Following on from http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=148&page=1#Item_14
check this fascinating site http://www.energyinnovations.com/index.php
They're following several lines of development to collect solar energy photovoltaically, (though their favourite future project uses a Stirling Engine instead of PV). Their approach to getting area-efficiency up and cost down is to make the actual PV very small but concentrate sunlight from a wider area onto it by steerable mirrors that track the sun.
It obviously pays-back best in very sunny climates but one day no doubt such technology could be optimised for UK, especially if as expected we get hotter summers.

Posted By: fostertomoptimised for UK, especially if as expected we get hotter summers.

Air temperatures have no relationship to the amount of solar radiation received per square metre. No amount of global warming changes the latter - an amount purely determined by latitude. Of course, if the UK received more sunshine hours, that would have an effect, but the amount of energy per square metre stays the same.

Paul in Montreal.

More here..
http://www.emcore.com/product/ter_t1000_cells.php