AFAIK PC power supplies are actually one of the most efficient power supplies out there so I'll use them as a reference. The Titanium class of power supplies is around 94% efficient at 100% load and 90% at 20% load [1]. On the other hand plain old transformers start at around 95% and can go even higher. Random internet source claims that it can be 98.5% efficient [2].
Of course you cannot run your computer at AC. I had mostly grid-scale equipment in mind. I just wanted to use something relatable as an example.
Original commenter might be a bit behind on many things but this is actually my day job.
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.
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.