Impact of high renewable penetration scenarios on system reliability: two case studies in the Kingdom of Saudi Arabia

Abstract

Renewable energy sources (RES) are close to grid parity compared with conventional generation. Therefore, it is important to consider proper costs to assess the economics instead of technological aspects only. While some scholars are in the opinion that RES only adds complexity - as RES production is volatile and stochastic - others share the opinion that RES has value in terms of energy savings, as well as capacity savings, and contributes to the reliability of an energy system. Instead of analyzing the losses as a result of adding RES, it should be focused on the overall system economics, as this is more important than if more or less electricity is lost for whatever reason. Economy of Scale (EoS) can have significant impact on project evaluation, and therefore should be considered in medium- and long-term planning exercises. As a result of not limiting RES to minimize losses within the system, the most economic systems show penetration for photovoltaic of above 80 percent, and for Wind of above 55 percent, on peak demand for both locations. This shows that significant energy out of RES is not used during the winter, as the demand is less than 50 percent of summer RES, adding value to the system, as RES saves fuel and increases system reliability by decreasing the required electricity from conventional generation. Dependent on the location, between 30 and 40 percent of peak demand on renewable technologies are required before curtailing takes place. It looks like the concept of Effective Load Carrying Capacity (ELCC) is not that important anymore, as prices for RES came down significantly within the last decades. The RES quality still plays an important role but is getting less important as RES costs are decreasing further. It is expected that also average RES quality site will be more economic in several years.