How does the BlueSolar PV/CSP panel performs against a pure PV panel?

The BlueSolar panel loses around 15% in a Solar Simulator. However, the operating temperature is around 15C lower which leads a better Performance Ratio. This lower Temperature partially compensates and the real performances are quite similar. However the big differentiation is that the BlueSolar panel is recovering 50%+ energy via thermal, which is converted to electricity via steam turbine with a 45% efficiency, so the overall system efficiency is increased around 50%.

 

The heliostats do not track the sun perpendicular so you are having some cosine losses?

Correct, in a North Solar Field configuration the cosine efficiency is around 85%. In a standard PV 1 axis is around 87-88%, depending on the latitude. BlueSolar Panels can operate full perpendicular at high cosine hours (ie East corner in the morning and West corner in the afternoon), so the overall cosine loss is quite similar to a standard PV 1 axis.

 

The heliostat with the BlueSolar PV panel provide less thermal load to the receiver compared to a mirror heliostat?

Correct, but it is is way more efficiency when you add the TS and PV performance in a BlueSolar panel compared to a pure TS performance coming from a mirror based heliostat. This means that you need much less heliostats to reach a certain degree of production. The lower thermal load means less operating hours of the turbine, which can be reserved for peak hour production. Additionally you can add electrical resistance heaters to provide more thermal load and extend the hours of turbine operation, which means that you can design the molten salt receivers for lower output temperatures. This leads to lower receiver cost and solar field costs.

 

How would you operate the BlueSolar plant?

The PV production will be used for daytime and the turbine production would be reserved for peak time production. A standard tower CSP plant generates more thermal load, which is used for turbine production day and night. Both energy profiles are comparable.

 

A pure BlueSolar plant can produce baseload energy profiles?

BlueSolar, due to the nature of the partial reflectance of the PV/CSP panel, is ideal to provide PV during day and a limited number of hours of turbine for peak production. If a baseload profile is needed (6000+hours), standard PV with resistance heaters need to be incorporated to extend the thermal load, which leads to design simplifications for the BlueSolar plant in terms of receiver output temperatures.