This is my thought, looking at the graph, a good dollar per watt appears to come from getting permits and such.

I'm not aware of having to notify the local council or power company about installing solar (you do have to get certification before you can receive money for generation though, but I don't think that costs significant money, its more a case of proving provenance of solar panels and equipment. )

This is the key to this competition-winning business model: more than half the cost of a resi solar system in the US is in the installation and the design/permitting.

Permitting involves things like making sure the design is up to fire codes (eg there are setback requirements to make sure a firefighter can put a ladder on the roof) and the interconnection work with the utility that lets you send energy back into the grid. In the worst states, these extra costs are largely artificial barriers (ie outright anti-competitive tactics).

I believe Germany for example spent a lot of work streamlining these all these permitting and interconnection fees, and as a result has much lower solar costs.

What this company appeared to have proposed in this contest is that by bolting solar onto pre-fab homes in the factory:

1. Installation costs drop, presumably because it's built into the design of the home and there's factory tooling around it instead of a retrofit system; and

2. Permitting costs go down because the design is standardized and presumably you can get economies-of-scale if you're connecting a whole subdivision or trailer park all at once.

This also nicely addresses the equity angle since prefab homes are generally aimed at lower income levels -- the claim here is that this building can drop the price of solar by almost half for this demographic.

The biggest cost saving in the UK (at least) is the cost of scaffolding. its about £900 to get it up. which is 1/5th of the total install in some cases.

I have a quote to add 13kw system to my house with a flat roof for about $40k

Then I’d get 30% back from the government - and my state has no sales tax on this (which would have added 10%)

So, net cost to me of about $28k for a 13kw system

This does seem a bit pricey, but the tax rebate goes down a bit next year, so we will likely do it this year

In Australia, I think a 13kW install would be quoted at about US$10k or less. We put 5-6kW on at home, and 6-7kW at my small office building. Usually comes out to around $1/W.

Unless you live in a high cost area, sounds high to me. Quotes I have seen are below $3/watt.

* batteries not included - that’s an extra add on for about 50% more!

That should move the average cost in the US's favour - they use so much more electric in a typical home than we do. US solar installs are bigger than our average install of 3-4kW. Probably double if I had to guess.

Don't all UK installs over 6kW get counted as commercial still?

I got a quote recently (Bay Area, CA) that was about $15k for 7.7kw. So not too far off from your 9kw quote.

in Brazil I got 5kw grid-tied for about $5000. No batteries, no subsized, and have 5 years to use everything that I inject in the grid. But still have to pay a minimum of 100kwh each month just for the avalability of the grid.

American businesses optimize for wealth extraction. Prices are inflated to pay for extra homes, yachts, privatized inflated healthcare prices, etc.

Basically the emotional meme here is to wrap oneself in a reality distortion field fueled by avarice.

The way Americans rationalize this is saying that if a business is not insanely profitable, then it is not even worth starting. In tech this manifests itself as saying that you should only create "world changing" businesses, and if you have a so-called "lifestyle" business you're seen as a loser. The reality is that these insanely profitable business can only exist when you have a deep pocketed investor as a co-owner of the business, that is, a billionaire owning a large part of the business is a necessary part of the process.

I do think this is closer to the truth even though you're being downvoted. I worked in the industry for about a year and I'm working on starting up my own company now.

If you removed the 30% tax credit, it would turn $3 a watt into the UK's ~$2 a watt. I know it's not that simple but it's not far from the truth. Even Tesla is trying to launch a product at $1 watt for commercial/industry clients.