In my previous post we discussed the most common type of solar module utilized today, crystalline silicon panels, which are encapsulated in glass. Another type of rooftop power generation that produces electric energy is Concentrated Solar Power, or CSP. CSP uses lenses or mirrors to concentrate solar thermal energy onto a small area such as a tower. Typically, the mirrors are positioned on the roof to reflect sunlight to the tower mounted on the ground at one end of the building. The tower houses an engine (usually steam), to drive an electric generator.
CSP requires very clear skies to work most effectively, and steam generation requires a fair amount of water which can be an issue in hot, dry climates. Compared to PV, more maintenance may be necessary due to the moving parts in trackers and generators. But focusing the sun in this way also has several advantages.
First, less space is required for the collection units; so less land or rooftop space is required. The cost per watt for CSP is currently par with PV, but has the potential to be half that of PV. CSP steam generators produce AC power so they can integrate directly into existing infrastructure without power inverters. With natural gas back-up or molten salt heat storage systems, CSP has the potential to operate continuously in the event of extended periods of cloudiness or shading of part of the array. CSP is projected to have a larger share of solar power generation within 10 to 15 years due to its efficiencies and potential reduction in cost (and by extension – the ability to generate power more cost effectively) due to technological advancements.