Abstract—it is a bad idea when hearing that fossil fuel is almost run out. Researchers always keeping on eyes this problem and try to find alternatives. One of this alternatives is the Renewable Energy Resources (RESs). When RESs penetrated conventional power systems, uncertainty and sudden load frequency deviation are expected to occur that may lead to instability in power systems. To hold over the power system frequency stability and the power flow in transmission lines to their rated values, Load Frequency Control (LFC) is an important factor to achieve better stability performance. LFC plays an important role in balancing the generation against the load electric demand. This paper addresses the usage of a simple shifted PI controller as a load frequency controller in two similar areas, each containing three different units when one of which is penetrated with a wind energy station as a seventh unit. Simulation results will demonstrate the effects of the proposed controller when it can diminish the variation in load frequency and leads to obtain a better stability performance.