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by booli 1023 days ago
I think with new(er) GaN(or SiC) DC/DC buck conversion, 380V systems can get up to 98.2%, typically around 94% efficiency now.

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.
2 comments
tomas789 1023 days ago
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.

[1] https://www.velocitymicro.com/blog/what-is-psu-efficiency-an...

[2] https://www.electricaleasy.com/2014/04/transformer-losses-an....

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algo_trader 1023 days ago
Yes. The original commenter is a bit behind the times. There is also reliability advantages.

> 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

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tomas789 1023 days ago
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]

[1] https://www.nrel.gov/docs/fy22osti/83586.pdf

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algo_trader 1023 days ago
> but this is actually my day job.

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.

[1] https://news.ycombinator.com/item?id=37260441

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