Here are some useful graphs showing how electricty demand varies by region, month and time of day [1].
As expected, California peaks in July because there's more demand for cooling than heating. But what's a little surprising is that July is peak demand for every region.
There are many reasons why solar is so attractive as a power source, including:
1. It's the only form of power with direct electricty generation. There's no heating water to turn a turbine;
2. Solar basically has no moving parts. You can point panels towards the Sun to increase efficiency but the panel itself and transmission has no moving parts;
3. Solar panels continue to massively reduce in price and increase in efficiency and it's not clear where this ends;
4. Obviously solar generates its pwower when the Sun is shining. This conincides with when most power is usedk. Adding solar to the power generation mix reduces the peak load required to generate from other sources;
5. Solar installations can be really small, including on individual houses, reducing the transmission capacity required for last-mile and regional power transport.
Batteries are just one method to store excess power for variable (renewable) energy sources. Another is carbon sequestration to create fuel directly, called Carbon Capture and Storage ("CCS") [2]. This isn't economic yet. But it may have applications in, say, cold climates where battery performance noticeably degrades.
Solar power is the future.
[1]: https://www.eia.gov/todayinenergy/detail.php?id=42915
[2]: https://www.iisd.org/articles/deep-dive/why-carbon-capture-s...