Sure, my calculations assumed about 48 hours of storage. But there's a pretty big difference between 48 hours and seasonal storage where you need weeks (400 hours).
What Tesla is currently doing is installing about 4 hours of battery for the typical site, so about two orders of magnitude away from being able to scavenge all that wasted power on a fully PV grid, but fairly optimal to ensure full use of stored power.
It is key to understand the seasonal variation of sunlight. This is a much worse problem at high latitudes. But at lower latitudes (say, anything less than 45-50 degrees, i.e. >80% of the world's population), PV is now cheap enough it's cheaper to just over-size the PV array to provide power even when it's cloudy and/or winter than to provide weeks or months of storage.
EDIT: Maybe "wasted" is the wrong word. Is your car engine "wasted" just because it's not red-lining 24/7? Averaged over a year, your engine only has a "capacity factor" of about 0.2%, but the energy is there when you need it, and it's still affordable. Likewise with solar, it's okay if not all the electricity is utilized, as long as it produces enough on cloudier days to not require a ton of storage (up to ~50 hours of storage is fine).
What Tesla is currently doing is installing about 4 hours of battery for the typical site, so about two orders of magnitude away from being able to scavenge all that wasted power on a fully PV grid, but fairly optimal to ensure full use of stored power.
It is key to understand the seasonal variation of sunlight. This is a much worse problem at high latitudes. But at lower latitudes (say, anything less than 45-50 degrees, i.e. >80% of the world's population), PV is now cheap enough it's cheaper to just over-size the PV array to provide power even when it's cloudy and/or winter than to provide weeks or months of storage.
EDIT: Maybe "wasted" is the wrong word. Is your car engine "wasted" just because it's not red-lining 24/7? Averaged over a year, your engine only has a "capacity factor" of about 0.2%, but the energy is there when you need it, and it's still affordable. Likewise with solar, it's okay if not all the electricity is utilized, as long as it produces enough on cloudier days to not require a ton of storage (up to ~50 hours of storage is fine).