Grid parity - you should know - is the point at which photovoltaic electricity is equal to or cheaper than mains supplied electricity and is regarded as the Holy Grail by solar followers. At this point, solar production will literally take-off - without need of subsidy - because as a forward purchase of electricity, it is cheaper and the highly distributed grid becomes reality. In some respects, grid parity is the less glamorous energy equivalent to Ray Kurzweil's Singularity, when artificial intelligence exceeds human intelligence - which he predicts will happen in 2045 - and machine intelligence drives economic growth faster and faster at a pace and rate of change we couldn't easily comprehend.

Now back to the sunny stuff. An excellent piece in today's Guardian by Ashley Seagar provides us with a feast of food for thought on the prospects of solar energy in the next few years. The big question is simply this; when will the solar industry achieve grid parity?

Today, the optimists would say, 2-5 years at most and their arguments are roughly as follows;

i) Higher than anticipated oil prices and other fossil fuels are pricing in solar more quickly than expected
ii) The great polysilicon shortage - where demand significantly exceeded supply - will end in 2009 lowering signifantly the input raw material costs of solar wafer and module m