Thanks for your comment. To be clear, I am not suggesting the UK should avoid building new nuclear. As I say, it does look like the UK needs new nuclear. Rather, at these sorts of prices (even if the £80/MWh DECC projects is achievable for nuclear), imports of renewables also appear worth a closer look as part of a portfolio of low carbon generation that includes nuclear. But as yet they do not seem to have received the focus they warrant.
The cost comparison between nuclear and imported renewables is largely unaffected by the cost of other new UK generation. The only place the price of other UK generation features in the calculations is in the contract premium, where I have assumed a lower market price for electricity than the cost of new gas plant that DECC estimates, in part because I have, as noted, assumed that it will prove difficult in practice to raise the carbon price to their assumed level of over £70/tCO2. The additional value of the longer contract may be higher or lower than I have estimated, but if the longer contract did not have value the case the owners would presumably not have sought such a long contract.
There is, as always, a range of assumptions you can adopt in making these kind of adjustments. For example I noted the potential decrease in the daytime price premium in future. But provided solar costs fall significantly over the next decade (this is the most critical assumption) it does not appear that changes to other assumptions would invalidate the conclusion that imported renewables look potentially quite cost effective as part (but by no means all) of a programme to decarbonise the power UK power sector.