There are a variety of Photovoltaic Panel manufactures, each panel (module), even within a single company, has its pros and cons. Currently, there are 2 primary types of modules: Polycrystalline and Monocrystaline. There is a third type, thin film which we discuss below. The Polycrystalline are slightly less expensive, but have a lower performance at ambient temperatures above 95 degrees and are based on older technology. The Monocrystalline panels consistently perform better, have newer technology, but are slightly more expensive. The manufacturing of mono-crystalline panels is increasing and the manufacturing of poly-crystalline is decreasing.
The solar panel market is much like a commodities market: price is often determined by supply and demand. The December 13th 2007 congressional vote to allow the solar investment tax credit to expire at the end of 2008 is causing many commercial projects to rush to get solar panels. Presently there is a bottleneck in the supply process with the silicon refiners.Some manufacturers can not get enough refined silicon to meet the temporary demand. Manufacturers that refine their own silicon, such as SunTech Power, have an advantage in these high demand markets. This rush is creating a high demand issue in the U.S. and distributors have warned us that there will be supply problems and increased prices in 2008. Some manufacturers have already announced price increases.
The DC wattage of a single shipment of panels has more to do with how each “batch” of silicon is grown; therefore, most manufacturers will continue to release a range of panels of various wattages but the same size, depending on the performance of the silicon.