# Economic Energy Allocation of Conventional and Large-Scale PV Power Plants
## 4 Discussion  
As discussed in Section 1, the proposed model considers both the technical aspects and the contractual provisions. The confidentiality of the contracts between the power distribution companies and the power plants makes the research task difficult.  
For the assumed case, it is noticed that after the commissioning of Alkharsaah, the total cost was reduced by 20,800,000 $, which represents a 1.65% cost reduction as reported in Tables 4 and 5. Even though the energy price is not the highest for F power station, the energy reduction is from F power station. This is because there is no water constraint for that power station. The cost reduction will be much higher if the water demand constraint is lesser in the different power plants. This shows the importance of producing and desalinating seawater using RO technology. Energy generation and water production are connected. There are two main technologies for seawater desalination: the conventional thermal using multi-stage flash (MSF) and reverse osmosis (RO). For the thermal technology, there is a minimum amount of energy to be generated in order to produce the required amount of water. However, for the RO technology, the minimum amount of energy to be generated to produce the same amount of water is much less. This will lead to a better energy allocation for the new power plants [26; 27].  
When the PV contribution is higher, the energy reduction will be more from the different power stations. Moreover, if there is a storage facility with the PV power plant, there will be less power reduction from the other power plant. However, the storage facility is significantly expensive. Therefore, there are no storage batteries for the PV mega projects (5 MW and above) in which the generating energy will be injected directly into the power grid.  
Furthermore, the electricity demand pattern differs between summer and winter in Qatar. For the summer period, the peak demand period is in the afternoon period. The peak is coming during that period due to the air-conditioning load due to the extremely high temperature and humidity values. On the other hand, the winter peak demand is in the evening due to the lighting load since the weather is fine with moderate temperature values. As a result, the power from Alkharsaah PV power plant will be easily evacuated during the summer period since there is no storage facility. However, during winter, there will be no PV generation during the peak period since it is coming after the sunset. This will lead to more power reduction from the other power plants during the day in winter. However, the six gulf countries have been electrically interconnected since 2009, and the Arab countries' interconnection is in the implementation phase [28]. Therefore, this will facilitate exchanging the power between the different countries and better utilization for Alkharsaah PV power plant and any new renewable energy projects.  
Figure 8: Available and allocated energy to power plants with Alkharsaah.  
As a result, additional renewable energy plants would drive down the purchase costs even further; however, optimization studies would be required to quantify the cost savings and ensure that the constraints mentioned in Section 2 do not hinder these cost savings.  
It is noted that the proposed model requires excessive data for the power plants. Therefore, Qatar's electricity system with Alkharsaah PV power plant was considered a case study due to having the required data.