Re: The Physics Behind the Spanish Blackout

On Fri, 13 Jun 2025 01:03:01 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:

On 6/12/2025 6:36 PM, KevinJ93 wrote:

 >> I calculated the cost of the wear and tear on the battery is (very)
 >> approximately $0.25/kWh.
 >
 > So, if you have a surplus, it makes sense to make it available (even though
 > whether or not you have a buyer may be uncertain on any given day)
 >
 >>  > What sort of capacity do you have and how easily do you "top it off"
 >>  > purely from solar?
 >>
 >> I only have 27kWh of storage (2 Tesla Powerwall units). In the summer
 >> I average 20-35kWh per day of surplus generated by solar. So if the
 >> battery has discharged to 25% (own use plus any exported) in the
 >> evening it can be fully recharged the next day.
 >
 > We use about 25KWHr/day (it's not "hot" yet).  So, would need to generate
 > about 50KWHr daily to meet that sort of storage ability.  Without
 > resorting to
 > a tracking collector, I think we're limited to about 6.5 usable solar hours
 > daily.  So, would need ~8KW from an array to "bank" that much.
 
Our usage is very similar (somewhat higher in peak summer - last July 4th we
consumed ~70kWH).

>
Our daily *average* will approach that (about 65KWHr) once it gets hot.
Or humid.  (Or both).  So, 50KWHr won't even meet our daily needs
(assuming we could bank it without having to take a loss using
the grid as that bank)

We leave the gas heat on all year... never touch the thermostat.

Most all the world wants a/c, and wants to keep the windows closed and
the mosquitoes out. Air conditioning 9 billion people is going to take
a lot of power.