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Comment by Chris2048 | Hacker News Reader

Chris2048

So, the plants are grown purely on LED light? What's the electricity cost per kg produce?

Plastic boxes of fancy salad mix cost about $32/kilo at my grocery store. At 15c per kwh that puts a limit of 213 kwh/kg to break even.

Here's an interesting angle:

What's the energy/kg to produce on site versus the energy/kg to grow a thousand miles away, transport and store, transport and store, transport to final destination?

You also have to add to the on-site the cost of not using that space for something else.

In that case, lets add the environmental and biodiversity costs of farmland.

Not at all. The farmland is highly unlikely to be used for any other purpose.

We're trying to make an apples-to-apples comparison here, not moral judgments.

Removing native flora and fauna and replacing it with domesticated varieties has a clear impact on the environment

What was the environmental impact of replacing whatever was in these urban environements with concrete, steel and asphalt?

Literally just looking at the economics here, I'll say again.

Of course that has an impact too; I hope you do realize the exploitation of and the health of the environment is actually very closely intertwined with the economy. There is fundamentally no way to "literally just look[] at the economics." All land use has an impact.

Un-used land serves a purpose for biodiversity and maintaining ecosystems and plays a role in the climate.

Deforestation for farmland has major implications here.

If you want to make and apples-to-apples comparison, you have to consider what turning a thousand square miles of forest into farmland does versus stacking these containers up.

This solution also claims to use 10X less water, so we can start to factor in energy use related to water production as well.

See my other reply about replacing whatever was in these urban environments before with concrete, steel and asphalt.

A fine argument to counter with, however when we look at population density, you'll see that the vast majority of concrete, steel and asphalt goes to support a tiny fraction of the number of people. Thousands of miles of roads... to connect just thousands of rural people.

Meanwhile, thousands of people can live in just a few acres in the city. Far more people per kg of asphalt and concrete!

Which is the kind of efficiencies you expect with economies of scale.

You'd be surprised how much asphalt and concrete we use to give every 500 person village roads and infrastructure!

Aren't you tilting the scale by assuming every m^2 farmland displaces m^2 forest?

If you want to every manufacturing side-cost (metal/copper wire tractor turbine) and amount of CO2 you'll end up with an impossibly difficult calculation, at least for these comment sections.

I don't care to aim so high. I'm happy to compare $ cost farm costs & transport versus $ vertical-farm cost & electricity bill.

> energy use related to water production

Isn't that highly location dependant? Do these farm not run off the public water supply? If so, I'd assume the energy cost was higher for drinkable water.

Farmland is good for more than one crop. If the lettuce is all grown vertically, most of the farmland won't go back to "nature", it'll be used for slightly less profitable crops.

A cost worth paying, because the only alternative is billions of people starving. Whereas if vertical farms disappeared, yuppies would suffer from eating slightly less fresh lettuce but life would otherwise go on.

It's hard to imagine it is that much.

If I can buy a banana at my grocery store for 18 cents then the amount of oil/energy it took to produce that has to be less than 18 cents. Any fruit/veggie can be shipped at great distances at very marginal price cost/energy costs

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