23rd International Conference on Concentrating Solar Power and Chemical Energy Systems
Reflected Solar Irradiance for CSP Plants Simulation: Impact and Importance for Solar Resource Assessment
Plan
2
Objectives Context Methods for soiling assessment Results and discussion
Objectives
2
Perform more accurate simulations of CSP plants expected output based on reflected DNI (on a soiled surface)
Find the most optimal method to assess soiling on operating power plants
Context
3
• Motivations and opportunities for RDNI based simulations
High soiling conditions in Benguerir;
High impact on plant output in Benguerir;
Need for Yield analysis with real site-soiling
measurements;
Availability of a +10000m2 linear
Fresnel solar field;
Manual Soiling/Reflectivity
measurement devices are tedious;
Availability of CSP plants output
simulation;
Possibility to access the output of future CSP
projects taking into account the soiling
factor
Solar field soiling mapping
5
• Solar field reflectance mapping one
week after cleaning (5th June)
• Average reflectance for the entire
solar field 83,7%
• Reflectance peak 95%
• Reflectance pit 68,1%
Solar field soiling mapping
6
• Solar field reflectance mapping five
weeks after cleaning (4th July)
• Average reflectance for the entire
solar field 66,8%
• Reflectance peak 91,5%
• Reflectance pit 48%
Reflected DNI measurements
4
orkneywind.co.uk
• Measurement of reflectance/RDNI done continuously with the traCS
• Cleanings performed on mirror sample every two weeks
Power plant simulations
7
• Short term simulations performed with EBSILON (single day simulation)
• Long term calculations done with Greenius and an internally developed code
Short terms simulation results
8
• Performance loss highly linked to weather conditions stiffness
• Higher performance drop with higher irradiance fluctuations
• Lower performance loss with stable weather
DNI
RDNI
Pout (RDNI)
Pout (DNI)
∆P≈20KWTh
The DNI and RDNI values over the experiment period
• The values of the 3 DNI inputs for simulation over the measurement period.
Higher performance drop with higher irradiance fluctuations
• Soiling affect’s the DNI value very much and it’s in accordance with the
Cleanliness values measured by TraCS.
• The power output has a similar behaviour with the DNI
• The difference is small with low DNI values.
The Power output simulation over the experiment period
Long term simulation results
9
• Over the period of Mai - July
• Average Cleanliness drop 15,8%
• Average performance loss 22%
0,00%
20,00%
40,00%
60,00%
80,00%
100,00%
120,00%
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Ref
lect
ed D
NI/
Per
form
ance
dro
ps
(%)
Cu
mu
late
d ir
rad
ian
ce (
W/m
2 )
Irradiance (DNI) Cleanliness Production loss
Conclusions and perspectives
10
• Higher performance loss du to mirrors soiling may justify the need for
accurate soiling measurements before selecting CSP project sites
• Irradiance and performance losses for Benguerir are relatively high, hence
more frequent cleanings are necessary (once per week)
• Complete simulation for one year will provide a firm prevision of
performance loss for Benguerir
Thanks for your attention!
El Ghali Bennouna Thermal systems Research Institute on Solar Energy and New Energies (IRESEN) ................................................................. Green Energy Park, Km 2 Route Régionale R206, Benguerir ................................................................. Tél : + 212 (0)620 30 75 10 Fax : + 212 (0)537 68 88 52 E-mail : [email protected] Skype : ben.elg ................................................................. www.iresen.org www.greenenergypark.ma www.energy-science.org www.pv-science.org www.csp-science.org www.wind-science.org
www.minwatercsp.com [email protected]