Comments by "Titanium Rain" (@ChucksSEADnDEAD) on "Energy Vault: MEGA-BUSTED!" video.

@Graknorke A dam can support several times its mass equivalent in water. So the dam always wins when compared to using blocks.
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The concept is sound because the proposal is energy storage, aka doing something with the energy you're getting "for free" out of intermittent renewable but may need later. Obviously losses are undesirable, but the alternatives are either unplugging those generators or paying a neighboring country to take it (California has paid Arizona to take their excess energy), then you'll need to pay to import energy or fire up gas plants while your renewables are down. While reducing losses are a big deal, high capacity, low construction and operational costs are much more important. If it costs 50 billion for a 99% efficient battery bank which can store a week's worth of energy, and 1 billion to build a dam that's 60% efficient but can handle a month's worth of energy.... at that point the 40% losses are kind of meaningless because the alternative is 100% loss without storage. In reality the pumped water dam can be 70-85% efficient so it's not even that bad.
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