Comment by bryanlarsen
21 hours ago
> 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.
> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.
This is incorrect. There is currently not a single pumped hydro station that is suitable for seasonal storage. They're all designed to drain their upper reservoir in 4-16 hours.
It's the only thing that's half economical. Do the math: Even a modest power plant - 1 GW output - that can run for 1000 hours means you need a 1 TWh (even typing it feels ridiculous) storage reservoir. If you only have 100m of head, that's 3 cubic kilometers of water. That would mean building an artificial lake that immediately would be Norway's 6th largest body of fresh water, and draining it completely every winter.
And effectively, you'd have to build it twice - you also need a lower reservoir. Because there's nowhere to get 3 cubic kilometers of fresh water to fill it otherwise, and you really don't want to do pumped hydro with seawater.
And yet it's still far cheaper than any other form of seasonal storage.
Seasonal storage is crazy expensive. You need a lot of power, and a lot of energy, but you can only amortize the cost over one or two usages per year.
Norway already have seasonal storage with a storage capacity equivalent to 6-8 months of total electricity use in the form of its existing hydroelectric plants, with no need to pump things back up again.
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.