Wind/solar GHG payback period

I found myself wondering what the GHG payback period for wind and solar power was. That is, say X tons of CO2e are emitted mining the silicon, manufacturing the solar panel, transporting and installing, etc., and after that the solar panel generates electricity essentially emission-free. How long does it take an existing coal plant to emit X tons of CO2e (a.k.a. how long does it take the renewable technology to "break even")?

Wind is pretty good - less than one year, according to one source.

I wasn't able to find that exact number for solar (most discussions of payback are around financial payback for people interested in installing solar panels on their houses), but this page calculates the energy payback time (slightly different, but a reasonable proxy) to be ~1.5-2 years in southern Europe.

Obviously both of these numbers depend on the capacity factor of the renewable power installation (i.e. how often does the wind blow/sun shine), the technology used, the source of energy used in manufacturing, and the type of power generation it is displacing (the best baseline in my opinion is an existing modern coal plant).

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