@vogon This looks way more complicated/expensive than hydro, or even batteries. Round-trip losses and cost per stored kWh have to be low enough for it to be viable. On the other hand, every extra meter of crane gives great dividends

For fun, some quick calculation assuming you have that 120 meter crane (60 meter average height): concrete density = 2400 kg/m³, concrete cost = $108 per yd³ ($141 / m³). E = 2400*9.82*60 = 0.4 kWh. You're looking at $350 per kWh energy stored, compared to around $50 for lead-acid (alibaba). Even if you fill used oil drums ($8 per 208 liter drum) with dirt, you're still looking at $100 per kWh

I'm more psyched about some of the carbon technology that's coming out, where we can make batteries for bulk storage out of say used car tires or wood waste. Potentially way cheaper than lead-acid. Non-toxic too