Source: ESTELA

Parabolic Trough plants collect the direct solar radiation in collectors consisting of parabolic trough mirror concentrators with a linear absorber tube. The heat transfer fluid is normally synthetic oil which circulates through the tubes at inlet outlet/temperatures of 300/400 ºC. Higher outlet temperatures would increase the overall efficiency of the plants but they would degrade the oil. That is why other HTF like water with direct steam generation and molten salts are being considered. The typical size in Spain is 50 MW due to regulatory restrictions, nevertheless this is a very flexible concept that can fit with few MW or go up to several hundred MW. Typical storage capacity in Spain is 7 hours at nominal power.

In Europe, the installed capacity of parabolic trough plants in operation reaches 1650 MW and 623 MW are under construction. The parabolic trough technology is the most mature available on the market with a track record since the 1980’s.

• Uses parabolic mirrors to concentrate solar radiation on linear tube receiver
• Provides heat storage capabilities
• Temperature of the working fluid: 400ºC for synthetic oils. Molten salts or direct steam generation are not commercially proven.
• First plants came on line in the 80s and are still working
• Has operational experience, modularity and a large number of components providers
• Size: 20 to 300 MW
• Solar energy to electric power performance: Design point 16%. Annual 14%.
• Prices of PPA that will make projects feasible: between 15 and 20 c€/kWh depending on the level of solar radiation, size of the plant, capacity factor, financial conditions, etc.
• Proven utility scale technology