Photovoltaic cells are even less efficient, I think they’re somewhere between 10-20% efficient. I think the way to go would be a solar collector, like the Archimedes death ray, but much much bigger.
The fantastic thing about renewables is how much they lend themselves to a less centralised model. Solar collector? Sure, why not‽ Rooftop solar on people’s houses? You bet! Geothermal? If local conditions are favourable to it, absolutely!
Instead of a small number of massive power plants that only governments or really large corporations can operate individuals can generate the power for themselves, or companies can offset their costs by generating a little power, or cities can operate a smaller plant to power what operations in their city aren’t handled by other means. It’s not a one-size-fits-all approach.
This contrasts with nuclear. SMRs could theoretically do the same thing, but haven’t yet proven viable. And traditional plants just put out way too much power. They’re one-size-fits-all by definition, and only have the ability to operate alongside other modes with the other modes filling in a small amount around the edges.
That is already a thing and it’s called concentrated solar power. Basically aim a shit load of mirrors at a target to heat it, run some working fluid through the target and use that to make steam to turn a turbine. There are a few power plants that use it but in general it has been more finicky and disruptive to the local environment than traditional PV panels would be.
