Vertical Farming: It Saves Water and Pays in Electricity

Imagine a loaf, or a bunch of leafy greens, grown on a metal shelf on a floor that no sun or rain reaches, with lighting and irrigation run by software that never sleeps. That is vertical farming. The question worth asking is not whether it works technically, for it does, but at what cost, for which crops, and on what land.

Professor Dickson Despommier of Columbia University developed, with his students over the decade before 2010, a vision of bringing agriculture into the heart of cities. The idea has a serious motive: in 2009 the Food and Agriculture Organization (FAO) said that feeding 9.1 billion people in 2050 would require raising food production by about 70%, and that output in developing countries would need to almost double. That is an estimate built on demographic and dietary assumptions, not a written decree, and what will come is known to God.

What the closed farm gains

A 2015 study by Barbosa and colleagues compared lettuce grown in closed hydroponic greenhouses with field lettuce in Arizona. Output was about 41 kg per square metre per year against 3.9 kg, and water use was roughly 20 litres per kilogram against 250. That is a large gain in a water-scarce land. But the same study found energy use per kilogram about 82 times higher (about 90,000 kilojoules per kilogram against 1,100). It compares a controlled hydroponic greenhouse with the field and does not measure a multi-storey vertical farm, so we read it as a sign of the direction of the trade-off, not a final verdict.

Electricity: the other side of the scale

The sun that the sky sends free to the field has to be generated indoors. A study led by Zoe Harris of the University of Surrey, published in Food and Energy Security in 2025, found that lettuce from a British vertical farm reached 4.71 kg of CO2 equivalent per kilogram in some scenarios, against 0.59 for the most impactful field farm in the sample (three farms in Britain and Spain). When renewable electricity was assumed, the figure fell to 0.93, still above the field farms. This is a single study with limits: it compares one particular farm in one particular climate.

Artificial intelligence helps with controlling lighting and irrigation and scheduling operations, but it does not change a law of physics: artificial light needs energy. At most it reduces waste.

What the companies said by going bankrupt

The weight of cost is shown by what happened to the sector's pioneers. A University College London (UCL) analysis in January 2025 reported that Plenty halted its farm in Compton, California, at the end of 2024 and blamed the rising cost of energy, that Bowery stopped operations late in the same year, and that AeroFarms, Kalera and AppHarvest declared bankruptcy within two years. The analysis pointed to general causes, among them the cost of energy, competition from cheaper traditional farming, and the rising cost of finance. It did not detail the differences between one company and another.

And in the Gulf?

According to the magazine AGBI, the Gulf has historically imported about 90% of its food, so it is natural that the idea attracts attention. The magazine reported that a project in Dubai backed by Emirates Flight Catering and Crop One aims to produce more than a million kilograms of leafy greens a year, and that two companies announced a vertical farm in Riyadh with a planned capacity of 2,000 kg a day. We found nothing confirming actual operation or actual cost, so we pass on the announcement, not an achievement. Perhaps the Gulf's advantage is its abundant sunshine, so solar power could ease the electricity burden; that is a logical inference, not a result measured in the sources we consulted.

How to read the promise

• Ask about electricity: how many kilowatt-hours per kilogram, and where from?
• Ask about the crop: leafy greens and herbs are fast-cycle and higher-priced, whereas wheat and rice do not justify this cost.
• Beware of marketing figures; some suppliers claim high water savings that no independent measurement supports.

Vertical farming is a real opportunity in its place, a tributary that complements the field and does not replace it. Whoever takes the means, and counts the whole cost before thinking well of the promise, has protected his money and benefited people.