Where does the energy loss of concentrated solar power go?

There are two ways to concentrate solar radiation: Reflection and Refraction.

In both cases, there are losses associated with imperfections in the surfaces (of mirrors in one and of lenses in the other). These imperfections result in two sources of inefficiency:

• some of the redirected radiation will miss its target (whether it be a photoelectric cell or a boiler)
• some of the radiation will be absorbed by the material in the lens or mirror, converted to heat and dissipated

After the remaining radiation hits its target, there will also be energy conversion inefficiencies due to electrical and mechanical losses.