I'll note that aggregate system cost still benefits significantly from including wind and other non-solar sources of energy; having a mix of different intermittent sources (and some firm generation such as geothermal) means less storage is needed.
There was this guy that made a pumped hydro water tank on his roof and by his calculations a cubic meter of water was equivalent to a AA battery.
That sounds crazy. Let's do some math. From what I can find, a double A battery contains about 10-14 kilojoules of energy. Let's use 14 to be charitable.
A cubic meter of water weighs about 1000kg. We know the formula for potential gravitational energy U = mgh. So if we used all the energy from the battery, we could lift the water:
That sounds crazy. Let's do some math. From what I can find, a double A battery contains about 10-14 kilojoules of energy. Let's use 14 to be charitable.
A cubic meter of water weighs about 1000kg. We know the formula for potential gravitational energy U = mgh. So if we used all the energy from the battery, we could lift the water:
That assumes 100% efficiency of course. Still, lifting a ton of water even two feet ain't nothing to sneeze at. Batteries have a lot of energy.
Thank you for doing the math! I think this was the video of the fella doing his water tank battery: https://youtu.be/CMR9z9Xr8GM?si=go28fQ6DYXyW1GTi