It's the regulation cost that's really hurting us.
Just the required paperwork for the permit in my region cost ~2.5k. structural engineer was 800, architecture diagram was 800, certified electrician stamp on the plans was 800.
Add in the extra cost to facilitate RSD (~5k after mlpe devices, and extra wiring) and tack on the cost for utility interconnection agreements.
Then deal with the NEC requiring UL listed items with no/very little cross certification with things like CE which effectively means you can't buy equipment from China, at least not without a US shop taking a huge markup for branding/certs.
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Overall, it's just a mess. I walked away from the project (completed, all approved) with a huge dose of skepticism for the permitting/certification/approval process.
11.2kw in panels, ~12kwh lfp battery, split phase 240v install - ~28k usd.
Of which ~10k was regulation driven, and doesn't change much by install size.