Image Source - Farm.One
This is part 2 of Indoor Farming’s Need for Life Cycle Assessments (LCAs). Part 1 can be found here.
A recent study by IVL Swedish Environmental Research Institute and KTH Royal Institute of Technology showed that most current vertical farming systems employ linear approaches to their production. This means that they use imported (often virgin) materials from outside their immediate regions for all their resource and energy demands. "Employing LCAs may be an essential methodology for IVFs to meet the criticism of many of the claims in the industry and provide knowledge for working with sustainability more strategically, providing transparent and scientifically based metrics".
A study by MDPI was carried out to assess the environmental impact potential of indoor farms. In it, they mapped out what a typical LCA may look like for an indoor farm, as shown below. As exemplified, the LCA was able to weed out the opportunities for operational improvement. As expected, energy use for lighting, temperature control, and irrigation were the largest contributors of GHG emissions usage. From here, they were able to break down further by utilizing studies that from an operational expenses perspective, the indoor farm was spending the most money on lighting, cooling vents, and heating. Combining these two pieces of information, MDPI was able to conclude that vertical farms’ energy use and operational light consumption were the keys to reducing GHG emissions.
For this example, MDPI created a universal metric such as CO2eq per kg of sellable produce. Doing this allows the LCA to be used to compare the impact of different growing systems, nutrient inputs, delivery mechanisms, but with the same functions and outputs. “This approach can also be used to optimise different characteristics such as spatial efficiency or growth speed, all within the context of seeking to minimise emissions.”
An example of an indoor farm that completed an LCA and publicly released it is Local Bounti. Their team looked into the environmental impact from the growth of lettuce in a traditional farm, a greenhouse, and a vertical farm setting. The comparison was then used to address the energy use for growth and transportation, water use, and waste for each method. Through it, they were able to see where they may be contaminating water and producing waste, among other things. While there could be slightly more granularity in this public report, we do recognize that Local Bounti has taken steps to incorporate their learnings into their business. They recently announced the implementation of their “Stack & Flow TechnologyTM, which continues to underpin our business model with a capital efficient tool to enhance crop turns and maximize return on investment across a variety of CEA approaches [which first takes into consideration a growing] site's greenhouse footprint.
Ultimately, status quo for indoor farms is to go linear. It works for many. But for those that do decide to go closed-loop, an LCA can help make clear where opportunities for savings lie and ways to advance climate-smart agriculture further. Knowing the difference between the two is also important, and so we’ve provided some examples below which could help as starting points for indoor farms that do want to transition:
Linear Indoor Farms:
- Nutrients and grow media are manufactured in foreign countries from non-renewable resources with detrimental environmental impact (eg: mineral salts and rockwool).
- Agriculture inputs shipped to regional distributor, then to wholesalers/retailers, then to farm.
- Farm uses hydroponic nutrients in a drain-to-waste system, polluting the local ecosystem.
- Farm pays company to dispose of spent germination grow media, which is then taken to a landfill.
Closed-loop Indoor Farms:
- Nutrients and grow media are manufactured locally/regionally from renewable sources with positive environmental impact (eg: fibers from crop residue).
- Agriculture inputs shipped directly to farm with smart, efficient, and sustainable packaging practices that save fuel and materials.
- Farm uses nutrients recovered from sterile and consistent waste streams in recirculating system, minimizing runoff, then uses spent solution on nearby soil plots.
- Farm composts spent germination grow media and adds it to nearby field plots to build soil.
- Organic waste from the production process, may be sent to local/regional manufacturer to produce additional products.