If you think about it (and Greenbang regularly does) so many of the world’s greatest and most unanswerable questions start with the the word when.

‘When was the universe created’, for example, or ‘when’s tea ready?’ or ‘when will there be a harvest for the world?’ or ‘when do the binmen come?’ So many questions, so few answers.

Still, at least one of those head-scratchingly tricky brain teasers – when will solar achieve cost parity with traditional electricity sources? – has been solved by industry analysts iSuppli.

If 40 percent cost reductions in photovoltaic cells come off as expected,well, then parity could come in under five years.

Says iSuppli:

many regions throughout the world will soon reach grid parity—a point at which PV electricity costs the same or less than power derived from the electrical grid. PV grid parity is expected beginning 2012 in nations where sunshine is plentiful and constant, and 2018 in areas of the world with adequate or medium sun exposure.

And there’s more:

Global production of PV cells is expected to rise to as much as 12 Gigawatts (GW) by 2010, up from 3.5GW in 2007. By 2010, as many as 400 production lines in the world that can produce at least 1 Megawatt (MW) of PV cells per year will be in place, representing a four-fold increase from about 90 to 100 production lines in 2007. Factories capable of 1GW of annual PV production also will be established in the future to ensure continued strong delivery of PV cells to the market.

“The market for PV cells is estimated to grow by 40 percent annually until 2010, and 20 percent beyond,” said Dr. Henning Wicht, senior director and principal analyst, MEMS and photovoltaics, for iSuppli. “Nearly all market participants plan to increase their sales by a Compound Annual Growth Rate (CAGR) of 40 to 50 percent during the next few years.” Wicht noted that heavy investments will be required to finance the expansion of PV cell production. Each PV factory will require an investment of $500 million and more, will employ as many as 1,000 workers per site, and will generate annual revenue of $1 billion per year or more, putting them into the size, cost and employment range of semiconductor fabs.

Tags: cell, isuppli, photovoltaic, semiconductor, solar