29 November 2011
Located some 90 kilometers south of Cairo and in reaching distance of the water sources of the River Nile, the integrated solar combined cycle power plant of Kuraymat is a first example of large-scale use of solar energy in Egypt.
The Kuraymat location features a high intensity direct solar radiation of more than 2,400 kilowatt hours per square meter and year. Put into commercial operation in June 2011, the project is based on parabolic trough technology integrated in a combined cycle power plant using natural gas as fuel. At a total capacity of 140 MW and total investment of US$ 340 million, the capacity of the solar island is 20 MWel or approximately 61 MWth.
Solar islands at the integrated solar combined cycle power plant of Kuraymat, Egypt. Image courtesy Paul Langrockt, Solar Millennium.
The project layout does not include a stand-alone solar solution; neither does it contain heat storage. Instead, the basic principle of the technical concept is to unload the gas-powered cycle. For this, the solar field produces heat during sunshine hours, and that heat is transported through a heat transfer fluid (HTF) cycle – in this case using oil – to a heat exchanger that is connected to the heat recovery steam generator of the combined cycle power unit. By this, the energy output of the steam cycle rises and gas can be saved (see figure1).'
Figure 1: Technical concept of Integrated Solar Combined Cycle of Kuraymat
Surrounded by wind breakers on two sides to reduce wind loads, the collectors – each measuring approximately six meters in height – were being installed in the solar field in several hundred meter long rows of parabolic troughs. In total, 1,920 collector modules in 160 collectors with an overall surface of about 131,000 square meters automatically track the sun. In order to maintain a maximum of efficiency, two washing trucks clean the mirrors periodically and need approximately 20 m3 of water per day. Each half of the solar field is being cleaned; therefore the entire solar field is cleaned every second day.
Solar collectors. Image courtesy of Piet van Lingen
Owned by the New and Renewable Energy Authority of Egypt (NREA), German Fichtner Solar acts as the engineering interchange between the EPC Contractor of the Combined Cycle, Spanish Iberdrola and Egyptian Orascom CI, which acts as EPC Contractor of the Solar Island. German-based Flagsol, a subsidiary of Solar Millennium, acted as technology provider. Flagsol designed the solar field and the heat transfer fluid (HTF) system in the absorber pipes, delivered the control unit for the solar field and other key components.
Orascom Construction Industries will operate the solar section of the power plant for a period of two years before it is handed over to the owner. Flagsol consults Orascom in regard of operation and maintenance with up to 6 people on site. The experience gained will be useful in future power plant projects. The results of the first months of operation are positive: The production at Egypt’s first major solar-thermal power plant exceeds expectations considerably. The solar field generates nearly 8% more energy on average than estimated.
Written by Andreas Breyer, Contributing Editor - Germany
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