Edit: And voltage of these type of DC grids are often higher (600V - 1000V, or industrial even up to 1500V), so losses in cables are less.
[1] https://www.velocitymicro.com/blog/what-is-psu-efficiency-an...
[2] https://www.electricaleasy.com/2014/04/transformer-losses-an....
> new(er) GaN(or SiC) DC/DC buck conversion
Can you share guide lines about costs?
For comparison, utility scale AC inverters for PV are ~$5-$10/kW
Do you have a source for the reliability claim? There are so many good old transformers deployed around the world. Many of them working for 10s of years without a replacement. I'd be suspicious that a buck converter will have longer MTBF than oil submerged transformer.
Also, I don't see why it is mentioned here but NREL estimates the cost of grid scale inverters (for installations of 100 MW) to be 5-10x more than what was mentioned. [1]
You are probably more knowledgable than me. I am just here for the cake.
However, AFAIK the most fault prone components in PV are inverters and (where applicable) transformers.
> 5-10x more than what was mentioned.
This was my mistake. I started with 5c/W and missed a decimal place.
None of this addresses the key issue - you mentioned 10% loss for a simple DC converter, and the next commenter [1] mentioned the newer generation of far superior alternatives.