Balcony solar is even cheaper to build than utility-scale solar.

It's limited to 800W in Germany and 1200W in Utah. It isn't about to replace utility-scale generation anytime soon.

Those limits are just arbitrary regulations. It's easy to install 10x that on a residential roof.

And we come back to my original point. Residential roof installation is the most expensive way to install solar power. Utility scale solar is easily haf the cost of residential.

> Utility scale solar is easily half the cost of residential.

If it's only half, the problem it's not going to stop residential installs. By the time that utility power gets to them here in Australia it costs about 3 times as much, so they are going to install their rooftop systems anyway.

I can't speak for elsewhere, but here in Australia residential installs tend to be over provisioned. A small'ish install is 5kW. That generates about 20kWh per day. Typical household consumption is 1/2 that. Newer builds like mine tend to have far more - upwards of 20kW of panels. That's to cater for charging EV's. The result is grid solar installs are getting hammered by roof top solar: https://reneweconomy.com.au/wind-and-solar-hit-record-share-...

In the US it's typically about a quarter.

It shouldn't be that expensive. I had 10x 500w installed and wired on my 7-8 meter high roof in 1/2 day.

I only paid $50 where I ljve, but even with 10x higher labor costs in the US, it should be under $1000.

It shouldn't be, I agree. And eventually it won't be. But SEIA's report https://www.seia.org/research-resources/solar-market-insight... said that, in Q1 of 02024, utility-scale fixed-tilt installations in the USA averaged 98¢ per peak watt, of which 40¢ was the PV modules; and residential installations averaged 325¢ per peak watt, of which 20¢ was the PV modules, which is an atypically low share, historically speaking.

Where do you live?

I'm surprised at the 40¢ figure for utility scale. Are you sure that didn't include the mounting hardware? Utility-scale PV is typically with 1-axis trackers.

Another possibility would be that utility scale solar optimizes to a much large disparity between DC rating and AC rating than does domestic rooftop PV.

I was surprised at it too, but remember that the US basically doesn't allow Chinese solar panels to be imported.

Wait, so those were not US residential cost figures you quoted? Because I don't see how they'd allow Chinese imports for only residential installation.

Those were also US, yes. I don't know why they were so much cheaper. Possibilities include:

- Maybe the SEIA is wrong.

- Maybe utility-scale projects sign contracts to buy PV modules further in advance. The prices were falling rapidly.

- Maybe residential installers were buying low-cost panels with lower efficiency or with no warranty.

Balcony solar is installed on a unit-by-unit basis. It isn't 800W per building; it's potentially up to 800W for each unit in an apartment.

That's still not a lot. Less than a hairdryer uses.

A heavily used hairdryer is typically in use for 5 minutes per day, so a 1500-watt-peak hairdryer might average 5.2 watts. It needs 1500 watts of batteries (say, 3kWh of 0.5C batteries, or 0.4kWh of 4C batteries), not 1500 watts of solar panels.

That only applies if you connect it to the grid in each of those places, I believe.

I can't wrap my head around what off-grid balcony solar even means. Balcony solar is meant for apartment dwellers. Or detached home/townhome owners who don't want to spend on a rooftop install. You aren't installing balcony solar to go fully off-grid.

Sure, but you don't need to go fully off-grid to have an off-grid balcony solar panel. You can connect it to just your freezer, or just a storage heater, or to the batteries you run your homelab off of.

Balcony solar can still satisfy a significant portion of a household's demand.

Utility-scale solar needs land and has to deal with line losses. Rooftop solar does not have to deal with either.

Utility scale is 2x cheaper despite all that.

> Utility scale is 2x cheaper despite all that.

I think you mean cheaper for the utility. It is certainly not cheaper for me, the homeowner.

The only reason for that is that you still have access to the grid and are gaming the system via a rate structure that allows you to free ride.

Not necessarily - you have to pay for that infrastructure between the plant and your home.