&gt; Cost comparisons with pumped hydro are difficult, he said, because there are so few projects and not many data points.<p>There are 36 in Germany alone[1].<p><a href="https:&#x2F;&#x2F;de.wikipedia.org&#x2F;wiki&#x2F;Liste_von_Pumpspeicherkraftwerken" rel="nofollow">https:&#x2F;&#x2F;de.wikipedia.org&#x2F;wiki&#x2F;Liste_von_Pumpspeicherkraftwer...</a> (the corresponding English article lists much less)