The payback time on photovoltaics is getting better. Not, you might thinkk, because economies of scale are making the manufacturing process cheaper. Not because they are getting more efficient. Nope, it's because the unit cost of electricity generated by other means is going up *groan*.More here.
I spotted a letter in the guardian today - complaining about the 'hidden' CO2 emmissions of wind turbines. Yup, the anti wind league is now bleating on about the energy used to make the 'wretched things' - for example in the concrete bases. Funny that, what do coal fired power stations use for foundations then ? I don't think they publish the enbergy payback time for fossil fuel plants.