Photovoltaics with Battery Storage Cheaper than Conventional Power Plants
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.
How does solar + pumped hydro compare? I thought I read somewhere the cost of pumped hydro per unit of storage was crazy cheap (assuming suitable enough sites are available). I think that kind of system probably makes a whole lot of sense too for places where the geography allows.
Pumped hydro is great for taking advantage of the geography but it's thousands of times less energy dense. 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. A professional damm might be a bit more efficient though.
I'm looking forward to see more heat based storage, like molten salt, heated sand, or pumped geothermal.
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: