In the US at least, transmission loss seems to be on order of 5% of total energy distributed. Source: https://www.eia.gov/tools/faqs/faq.php?id=105&t=3#:~:text=Th....

The economies of scale seem to be much larger. For example, utility scale solar seems to be about half the unit cost compared to residential and commercial solar: https://www.nrel.gov/analysis/solar-installed-system-cost.ht...