Pumped storage is an environmentally friendly method for electricity storage that generates minimal CO2 emissions compared to alternative storage solutions. This paper focuses on the current state-of-the-art pumped storage penstocks, which serve as conduits for high-pressure liquid flow between vertical reservoirs. Examining the dynamic response of these penstocks reveals that the water hammer induced by the turbine inlet valve's (TIV) closure increases the equivalent stress on the penstock material. Notably, the water hammer effect is negligible in low head pumped storage scenarios. This study confirmed that utilizing seawater yields minimal disparities in the dynamic pressure response of the penstock element. Furthermore, the Mach number and velocity distribution exhibit no significant differences in the context of low-head pumps.