That just isn’t true. Solar is among the cheapest per watt to build [0] and produces very cheap electricity [1] even if you remove subsidies. It isn’t a perfect technology but that is beside the point. Further, every other technology for producing electricity has subsidies: wind (similar tax benes), nuclear (the gov acts as the insurer of last resort in a catastrophe, unpriced externality of waste heat), coal (unpriced externalities for carbon, soot, heavy metals, waste heat), natural gas (unpriced externalities for carbon, waste heat for combined cycle), hydro has all sorts of hard to price externalities and they are usually built with the help of the government (financing, dislocating people, rights of way, building new shipping lanes, etc).
Well that sure is interesting, it's the exact opposite of what I've read before. Having not read that entire novel, I do have to ask if that's taking the average yearly Wh of a solar panel or what it says on the tin? Because it'll only produce that in Mexico during summer at midday. These costs can't be fixed but likely vary significantly by latitude and weather type.
Anyhow if that's somehow correct and the price is $29.04 for a solar MWh and $121.84 for battery storage, then taking night into account for a 1MW installation you need 2x the solar capacity to make up the night draw during the day and a 12 MWh battery bank, so in total that would be $58.08 for the panels and $1462.08 for storage. Not exactly feasible by itself still. That's simplified of course, as you don't get as much draw at night, but you also have to consider that in winter you'll basically get nothing from the panels, so you may need even more than just 2x.
[0] https://www.eia.gov/outlooks/aeo/assumptions/pdf/table_8.2.p...
[1] https://www.eia.gov/outlooks/aeo/pdf/electricity_generation....