Spring 2013 Issue
Demand fulfilment Seawater desalination is one of the main issues for the Kingdome of Saudi Arabia. Most of the oil burning power stations in KSA are built near the sea shore and produce desalted water beside electricity in cogeneration by using the waste heat at the condenser of a steam turbine, an established concept for decades that has proven its validity and cost effectiveness. This proven concept can be continued with Concentrating Solar Power (CSP) power stations that are capable to produce electricity day and night thanks to their thermal storage capabilities. Using mainly a steam turbine for power generation, they fit optimally in the existing scheme and can even take over for thermal power stations that are out-phased. According to the published plans of the government, 25 000 MW of CSP and 16 000 MW of photovoltaic power (PV) are planned to be installed till 2032.
In Pictures: Hani El Nokraschy
This mix beside existing fossil power stations is justified when having a closer look at the typical pattern of electricity demand, which differs according to the seasons. Figures 4 and 5 show the main characteristics of warm countries, typically having a higher demand on electricity in summer than in winter. In KSA it is even an exceptionally large difference as the winter peak demand is about 60% of the summer peak demand. This correlates well – globally seen - with the sun energy received by the desert areas, thus it is obvious that this kind of renewable energy will have an exceptional advantage in KSA. Figure 3: Professor Hany Al-Ansary, Chairman of the Mechanical Engineering Department in the College of Engineering at King Saud
As known, PV delivers its peak electricity at noon. This correlates quite well with the expected demand in summer 2030. It is typical for KSA that the electricity demand peak is around noon in summer because of the intensive application of air conditioning.
In contrast to KSA, the summer peak in Mediterranean countries is in the early evening (whereas demand in summer is about 20% higher than in winter).
A more detailed insight to the curves reveals that in winter the peak is during the evening, while in summer it is around noon. Accordingly using PV will develop enough electricity especially in summer around noon and CSP power stations can take over for the evening and base load all the year.
Peak Swap over the borders The fact that neighbouring countries have different peak day time gives the chance of electricity swapping between them to compensate the peaks and thus avoiding a part of investments in peaking power stations for both countries.
Figure 4: Summer electricity demand pattern.
Figure 5: Winter electricity demand pattern.
University and Dr. Thiemo Gropp, Director of the DESERTEC Foundation visiting the testing facility.
Explanation: Typical electricity demand pattern expected 2030. Source: KA-CARE, Khalid Al-Sulaiman.
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Figure 6: Typical PV electricity production during the day.
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