So they could build a battery big enough to serve 15 minutes of the nighttime trough and declare mission accomplished with only enough solar to fill the battery

So they could build a battery big enough to serve 15 minutes of the nighttime trough and declare mission accomplished with only enough solar to fill the battery on a rainy winter solstice day? Some goalposts just beg for getting moved. (I assume that this is unrelated to the 2045 goal, so it's not really bad, just bad headlining)