I'm going to suggest you think through what I've written, the general problem of power grids, generation, and storage, energy uses, and consequences of power outages. The answer may reveal itself to you.
Likewise, you seem to have failed to grasp what I'd hoped would be a rather evident reason for mentioning the Netherlands in the context of pumped hydro and terrain.
Likewise, you seem to have failed to grasp what I'd hoped would be a rather evident reason for mentioning the Netherlands in the context of pumped hydro and terrain.