> Where are you planning on getting the elevation delta from?

Elevation delta is not hard to find in Norway! A typical pumped storage facility uses 100m of delta; I imagine Norwegian ones would use more.

> but this is a field where capex + opex/KWH is everything.

And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.

The original post is efficient for heat storage, but converting low grade heat to electricity is not efficient.

For some applications, you don't actually convert the heat to electricity.

This sounds pretty cheap if it works out:

https://austinvernon.site/blog/standardthermal.html

> A typical pumped storage facility uses 100m of delta

Most projects seek 200-600m. This map doesn't even consider pumped hydro <200m: https://maps.nrel.gov/psh

> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.

Based on what? Cost is particularly variable for pumped hydro. It can be one of the cheaper options when stars align. But you need 1) a suitable geography that minimizes the cost of damming or digging a resivoir with sufficient head 2) available for development without too much backlash 3) Near enough grid resources to minimize infrastructure and line losses. I'm surely leaving pieces out.

It can be cheap, but it has far more hoops to jump than alternatives like batteries, hot sand and other "storage-in-a-building" designs which can be built where needed and using fairly standard industrial construction.