Oman Electricity Transmission Company (OETC) is facing some operational challenges linked to the growing share of Combined Cycle Gas Turbines (CCGTs) and to must run constraints for the production of desalinated water. This is due to the fact that the Omani power generation system has, in the last years, been expanded with CCGTs in order to accommodate the growing electricity demand of the sultanate with cost-efficient generation capacities. The share of Open Cycle Gas Turbines (OCGT) in the installed capacity has therefore been reduced significantly. In addition, considering the planned decommissioning of old OCGTs, it is anticipated that this trend will be strengthened in future years. Since conventional CCGTs are generally less flexible than OCGTs from an operational point of view (e.g. higher start-up time), this is likely to lead to some technical operation difficulties. With the foreseen installation of non dispatchable renewable generation, such concerns are likely to become even stronger in the future.

The objective of this paper is to investigate if the present and future mix of generation units is sufficiently flexible to follow load variations in constraining situations. The study is performed at defined critical weeks for 2015 and 2020. A state of the art unit commitment and economic dispatch tool is used for this purpose. Some desirable evolutions of operational practices are highlighted as output of the paper, including more frequent cycling of CCGTs.

Renewable energy is considered for horizon 2020 in Oman. Therefore the impact of the foreseen renewable capacities (solar and possibly wind power) on the generation schedule is also investigated. Due to the moderate level of expected installed renewable capacity (maximum 350 MW), only limited impact is observed.