How can the energy use and cost of indoor farming be reduced?

Plant factories and vertical farms grow crops under LEDs with little water or land, but they must buy all the light that fields and greenhouses get free from the sun. Energy use and cost decide whether indoor farming can move beyond leafy greens.

Question

How can the excessive energy consumption and high costs of controlled-environment agriculture be addressed? This covers lighting efficiency, climate control (cooling, heating, dehumidification), crops and plant traits suited to indoor growth, integration with renewable energy, and the economics of plant factories, vertical farms and greenhouses.

Background

The question is in the theme "enabling smart and controlled-environment agriculture for food security" of the 100 essential questions for the future of agriculture, compiled from 419 questions submitted worldwide in 2022. The authors note that renewable energy can reduce pollution and keep the energy supply of such systems secure [1].

What is known

• Closed plant production systems use water, CO₂ and light energy much more efficiently than greenhouses, but there is much more room to improve their light and electric energy use efficiency [2].
• Modelling lettuce production at 24–68° N, a plant factory needed 247 kWh of purchased electricity per kg of dry weight, against 70–211 kWh in greenhouses in the Netherlands, the United Arab Emirates and Sweden, which use free sunlight; in overall energy efficiency, however, the plant factory (1,411 MJ per kg) outperformed even the most efficient greenhouse (1,699 MJ per kg) [3].
• LED efficiency is approaching physical limits: with current technology, fixture efficacy is limited to about 3.4 µmol per joule for white-plus-red and 4.1 µmol per joule for blue-plus-red fixtures [4].
• Mainstream adoption of vertical farming will require improvements in profitability, energy efficiency, public policy and consumer acceptance; current systems grow a limited range of crops [5].

What would count as progress

No single result settles a question like this; contributions like these would move it forward:

• Open, measured energy and yield data from commercial indoor farms (kWh per kg of produce), broken down into lighting and climate control.
• Varieties bred for indoor conditions, such as higher light-use efficiency, compact growth and faster cycles, with gains reported in kWh per kg.
• Techno-economic analyses that include renewable supply and waste-heat use, validated against operating facilities.

References

1. Hu, Y. et al. (2023). 100 essential questions for the future of agriculture. Modern Agriculture 1(1), 4–12.
2. Kozai, T. (2013). Resource use efficiency of closed plant production system with artificial light: concept, estimation and application to plant factory. Proceedings of the Japan Academy, Series B 89(10), 447–461.
3. Graamans, L. et al. (2018). Plant factories versus greenhouses: comparison of resource use efficiency. Agricultural Systems 160, 31–43.
4. Kusuma, P. et al. (2020). From physics to fixtures to food: current and potential LED efficacy. Horticulture Research 7, 56.
5. van Delden, S. H. et al. (2021). Current status and future challenges in implementing and upscaling vertical farming systems. Nature Food 2(12), 944–956.

Source

Imported from 100 essential questions for the future of agriculture, question 71, curated by Hu et al. Listed as open in the source (2023) and still an active research question as of 2026-10-20. The statement above is written in our own words; see the source for the original wording, history and discussion.