A study was recently undertaken to determine the role and value of advanced pumped-storage hydropower (PSH) in the U.S.1 Work involved developing detailed simulation models of advanced PSH technologies (adjustable speed, or AS, and ternary units) in order to analyze their technical capabilities to provide grid services and to assess the value of these services under different market structures and for different levels of renewable generation resources integrated in the power system.
Compared with fixed-speed (FS) PSH units, AS and ternary units provide greater operating flexibility and efficiency but are more expensive to build due to additional equipment and space requirements. An especially important characteristic of AS and ternary technology is their ability to provide regulation service in the pumping mode of operation…