Very interesting article from Circular Ecology on the embodied carbon footprint of PV panels and what that means in terms of (carbon) payback in the context of a rapidly decarbonising UK grid.

It's been taken down and edited once already to add a few caveats (presumably following feedback/pressure from the industry) but raises a few interesting points. The comparison with wind power is particularly enlightening.

http://www.circularecology.com/solar-pv-embodied-carbon.html#.XjGv1JVLE-W

I'd be very surprised if a new PV panel in the UK displaces any low-carbon generation though... Still plenty of fossil generation to displace! And that's the marginal (higher unitcost) generation, which gets turned down whenever there's incremental pv.

And what with electrification of transport and heat, and lifetime of the remaining nuclear, I don't see that changing soon....

The article has used 'average' instead of 'marginal' intensity which is why they get strange conclusions. They acknowledge this in an end note, but state that it's too difficult to do the numbers otherwise.