. James Stevens (Senior Plant Scientist), Tom Bennett (Plant Scientist).
As the world reflects on the outcomes of last week’s United Nations 2023 Water Conference in New York, one thing is clear: there cannot be lasting food security for all without much greater water use efficiency in the production, transformation, and distribution of food.
Agriculture is the largest water use sector in the global economy, responsible for 70 percent of all water withdrawals(1). But up to half of that water is ‘wasted’(2): it is not taken up by crops or livestock but evaporates from bare soil or runs off into rivers as wastewater, causing pollution downstream.
This isn’t sustainable today and will be even less so going forward. The global demand for water is set to increase by 20-30% by 2050 as population growth, urbanisation, and rising affluence drive dietary preferences and push up the demand for food(3). The supply of water will at the same time become more erratic in many regions as groundwater resources deplete while river and lake levels fluctuate(4).
Climate change due to planetary warming is real and deeply interacting with water, agricultural prospects, and food. Agriculture has always been challenged by too much water when not wanted and too little when needed, but the frequency and intensity of adverse events is getting worse.
For instance, Californian strawberry fields flooded earlier this month causing hundreds of millions of dollars in losses to growers. While further damage suffered from wind, rain, and floods occurred in December last year, wildfires and drought in the State were a hazard to humans, plants and animals alike in 2020 and 2021(5),(6),(7).
Water anomalies and their effects on the availability of food affect communities in the Middle East and the Horn of Africa, among many other parts of the world, and may have played a role in the widely publicized chain of events emptying vegetable shelves in supermarkets in the UK. Challenges related to water, agriculture, and food will become more pronounced in the years ahead.
Silver bullets to solve the water crisis do not exist but there are many opportunities for action recognised in the Water Agenda the UN Conference proposed(8). Investment in water infrastructure, storage and precision irrigation is key, along with innovation in water governance, demand management, and supporting technologies and tools. Food security depends increasingly on transforming water use in the farming and food value chains.
Controlled environment agriculture (CEA) offers game-changing opportunities in this respect. Vertical farming systems save at least 90% of the water used to produce the same crop yield in conventional (outdoor) production(9). Water in closed systems that would otherwise evaporate can be recovered and water used for irrigation can also be recirculated, filtered, treated, and reused many times, with nutrients added to ‘replenish’ each cycle. The water-use and resource-use efficiency of vertical farming make the method a necessary viable and scalable answer to many of the stability and sustainability challenges troubling food systems. Vertical farming and other methods of CEA will never fully replace outdoor agriculture but will increasingly become mainstream as a complement to it with very significant environmental, food production, and food security benefits.
Vertical farming saves not only water but land as well. Multiple layers of crops on a small footprint and very high annual yields involving multi-cropping under controlled conditions can sometimes exceed 1,000 times the yield achieved on the same surface area of conventional outdoor production(10). Land saving (taking land out of farming, allowing regeneration and rewilding) can also carry huge environmental benefits, not least in relation to water management and conservation, but also in terms of encouraging ecosystem services and improvements in biodiversity. And this is not all. Further benefits of production in a controlled environment include crop health and food safety. Careful design and operating procedures controls contaminants, pests and diseases in systems which are soil free and do not need chemical pesticides, fungicides, or herbicides.
Furthermore, vertical farming has a beneficial role in nutrition and health. Malnutrition is common to both advanced economies as well as developing nations with poor access to fresh produce, resulting in ill-health from micronutrient deficiencies constituting significant and costly global public health risks(11). A major reason underpinning this situation is the lack of daily access to or excessive cost of healthy and diversified diets in cities and urban areas, including vegetables and other micronutrient-rich foods. Vertical farming can play a major role in addressing this shortfall by ensuring regular and predictable supplies of fresh produce near points of consumption, unaffected by seasonality and uncertain production linked to the vagaries of nature encountered in the field.
A key point for sustainable food systems is to increase their resilience. As events have shown in the UK, where tomatoes, peppers and cucumbers became unavailable this winter(12), we have a food system that is prone to collapse in the face of price and environmental shocks, is unable to shift production to alternative venues and where market power is highly concentrated. In the face of these challenges, vertical farms, which can be rapidly deployed near population centres, can improve resilience by diversifying production locations, can deliver crops year-round at consistent prices, can offer employment and appropriate technology transfer and can do so at scale in a distributed network that is robust to shocks(13). With the high level of control over inputs and new varieties optimised for vertical farm production, crops can be at least as nutritionally complex and flavourful as anything grown outdoors(14), with fewer losses to disease and greater safety to consumers. Therefore, vertical farms should be at the nexus of improved food systems and able to make a significant contribution to improving otherwise intractable public health crises.
Energy consumption is also a frequently discussed issue in indoor farming. Clearly, powering LED lights plus temperature and humidity control are always going to be more expensive compared to outdoor grown crops where these factors are free. However, using different wavelengths of light through a crop’s growth cycle can have a marked impact on not only energy consumption but also influence plant morphology, taste, and nutrient concentration(15). The ability to manage the growth environment through technology and crop science will continue to improve the unit economics of vertical farms. And it’s important to remember that outdoor grown crops do use energy (ploughing, tilling, spraying fertilisers & pesticides, harvesting etc.), the supply chains associated with them use even more (and result in poor crops), and the chemicals applied are almost all sourced from fossil fuels. The key metric that we look at from an industry standpoint is how much energy is required to produce 1KG of a crop and more importantly, where is the energy sourced from. If we can get to a position where all energy used to power indoor farms comes from renewable sources of energy and/or energy from waste (which is already policy in many countries), then the question of energy almost entirely falls away. An important consequence of the move to renewables is the increased certainty of energy costs, which are now comfortably lower than fossil fuel-powered electricity systems(16).
Using renewable energy makes a significant difference to carbon dioxide emissions of course. But what about all other greenhouse gas emissions from CEA food production and indoor vertical farming in particular? Three aspects of emissions must be considered. There are those emissions related to the building of a vertical farm such as the production of steel or LEDs; there is the operation of a farm over its lifetime, and there is the carbon released in de-commissioning a farm at the end of its life. A Life Cycle Assessment (LCA) brings together these measurements and compares them to a baseline such as outdoor farming(17). Based on our own data, the emissions from the construction phase are a relatively small contributor overall. Most emissions happen in the operation of a vertical farm (which is effectively an up to 50 year asset, overall), primarily from supplying energy for lighting, temperature and humidity control. Efficient use of fertilisers significantly reduces the harm from this source. End-of-life emissions are also relatively small. In addition, land use change as discussed above makes a large difference to the carbon balance.
Vertical farms were pioneered in the US and Asia in the last decade or so. And it is in the US that the largest investments in the sector have been made – up to 2 bn USD by 2022. However, the last twelve months have unfortunately seen a range of high-profile failures and retrenchments. To some extent these cases have been laid at the door of Silicon Valley investors expecting biotech returns for farming businesses.
At Vertical Future, we design and build systems that offer bond-like returns: renewable energy contracts, hedged steel prices and long-term offtake agreements secured with downstream customers. This approach is not as sexy as biotech, but it is much closer to traditional agriculture, with its focus on long-term agreements, trust-building and appropriate hedging of risks against physical delivery of goods. We work with our clients to build viable businesses through hardware and software engineering and plant science.
The effects of surging commodity prices and climate change on food cost and availability are now abundantly clear. Our experience has been that major food retailers and distributors globally have been forced to rethink their planning and buying policies. It is clear to us that vertical farming is poised to become part of the solution that delivers inexpensive food to all that need it, consistently and at high quality. Vertical farming also delivers fair returns to farmers, and helps reduce human impact on resources, particularly land, and water. As such, the technology is well-suited to locations that are water-constrained, have little agricultural land and have sources of renewable energy. The Middle East and North Africa is one such region. But with ongoing urbanisation, the need to supply fresh produce into ever larger cities is not going to disappear, and many other regions are sure to need vertical farms.
Vertical Farming is not the solution but a solution among many that will help deliver the sustainable development goals for all. Of all those goals, clean water is becoming the most critical for ongoing human existence, as confirmed at the UN Water Conference. Given modern agriculture’s profligacy with water, CEA and vertical farms offer a means of reducing usage that is affordable, scalable and profitable.
1. https://www.worldbank.org/en/topic/water-in-agriculture. Accessed 28/03/2023
2. Gleick, P.H., 1993. Water in crisis (Vol. 100). New York: Oxford University Press.
3. https://unesdoc.unesco.org/ark:/48223/pf0000384659. Accessed 28/03/2023
4. https://www.cfr.org/backgrounder/water-stress-global-problem-thats-getting-worse. Accessed 28/03/2023
6. https://earthobservatory.nasa.gov/images/150823/storms-soak-california. Accessed 28/03/2023
8. https://sdgs.un.org/partnerships/action-networks/water. Accessed 28/03/23
9. Barbosa GL, Gadelha FD, Kublik N, Proctor A, Reichelm L, Weissinger E, Wohlleb GM, Halden RU. Comparison of Land, Water, and Energy Requirements of Lettuce Grown Using Hydroponic vs. Conventional Agricultural Methods. Int J Environ Res Public Health. 2015 Jun 16;12(6):6879-91. doi: 10.3390/ijerph120606879.
10. Zielder, C. & Schubert D., 2014, From Bioregenerative Life Support Systems for Space to Vertical Farming on Earth – The 100% Spin-off, Life in Space for Life on Earth Symposium (2014), Waterloo, Canada
11. https://www.who.int/news-room/fact-sheets/detail/malnutrition. Accessed 28/03/23
13. Nolte K., & Ostermeier M., 2017, Labour Market Effects of Large-Scale Agricultural Investment: Conceptual Considerations and Estimated Employment Effects, World Development, 98, 430-446
15. Pennisi, G., Blasioli, S., Cellini, A., Maia, L., Crepaldi, A., Braschi, I., Spinelli, F., Nicola, S., Fernandez, J.A., Stanghellini, C. and Marcelis, L.F., 2019. Unraveling the role of red: blue LED lights on resource use efficiency and nutritional properties of indoor grown sweet basil. Frontiers in plant science, 10, p.305.
16. https://www.irena.org/Publications/2022/Jul/Renewable-Energy-Statistics-2022. Accessed 28/03/2023
17. https://www.iso.org/standard/38498.html. Accessed 28/03/2023 Casey, L., Freeman, B., Francis, K., Brychkova, G., McKeown, P., Spillane, C., Bezrukov, A., Zaworotko, M. and Styles, D., 2022. Comparative environmental footprints of lettuce supplied by hydroponic controlled-environment agriculture and field-based supply chains. Journal of Cleaner Production, 369, p.133214.