Posted by: africanpressorganization | 1 March 2011

Concentrated Solar Power (CSP): Millions in Losses With Wrong Components


Concentrated Solar Power (CSP): Millions in Losses With Wrong Components



NUREMBERG, Germany, March 1, 2011/PRNewswire via African Press Organization (APO) / — According to calculations by DLR (German Aerospace Center) the increase in yield resulting from annealed parabolic mirrors over a period of 25 years amounts to more than seven million Euros. This is based on independent figures and on the company’s practical experience with more than seven million solar mirrors that have been installed in the field for 30 years already.


In the industry it is discussed whether CSP solar mirrors made from tempered or annealed glass achieve a better overall performance.

Manufacturers of tempered mirrors advertise lower costs for mirror replacement. This calculation fails to take account however of the higher plant yield that solar mirrors made of annealed glass achieve owing to their better precision collector interception.

The key parameters for the yield of a CSP plant are the bending properties of the mirrors. The basis for assessing the bending properties of a solar mirror is the focus deviation (FDx). This measures the frequency distribution of the real focus deviation in transversal (x) direction of the reflected beam from the ideal focul line of the collector parabola.

Consequently, the lower the FDx value, the higher the plant yield. According to the calculations of the DLR each millimetre of decreased scattering loss amounts to an additional plant yield of 11.25 million Euros[1] over a period of 25 years.

Based on these data, FLABEG Holding GmbH, the market leader in the field

of glass finishing and the leading international manufacturer of solar

mirrors has made the following calculation:

Yield and cost summary for a 50 MW plant with 23,000 tubes and 200,000


Annealed Tempered


Additional yield due to + 7,875.000 EUR[1] 0

better precision

collector interception


Costs for mirror – 650,000 EUR – 42,500 EUR

replacements due to

glass breakage

Costs for absorber tube – 65,000 EUR 0

replacements due to

glass breakage

Total + 7,160.000 EUR – 42,500 EUR


Additional yield of the plant with annealed solar mirrors after

25 years:


7,117,500 EUR


Bases of calculation:


Average mirror breakage rate: annealed 0.20 %[2], tempered 0.01 %[3]

Average absorber tube breakage rate: annealed 0.025 %[2], tempered 0 %[3]

Precision rate / focus deviation: annealed FDx < 8 mm[4], tempered FDx < 8.7



[1] Mean values according to calculations by the German Aerospace Center,

reference values: plant capacity 50 MW, period of observation 25 years,

nominal glass thickness 4 mm

[2] Average values according to KJC/Harper Lake, period of observation

10 years, nominal glass thickness 4 mm


[3] Tempered glass manufacturer’s indications


[4] Current average focus deviation of FLABEG parabolic solar mirrors


The result shows that during long-term observation, the annealed solar

mirrors are markedly more profitable: More than seven million Euros of

additional plant yield is achieved over the period of 25 years.


Axel Buchholz, CEO of FLABEG Holding GmbH, is able to confirm this

calculation based on independent figures from his own practical experience:

“Competitors advertise with extrapolations. In contrast, our solar mirrors

have been in the field for 30 years already and have proven their durability

and constantly high performance”.


Another item of practical experience to be borne in mind: “Glass breakage

generally arises only at the corners or edge of a mirror. Tempered glass

shatters into a thousand individual pieces in this case, which may result in

considerable damage to other components in the field. Our annealed mirrors on

the other hand continue to remain operational”.


FLABEG, founded in 1882, is an independent company with 13 facilities in

Europe, America and Asia. FLABEG is active in the commercial sectors of

automotive mirrors, solar mirrors and technical glass; specializing in all

processes of glass finishing. As the pioneer of solar technology with a

worldwide network, FLABEG produces mirrors for all CSP-applications –

Parabolic Trough, Dishes, Tower and Linear Fresnel. Due to latest coating

technologies our solar mirrors are characterized by a reflectivity of more

than 95%. FLABEG sets technological standards in terms of the company’s core

competencies – bending and coating.




For further informations contact:


Kerstin K?tter

Head of Marketing & Communication

FLABEG Holding GmbH

Waldaustr. 13

90441 N?rnberg

Phone: +49-911-96456-0

Fax: +49-911-96456-465




Source: FLABEG Holding GmbH


For further informations contact: Kerstin K?tter, Head of Marketing & Communication, FLABEG Holding GmbH, Waldaustr. 13, 90441 N?rnberg, Phone: +49-911-96456-0, Fax: +49-911-96456-465,


FLABEG Holding GmbH


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