*4.1. Power Quality*

The power quality index is used to measure voltage and current waveform distortions in pure sinusoidal ideals [43]. Variations in solar irradiance and wind speed trigger the negative effect of high-variance DG plants. Consequently, the BESS added to the DG plant has the potential to smoothen temporary power fluctuations. In this situation, it is viewed as an extra cost component with respect to the RES plant that serves as a revenue system. The provision of economic incentives to plant owners to reduce power fluctuations is a technique used to compensate for revenue losses [45,46].
