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Comment by vkou | Hacker News Reader

It's popular and growing because of credits and subsidies. Remove all credits and subsidies, and I can build utility-scale solar for less than half the cost per KWH than you can install panels on your roof.

There's way too much human labour involved in getting someone to drive to your house, climb onto your roof and bolt panels to it. In that time, that same worker could set up a dozen similarly-sized panels when building out a utility solar farm.

And yes, if your time is worthless, and you don't value your neck, you could DIY, and save on some of those costs.

... But you'd still be tied to the grid (and paying grid fees), unless you are ready to invest $XY,000 for a massive battery bank... That might still leave you without electricity during a period of low generation/high consumption.

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> There's way too much human labour involved in getting someone to drive to your house, climb onto your roof and bolt panels to it. In that time, that same worker could set up a dozen similarly-sized panels when building out a utility solar farm.

At some point I'm going to pay someone to come out re-shingle my roof anyway.

Sure, but even shitty tar paper roofs last 20 years. Stone and metal roofs can last much longer.

>And yes, if your time is worthless, and you don't value your neck, you could DIY, and save on some of those costs.

This is such a cop out. How I spend my time is up to me. If it's a DIY weekend project being worked on a weekend that I had no other plans, then it's not really a cost to me. Sure, professionally, I have my hourly rate that determines my "worth". However, I do not get to bill those hours 24/7/365. Even playing along with your premise, if I'm playing weekend electrician, I'm not a master electrician making the same rates as my other job so a 1:1 correlation is just a lame argument.

How you spend your time is fine. Most people lack the expertise to maintain a solar panel. This becomes an issue when you die or sell your house and the new owners don't know anything about maintaining solar roofing. Over time, this will become a massive cost center especially since solar panel installation have a painful lack of standardization, especially DIY panels, which drives up costs immensely.

>This becomes an issue when you die or sell your house and the new owners don't know anything about maintaining solar roofing

I'm setting aside the "when you die" part, but acknowleding its presence.

However, the new owners get a small tear and a tune from the world's tiniest violin. They know the panels are there when they buy the house. It's not a surprise at closing. If they decide to buy the house with that knowledge, then that's on them, their realtor, their inspector, etc. It's like saying someone that buys a full size truck and complains they didn't know the expense of fuel.

Where do you put the solar farm?

Unproductive farm fields.

Literally anywhere that's not prime real estate. There's three orders of magnitude more of that kind of surface area on this planet than there are single-family home roofs. [1] I think we can figure something out.

[1] 2 billion 'single-family' homes, 800 square feet of roof/average [2], ~50,000 square miles of roof space. Total land area of the Earth is 57 million square miles. You can take your pick of which 50,000 of it can be used for utility solar...

[2] This is a large over-estimate, reality is much smaller than that.

If you take Europe as an example, every area that is not "prime real estate" is either agriculture or protected forests. Transport of electricity over very long distances is not easy, see https://www.pv-magazine.com/2021/05/18/geopolitical-impact-o... for a few of the challenges.

The interesting question is what happens if battery prices continue to decline so that $XY,000 becomes $X000 and thereby less than grid fees.

Low generation can be solved with an inexpensive gas generator for use in emergencies the likes of which might see three days use in a year.

If battery fees get lower than peaker plant-related grid fees, then grids will shut down peaker plants and instead buy warehouses full of batteries.

Aren't some significant fraction of grid fees the grid itself? The land, paying linemen to repair storm damage, the administrative apparatus to negotiate with everyone and collect payments.

You still need all of that if you put all the batteries together in a warehouse, not if you put them in each person's basement.

Those costs are still significant lower than building XY square feet of basement, that you now can't use for anything, because its space is physically occupied by electric infrastructure.

Again, economies of scale.

Don't you still need the same amount of space at the warehouse?

Tesla Powerwall 2 appears to be <5 cubic feet. That doesn't seem like a lot.

I don't think the grid can ever go away. Regional solar is just too variable. You might get backup for a day, but storage costs scale linearly with duration.

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