
Underground Pumped Hydroelectric Storage: A Feasibility Study - syllable_studio
https://blog.syllablehq.com/underground-pumped-hydroelectric-storage-a-feasibility-study/
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sfink
How hard is it to pump water out of a tank that's a mile underwater? How does
one do that?

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syllable_studio
Hi @sfink,

Thanks for asking. It's likely that the optimal design for a head height of a
mile would use two stages. You would have an intermediate reservoir half a
mile down. Reversible, Francis-type pump-turbines would likely be used.
[https://en.wikipedia.org/wiki/Francis_turbine](https://en.wikipedia.org/wiki/Francis_turbine)

From my paper: " 8.1 PEPC Study: Two-Step Design with Reversible Pump-turbines
The PEPC study’s optimized design called for single-stage reversible pump-
turbines with identical layout and design. Each step consisted of three pump-
turbine/motor-generator sets, each of 333-MW rating and each operating at 720
rpm under a nominal head of 762 m (2500 ft). With two steps combined, the
overall nominal head was 1525 m (5000 ft). The study acknowledges that future
technological development could significantly raise the head height or achieve
the same head height in only one step. "

Or here is the original source for that info. Underground pumped hydroelectric
storage Allen, R.D., Doherty, T.J., and Kannberg, L.D., for the Pacific
Northwest Laboratory, sponsored by the United States DOE
[https://www.osti.gov/biblio/6517343](https://www.osti.gov/biblio/6517343)

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syllable_studio
Author here,

Here is a TLDR Summary of the Report. [https://github.com/syllable-hq/uphs-
feasibility-study/blob/m...](https://github.com/syllable-hq/uphs-feasibility-
study/blob/master/resources/underground-pumped-hydroelectric-storage-
feasibility-study-summary.pdf)

Thanks for any feedback, corrections, or suggestions.

Cheers, Eric

