CSP vs. PV

Concentrated solar power can store energy as molten salt and dispatch electricity after sunset. Solar PV cannot do this without batteries. Yet PV has captured 99% of the solar market. The reason is cost: PV's learning curve crushed CSP's dispatchability advantage.

CSP uses mirrors to concentrate sunlight onto a receiver, heating a fluid to drive a steam turbine. Molten salt storage (at 565 degrees C) can hold 6-12 hours of thermal energy, allowing generation into the evening. PV converts photons directly to electricity with no moving parts, no steam cycle, and no inherent storage.

Compare costs. CSP LCOE in 2024: $80-150/MWh, depending on storage duration. PV LCOE: $20-40/MWh. PV plus 4-hour lithium-ion battery: $50-131/MWh. Even with storage added, PV undercuts CSP.

If CSP can store energy cheaply in molten salt, why doesn't longer storage duration save it?

CSP's niche is shrinking. CSP requires direct normal irradiance (DNI), limiting it to deserts. PV works with diffuse light anywhere. CSP's mirror fields require 5-7 acres per MW; PV needs similar land but at a fraction of the capital cost. As battery costs continue declining, PV plus batteries competes with CSP even for dispatchable solar in high-DNI locations.

CSP survives in niche applications (process heat, long-duration thermal storage in desert locations), but the contest was decided by cost, not by the storage advantage CSP started with. PV's manufacturing scale beat CSP's physics.

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