The book was written in 2021 and solar has grown dramatically since then. I think synthetic fuels created using solar power will be a big part of the energy mix going forward. There are companies like Terraform Industries
https://www.terraformindustries.com/ and Prometheus Fuels https://prometheusfuels.com/ (these are not an endorsements) which are pushing in this direction. If synthetic fuels take off, then there would be massive demand for more solar.
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I also think that solar power will also be used in food production. It will be needed for creating fertilizer. And more directly it can be used to create food from air and water using hydrogen oxidizing bacteria. Solar Foods is an example of a company doing this https://solarfoods.com/ (again not endorsing them). If this kind of food production becomes widespread, it will require a lot of solar panels.
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