Nothing new !!
Has been done in Germany since 1908..... In 1907, the Heidenheim-based entrepreneur and engineer, Friedrich Voith, purchased the Brunnenmühle, a water mill close to his factory and established a research institute for hydro turbines there. The mill lies in a valley on the River Brenz...
In order to achieve the required drop height for his turbine experiments, Voith constructed an uphill water storage tank in neighboring Schlossberg. From there, the water rushed through pipes into the Brunnenmühle. If the tank was empty, water was pumped up from the bottom again. Through this research institute at the water mill, Voith almost inadvertently constructed Germany's first pumped storage plant. It was commissioned on 14 November 1908.
The Brunnenmühle is still used as Voith Hydro's research and development center. It was fully modernized in 2008.
I was there ( Heidenheim) in 1980... Its also the birthplace of Rommel ( Desert Fox )
http://voith.com/corp-en/industry-solutions/hydropower/pumped-storage-plants.html
