Eoin Treacy's view This chart from the USA's National Renewable Energy Laboratory for is one of the best illustrations both of solar technology's development and the power of new disruptive technology to make established products obsolete in a short period of time.

/A delegate at the May venue for The Chart Seminar in London described the new generation of solar cells as akin to the evolution that occurred in Christmas tree lights when they went from running in series to in parallel. This represents a significant productivity jump. As the pace of technological innovation persists the potential for new innovative products to make the current generation of technology obsolete remains high.

It is impossible to say just how long it will take the cost of solar to reach grid parity and for storage technology to provide base load but when that occurs an additional energy revolution is likely to take place.

After a disastrous crash, extensive consolidation and some significant trade disputes, solar cell manufacturers appear to be on a recovery trajectory. (Also see Comment of the day on June 18th) . This week alone Canadian Solar, China Sunergy, Hanwha SolarOne, ReneSola and Trina Solar all hit at least new 12-month highs.