[londons_explore]

For new installation, yes, for any size a switched mode supply will usually be better in all dimensions. For the largest sizes, you can't buy them off the shelf, and there design costs may dominate. But after the thing is designed, in component costs, switched mode will win. Everything scales linearly with kVA, so there is no economics crossover point for the fundamental materials.

Eventually it will be worth switching out old transformers - they contain a massive amount of valuable copper and quite valuable steel, and their lower efficiency means every year they remain in service they are wasting $$$'s of electricity.

Transformers in cities can often be replaced with much smaller switched mode units underground, allowing the building housing the old transformer to be rebuilt as luxury flats to make the project much more profitable too!

[snowwindwaves]

Large power transformers have efficiencies in the 98-99.75% range.

I don't doubt switch mode could be smaller and cheaper up to some size, but I am struggling to see transformers larger than about 5 mva being replaced with power electronics.

Solar farms etc have inverters in modules I believe 500 kva each - and of course the power electronics are necessary there, there is no substitute.

I have a 20 MVA transformer that is nearly at end of life and would be open to cheaper replacements.

[mschuster91]

> but I am struggling to see transformers larger than about 5 mva being replaced with power electronics.

We already see these at the substations at each end of a HVDC link, China is operating well over a dozen of them with capacities of up to 12 GW (https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity...).

[hwillis]

For 5-20 MVA you're talking about 67 kV substations or similar, where a transformer costs in the low 6 figures. HVDC converter stations in the same range would cost somewhere around 8 figures, although that's mostly a guess- you typically need maintenance and supervision in a way that you don't with transformers. 1%+ downtime is pretty common, which absolutely sucks if you aren't a full grid and can't pull extra generation.

[mschuster91]

Yeah, but that price tag is mostly due to the fact that HVDC isn't a widespread technology yet. Once factors of scale come into play, the situation will look different and the prices come down.

Additionally, the price of copper is already at an/near the all-time high and it's not going to get cheaper, and the land on which huge transformers sit is shooting up in value... so in the end, market forces may push towards solid-state technology anyway.