4 ms·

This is a solved problem: https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/ https://qz.com/1355672/stacking-concr

• Godel_unicode 8y ago
  We use the word "solved" differently.
• ben_w 8y ago
  “A 120-meter (nearly 400-foot) tall, six-armed crane stands in the middle. In the discharged state, concrete cylinders weighing 35 metric tons each…” 120 m * 35,000 kg * 9.8 m/s/s = 41.2 MJ = 11.4 kWh. LiIon: 250–693 W·h/L, 100–265 W·h/kg, 250~300 USD/kWh in 2018 -> 11.4 kWh = 45.7-16.5 litres, 114-43 kg, $2850-$3420. Concrete is much harder for me to find number for, seems to be $92/cubic yard, 2.4 tons/cubic meter. 35 tons -> 14.5 cubic meters -> ~19 cubic yards -> $1748 plus whatever the cost of a crane that can lift 35 tons is. My knowledge of cranes is whatever came up first on Google: “””A Comadil CTT 361-20 is a good size crane able to do concrete panels, max jib length is 75 meters and they have a max lift capacity of 20 tonnes. These cranes can go up pretty high without needing to be tied into the building. This crane will cost around $1 million””” Article later talks about renting smaller 4-5 ton capacity cranes for $1500-$2000 per week. The problem is neither LiIon nor concrete with cranes nor hydrogen are cheap enough. Not yet.