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by sci_prog 527 days ago
This is a cool concept and I love the idea but the math on the money earned from the 3276 solar panel doesn't add up. The article says the farm owner makes about $20,000 a year from the solar farm.

I'm assuming that each solar panel is 2 by 1 meter, which would mean that it produces about 400 watts (20% efficiency at 1000 watts per sq meter coming from the sun). You can use this calculator to estimate how power you can produce at the given location for a given system size in kilowatts: https://pvwatts.nrel.gov/pvwatts.php

The system above is 1310400 watts or ~1,310 kW, which according to the calculator produces about 2 million kWh/year.

If he makes $20,000 that would mean that he gets paid only $0.01 per kW of power. And even if my assumption above about the size of each individual panel is off by a factor of 2 and they are only 1 sq meter in size (which I think they are not because the article states that the solar farm can power about 300 average households, which require the annual power output to be more than what I estimated above) that would make $0.02 per kW of power. How is it possible that the amount earned per kW is so low when the utility companies in Colorado charge about $0.14 per kW (effective rate)? And who is actually the customer here and where is the money coming from? I'm just curious to learn more.

11 comments

~400W/panel @ 20% efficiency is pretty much spot on for my home rooftop solar panel specs, so your math checks out there.

$0.02/kW does seem a bit low. Looking at my bill, it looks like I got paid ~$0.03/kW last month in California where my retail price is $0.17/kW off-peak. Looking at the current price charts for electricity, they're also currently ~$0.03/kW, so the numbers do check out since we're supposed to be paid the current wholesale price.

Electricity just doesn't cost all that much to generate, most of the cost comes from transmission and storage.

Thanks for sharing this! That was the exact info I was looking for, didn't know the wholesale price was so low. But it does make sense that transmission and storage is what is inflating the retail price.
Here in Tasmania we can get between 0.08935 to 0.10 antipodean dineros per kWh for residential rooftop solar, with peak usage at around 0.35 and off-peak around the 0.17 antipodean diners per kWh. Max 10kW feed-in for residential, but you can have more installed to cover your own usage.

As far as I’m aware, commercial / industrial installations, and solar farms, get paid less per kWh.

Quick edit to fix a brain-fart, I doubt anyone read this prior anyways.

Here in BC Canada we don't get paid anything for feed-in, but we do get credit on our bill - so 1 kWh in during the day means I can use 1kWh at night without paying anything. We have 6.8kW on the roof, and it looks like over 12 months it will cover our needs.

It means I'll never have a bill, and if I get too much credit (negative bill), I'll just get a used electric car. I'm not unhappy with that situation.

It’s not entirely different here, the feed-in is applied as a credit to your account. I suppose they’d have to pay out if pushed, I’m yet to know anyone who has received actual money though. I guess I’m about to find out, if my retailer ever fixes the issue with their billing system that’s preventing any of my solar data showing correctly / at all.
> Electricity just doesn't cost all that much to generate

... from renewable resources.

Fossil energy can cost quite a bit to generate, but of course it comes with storage built in.

I have heard from a couple farmers that some venture energy corporation will pay a yearly fee to put panels on the farmland, which is probably the 20k/year he gets paid from a corporation like that. I doubt he's selling the power directly, nor was able to invest money for all those panels. He just get's a check every month. He also doesn't know the risks he's taking allowing that.

edit: I might be wrong on this, reading this on their site they have some significant donors. "With additional funding from the Walton Family Foundation, the Cielo Foundation, and donations from a myriad of individual donors and businesses in 2023"

> He also doesn't know the risks he's taking allowing that.

I don't know either; what are the risks?

I think the 20k number is something of a throw-away, and not really explained.

For example, is that 20k gross revenue (check from utility) or net revenue (after deducting financing costs?) Is he getting free grid power at night as well? Is he using power on the farm itself?

It's a pity the article didn't go down this road a bit, but since it didn't, I guess the 20k number (described as an "estimate") is really just a measure of scale.

Indeed, one gets the impression that the finances part is possibly not the main focus of the farmer (much less the article.) The farming land is being used by non-profits and research groups, he's not actually farming the land himself.

But it sounds like this is just a small part of his farm (4 acres), so perhaps more of a pilot project and finding out how to best use the land, before rolling out on a bigger scale.

It's a business they would be depreciating the cost of panels. He is probably making $20k profit
I took $20k to be profit after costs (except maybe personal labor and land), not revenue.
> If he makes $20,000 that would mean that he gets paid only $0.01 per kW of power. And even if my assumption above about the size of each

As others have mentioned the off peak daytime wholesale rate for electricity is often just a few cents per kWh. Let's say 3-4c/kWh.

The other few cents above your calculated rate of 1c/kWh likely go to pay off the principle and interest on the financing for the system, plus any profit for the company maintaining and servicing the system. If the farm owner paid for the capital costs and maintenance directly themselves, their share of the returns would probably be higher.

But they would probably prefer to focus on farming crops.

Is there anything about farming that makes financial sense?

Most farmers (even in developed countries) are cash poor and most farmers are deep in debt.

The ones that aren’t can quickly become so given a little bad luck. Farms have to hedge against bad yields to protect against undesirable weather.

Family farms only make financial sense if there is a lot of free labor (slavery, indentured servants, or unpaid labor of children).

That isn't an issue with farming. It's the competitive pressures of the electricity market in the US. Most of the US is currently powered by natural gas, which is about five times less expensive in the US than in Europe. Colorado is a bit different, they still have 33% from coal (US wide coal is 16%). The quick and easy solution would be for electricity to be more like the rest of the world and more expensive. Europe will actually be much worse soon due to a price cap is expiring at the end of this month.
Or if they can act as a quasi-shell corporation for an agribusiness concern to cash in on tax breaks. And at that point, if the family makes any money at all, the parent corp will surely find a way to harvest that too.
There was a link here a few weeks ago about UK energy that said that only about 30% of the cost of energy is the cost to produce, the rest is the infrastructure and the costs to pay some suppliers to stay online in case they are needed.
I guess the transmission lines themselves is where the costs are
When it's very sunny and your solar panels produce a lot there are many other solar panels also producing a lot, so electricity is generally cheap.
(There’s a typo in your profile)