Harmonic analysis of annual global irradiation in the cities of India

Abstract

Intermittent renewable energy sources, installation and maintenance of sophisticated instruments to measure irradiation in remote locations has become a serious concern, so this study model the irradiation by harmonic analysis. The evaluated analysis recognises the suitable harmonic equation for the cities, which would sustainably enhance energy usage. Time series analysis involves the correlation of Fourier technique to meteorological parameters such as irradiation and precipitation. This process’s application highlighted the predominant contribution of yearly harmonic in a productive way rather than the subsequent harmonics. This idea allows obtaining a time series function that estimates irradiation’s possible value for any day of the year in a geographical location. The interpretation of global irradiation’s spatial characteristics over twelve sites in India includes the estimation of amplitude, percentage variance, and phase angle of the harmonics. The first and second harmonic components contribute larger than 91% of the irradiation variance in studied locations. Statistical error metrics evaluate the developed harmonic equations’ performance based on ranking technique. Global Performance Indicator identifies the appropriate harmonic equation using scaled statistical metrics. The study found a mean bias error closer to zero, and a lower value of root mean square error indicate a close estimation to measured values. However, the mean absolute percentage error varies between 1.9491% (Chennai) and 22.2184% (Goa) specifies overestimation due to overcast and cloudy conditions.