(Disclaimer: I know nothing about farming)
I somewhat agree - dumping pesticides and fertilizer into the ground every year and then letting it pollute rivers is low-key insanity. But then you look at just how much farmland is out there and realize some crops just can't be put indoors, probably ever.
There are lots of variables for sure, but I do wonder how much more efficient indoor growing must get to overcome outdoor growing? Land value is vastly different between regions, so does labour, crop type, etc.
p.s. Tom Scotts recent video on strawberries was amazing - special mites to fend off other bugs and UVC light sanitizing was a bit of wow for me.
Ag runoff is certainly a thing.
But also, if you harvest a crop, those are elements that are leaving the field and need to be replenished. Annual fertilization will always be a thing for any crop or combination of crops, if only for micronutrients.
They aren’t talking about growing wheat indoors, and when they talk about tunnels it’s a bed crop in a field with plastic over it like you’d see over a box in the city.
Indoor growing has some cool stuff going for it, but you’re not going to grow row crops that we currently harvest headers wider than your greenhouse.
You’re also unlikely to put those under solar, if you’re going to do solar on that patch, it’s probably not worth farming a crop that produces 1000$ per acre under it when the solar is going to be producing way more than that.
My area averages about 175 bushels/acre for trash soil and closes in on 250/acre for prime River bottoms.
$1125 an acre without expenses is what you can expect in a GREAT year. But that's every year and it's insured against crop failure. The last years that we farmed, about 70% of our gross went to expenses. So figure about $450/acre in profit (mostly to pay for my house and food and what not).
Can electricity compete with that? I genuinely do not know.
An "acre" is about 4047m² in modern units, so at "one sun" of 1000W/m² you would get 4.047 megawatts per acre. Multiply by the factors above, you actually 89kW/acre. A year is 8766 hours, so that's 780MWh/acre/year.
Suppose you get a PPA signed for 3 cents a kilowatt hour, US$30/MWh. That's US$23400/acre/year. But that's revenue, not profit. You can compare it to the US$1125/acre/year you give above. So what are the expenses?
The most fundamental cost here is the solar modules. 4.047MW at 50% coverage and 22% efficiency is still 445kW peak. At the current US$0.15/Wp in international markets, that's US$67000 to plant that field with panels, noticeably more than the US$675 you report to plant it with corn.
But, if you're still measuring land in acres, as if we were in the Canterbury Tales, you're probably in the US, where modules cost roughly double what they cost in the rest of the world, due to bipartisan tariffs to protect US fossil fuel interests. And the balance-of-plant costs are typically about double the cost of the modules alone. So, instead of US$67000, you're probably looking at US$300k for those 445kW (or 597 horsepower, or the power of roughly 1100 American-football running backs, if you're more comfortable with those units.)
US$23k per year from a US$300k investment is about 7% ROI, which is probably profitable but not wildly so. And if you don't have a signed PPA, you can expect that revenue to decline, as cheaper panels and power electronics drive the value of daytime generation to zero, and household units that don't need such high balance-of-plant costs reduce demand for utility-scale generation. Also, you can expect heavy industry to move to countries where solar power costs less, reducing demand.
The cost of the land isn't really significant at these investment levels.
Your costs are also wildly off. Panels are like 25% of cost. Rest is inverters, mounting, labour and most significant - connection to grid.
Here's the fun thing: if humanity were one united species instead of a bunch of tribes willing to fuck each other up every few decades, we might just go and grow crops where they grow the best, maybe with a bit of redundancy to guard against natural disasters and whatnot.
But unfortunately we are not, and so we have massive overproduction going on, which in turn means without insane amounts of subsidies (25% of the EU budget goes to farm subsidies!) farms could not survive.
If the subsidies were killed, even shit solar panels would yield more money than a lot of land could yield with growing crops.
For few years, then every solar farm would go bankrupt all while food supplies gone.
TBF New Zealand is one of the few countries that removes subsidies from farmers - it was terrible for few decades, but eventually turned out to be great.