Vertical farming’s real problem is one number: kWh per kilo

On 3 August 2026, 80 Acres Farms told around 300 people to go home. This was a company that had raised $115 million the previous year, bought a biotech firm, merged with Soli Organic and picked up three of Kalera’s old farms after Kalera itself went under. Ten days before any of it was official, someone on r/verticalfarming posted that 80 Acres was a sinking ship: debt, unpaid vendors, layoffs. The forum beat the press release by a week and a half.

Then came the write-ups, all saying the same thing. The economics didn’t work. Which is true, and also useless: it’s like saying a restaurant closed because it ran out of money. I want to talk about the number sitting underneath that sentence instead, because it is the same number every time, and outside the industry almost nobody has heard of it. Kilowatt-hours per kilogram.

Kilowatt-hours per kilogram (kWh/kg) measures how much electricity a farm burns to grow one kilo of food. In a vertical farm that covers the LED lights, the air conditioning, the dehumidifiers and the pumps. Multiply it by whatever you pay for power and you get the electricity cost buried inside every kilo you sell.

Get that number wrong and nothing else you do will save you.

Table of contents

1. What a kilo of lettuce actually costs to grow
2. Where the electricity goes: lighting versus HVAC
3. The same farm is profitable in Iceland and bankrupt in Ohio
4. Vertical farming versus greenhouses: the limit nobody talks about
5. How the surviving farms are cutting kWh/kg
6. FAQ

What a kilo of lettuce actually costs to grow

Well-run vertical farms growing lettuce use 10 to 18 kWh per kilo, according to a 2025 benchmarking review by Miserocchi and Franco in Thermal Science and Engineering Progress. That is the strong end of the industry. The 2021 Global CEA Census put the average across facilities at 38.8 kWh/kg, which gives you some idea of the distance between the farms that have this figured out and the ones still paying to find out.

A kilo of lettuce, for reference, is mostly water and sells for a few euros.

The uncomfortable version comes from a 2025 paper in Plant Physiology, where Lovat, Noor and Milo worked through the thermodynamics and found that vertical farms convert purchased electricity into edible biomass at an efficiency of about 1% to 2%.

One percent.

So for every hundred units of electricity you buy, one ends up as something a person can eat. The other ninety-nine turn into heat, which you then pay again to remove from the building.

The same authors put a price on it. Electricity alone in vertically farmed staple crops works out to about $10 per kilo of dry matter, against a farm-gate wheat price under $1. Their verdict on growing wheat, rice or soy in a tower is one of the bluntest things I have read in a journal: the costs run “1 to 2 orders of magnitude” above field production, with no foreseeable route to fixing it.

Leafy greens and tomatoes come out far better, at about $0.50/kg. Which sounds survivable, until you notice that electricity is the only cost in that number. Nothing in there for rent, staff, seeds, packaging, delivery vans or whoever runs payroll.

Where the electricity goes: lighting versus HVAC

Two systems eat almost all of it. Lighting takes somewhere between 46% and 75% of total consumption, which makes sense once you accept that you have replaced the sun with a ceiling and the sun was free. HVAC takes 22% to 52%.

The HVAC half is the one people underestimate, so let me be precise about what is happening in that room.

Your LEDs are not only making light. They are making heat. Your plants, meanwhile, are transpiring, filling a sealed space with water vapour. So you install cooling to pull out the heat your lights just made, and dehumidifiers to pull out the moisture your plants just made, and all of it draws from the same meter.

You pay once to make the light. Then you pay again to clean up after it.

Which is why buying better LEDs is less boring than it sounds: every watt that doesn’t leak out as heat is a watt you avoid spending twice. It’s also why pushing light intensity to chase yield can quietly lose money, since you get slightly more lettuce and a considerably larger cooling bill. The same physics applies at home with smaller numbers, and I went through the options in my guide to LED grow lights.

The same farm is profitable in Iceland and bankrupt in Ohio

kWh/kg is a property of your technology. Your electricity price is a property of your postcode. The second one varies more than the first.

Take a competent farm running at 12 kWh/kg, well inside the strong band, and move it around.

The €0.111 figure is the assumption used in the Frontiers study cited below. The other two rows are illustrative arithmetic to show the spread, not quoted tariffs.

Now set that against the target. Meeuws and colleagues, writing in Frontiers in Sustainable Food Systems this year, calculated what vertical lettuce needs to cost to compete: €1.67 to €3.26 per kilo, everything included. Building, staff, seeds, packaging, all of it.

At €0.25/kWh, that farm has spent its entire cost budget on electricity before paying a single human being. Same equipment and same crop as the farm in Norway that is doing fine. Different grid.

So “vertical farming doesn’t work” is the wrong sentence. It works where power is cheap and produce is expensive. It fails where power is expensive and produce is cheap. Ohio, where 80 Acres built its business, is not a cheap-power, expensive-lettuce sort of place.

If you want to run this against your own tariff instead of mine, that is exactly why I built the Vertical Farm Cost Calculator. Put your local power price in and watch the verdict flip.

Vertical farming versus greenhouses: the limit nobody talks about

Here is the part that changed how I read this whole sector, and it is not flattering.

Miserocchi and Franco also asked a more interesting question than “what do farms use today”. They asked what the best possible number would be: where kWh/kg lands after the LEDs, the climate control and the control software have all improved as far as anyone currently expects them to. Their answer is 3.1 to 7.4 kWh/kg. That is the floor. No amount of further engineering takes you below it.

A Dutch high-tech greenhouse grows lettuce today, in 2026, with no breakthroughs required, at 3.81 kWh/kg.

Put the four numbers in one place and the argument makes itself:

The best case for vertical farming lands more or less where greenhouses already sit. Not ahead of them. Level with them, after the industry solves problems it has not yet solved, at commercial scale, consistently.

The Frontiers team reaches the same place from the cost side. Their competitive target of €1.67–3.26/kg brackets the Dutch greenhouse benchmark of €2.35/kg. Parity, in other words, and only if operators hit light-use efficiencies of 1.4 to 1.8 g dry weight per mol of PAR, a level the authors say has “not yet been demonstrated consistently at full commercial scale.”

Which leaves an awkward question about what the €200 million was supposed to buy.

There are decent answers to that. Land near cities, water use, no pesticides, growing in places where a greenhouse can’t go, total control over the crop. Several of those are worth real money, and I went through where each one wins in indoor vs outdoor farming. But “much cheaper than a greenhouse” was never on that list, whatever a decade of pitch decks implied.

How the surviving farms are cutting kWh/kg

The useful thing about this number is that it moves, and the farms pulling it down are not doing anything exotic.

In January, an operator posted their 2025 result on r/verticalfarming: down from 20 kWh/kg to 11. It became one of the most upvoted things the subreddit saw all year, which tells you what that audience genuinely cares about.

Run the arithmetic on it. At €0.25/kWh they went from €5.00 to €2.75 of electricity per kilo, so €2.25 came off every kilo they sell, without moving country, buying a building or raising a round. That is the distance between two rows of the table above, at the same address.

Four things move the number, in rough order of how much they matter:

• Light-use efficiency. The Frontiers paper is unambiguous that this is the dominant cost driver. More grams of crop per mol of light, rather than more light.
• Getting the heat out cheaply. Unglamorous, rarely the subject of a conference keynote, and where a large share of the HVAC bill hides.
• Crop choice. Herbs, microgreens and berries carry a price per kilo that can absorb the energy cost. Lettuce only barely does. Wheat never will.
• Where you plugged in. This one sits underneath the other three. Still the biggest single lever, and the only one you cannot retrofit later.

Why scale was never the answer

Notice what is not on that list: scale.

80 Acres had scale. A decade of operations, farms across several states, $115 million raised in its final year. None of it changed the physics of the room. kWh/kg is set by your equipment, your crop and your building, and growing the company does not improve any of the three.

That matters, because scale was the entire plan. The pitch across this industry was always that the unit economics would come good once volume arrived, the way they do in software or manufacturing. Build enough farms, the argument went, and the cost per kilo falls until it clears the supermarket price.

But a farm losing money on every kilo does not stop losing money by growing. It loses money on more kilos, faster, with a bigger fixed cost base sitting underneath it. Scale multiplies whatever margin you already have. When that margin is negative, scale is how you go bankrupt on schedule.

FAQ

Lorenzo Russo makes FoodLore from Sardinia, Italy. Former pasta maker, current food tech obsessive. Has now spent an unreasonable share of his life converting other people’s press releases into kilowatt-hours.

Sources: Lovat, Noor & Milo (2025), Plant Physiology, doi.org/10.1093/plphys/kiaf056 · Miserocchi & Franco (2025), Thermal Science and Engineering Progress 58, 103165 · Meeuws et al. (2026), Frontiers in Sustainable Food Systems 10:1833809 · 2021 Global CEA Census · 80 Acres Farms shutdown coverage, 3 August 2026.