Initial Performance History - O&M Lessons Learned
Kuno Schallenberg
Kuno.Schallenberg@de.lahmeyer.com
+49 6101 55 1886
26 August 2013
Lahmeyer International GmbH
Engineering and Consulting Services
Energy Division; Business Unit Renewables and Economics
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Solar Tower Technology
Brief facts on the current status:
• 3 operational projects considered commercial:
– PS-10 (10 MW)
– PS-20 (20 MW), and
– Gemasolar (20 MW)
• Large commercial projects under construction (e.g. Ivanpah)
• Some pilot and demonstration experiences around the
world (e.g. Solar One, Solar Two, Themis, etc.)
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Tower Project Focus: Gemasolar (Spain)
Source: Torresol
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Gemasolar: Key Data
Source: Torresol
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Gemasolar: Layout
Decoupled
System
Source: Torresol
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Gemasolar: Plant behaviour (full summer week)
Meinel DNI (W/m²)
Actual DNI (W/m²)
Heliostats focusing (u)
Receiver Power (MWt)
Storage Level (%)
Gas use (kg/s)
Net Output (MWe)
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Source: Torresol
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Gemasolar: Operation - Preliminary Results
• Plant is still on ramp-up period (2nd operational year)
• Performance exceeds expectations on clear sky days but is lower than expected on cloudy
days
• Plant can operate continuously 24 hours/day (mainly summer)
• Fine control of solar field and receiver temperature achieved
• Cleanness factor of the solar field exceeds 95%
• Storage tanks loose around 1°C/day in average
• Water consumption per year rounds 400,000 m³
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Gemasolar: Operation Event – Frozen Receiver
• Event: Frozen salts on receiver tubes
• Cause: operation exceeding boundary conditions
(high winds)
• Solution: gradual heating of the tubes using the
solar field
• Result: salts were melted and tubes freed
• Consecuences: no mechanical or structural
damages to the receiver
Source: Torresol
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Gemasolar: Maintenance
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Source: Torresol
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Gemasolar: Maintenance – Key Facts
• Typical maintenance activities: preventive, predictive and corrective
• Major emphasis on predictive maintenance, especially on non-conventional equipment
(e.g. receiver, salt pumps, etc.)
• Annual plant inspection (scheduled corrective maintenance) with a duration of 3-4 weeks
• Turbine has shown no signs of degradation, performing substantially better than in other
CSP plants
• No perceived degradation on Receiver
• No special maintenance activities on salt system (no corrosion noted)
• Exceptions: valves (salt system) and kettle
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Gemasolar: O&M Personnel
• Operation (on site):
– Around 20 employees which include supervisors, EHS, process engineers
and operators, divided into 5 shifts
• Maintenance:
– Around 30 employees which include supervisors, electromechanical
technicians, chemical engineer and cleaning crews
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Gemasolar: O&M Costs
15%
8%
Owner's Costs
EHS Costs
General Costs
Maintenance Costs
29%
46%
Operation Costs
2%
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Trough Technology
Brief facts on the current status:
• Around 3 GW installed worldwide
• Large commercial projects still announced
• Almost 30 years of operational track record (SEGS I built on
1984)
• Relatively mature O&M experience
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Trough Project Focus: Typical 50 MW installation with TES (Spain)
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Source: Torresol
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Trough Case Study: Key Data
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Source: Torresol
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Trough Case Study: Typical Plant Layout
Source: Torresol
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Trough Case Study: Plant behaviour (clear and cloudy days)
Stored Energy
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Gas Heater
Turbine Output
Source: Torresol
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Trough Case Study: O&M Results - Spain
• Performance results are not similar/homogeneous within the plants installed recently
(last 5 years) in Spain
• Some plants register 15 to 20% higher annual performance compared to expected values
• Experience from SEGS plants allowed optimization of O&M e.g. high performance,
effective maintenance (predictive) and cost reduction
• Major O&M incidents relate to HTF leakages (e.g. ball joints, flexible hoses), HTF pumps
failure, HTF filtration into water/steam cycle, broken absorber tubes
• There are no major incidents with the operation of the TES reported
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Conclusions & Lessons learned
• Operation with molten salt systems as HTF is more delicate on changing weather conditions
(e.g. cloud passages)
• Decoupled systems with TES allow reduction and/or elimination of weather disturbances on the
solar field (e.g. cloud passages), allowing a better operation of the turbine
• No special events detected on the operation of molten salt storage systems
• O&M cost reductions on existing plants are very unlikely without losing plant performance
• Increasing project size or multiproject development might be the only way to reduce O&M
costs
• CSP integration to existing thermal power plants represent a significant reduction on O&M
costs for the solar part (e.g. almost no additional labor)
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Thank you for your Attention
Questions?
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