Climatic zoning and per capita demand forecast of Iran using degree-day method

ABSTRACT In order to achieve a more accurate prediction of future electrical energy consumption, the present research considers a long-term study of the climatic conditions of Iran for the top 82 most densely populated cities. For each city, heating degree-days (HDD) and cooling degree-days (CDD), precipitation, climatic zones classification, and an average temperature of coldest and warmest months are used as measures for the study. Subsequently, for the four most densely cities, the climate change during the past 60 years (1959–2018) has been investigated. Results show that CDD values for all cities have increased gradually in the same period, while HDD values have decreased. According to linear interpolation, average daily CDD 24°C in the year 2025 for Tehran is estimated as 1.903 (694.595 yearly). Furthermore, based on multiple linear regression analysis, the PCD for Tehran, Mashhad, Shiraz, Tabriz, Isfahan, and Kermanshah will change by 0.5%, 2.3%, 4.7%, 1.9%, 3.4% and −5.3% by the year 2030, respectively. It is also worth mentioning that the precipitation and Humidity have an inverse relation with PCD. Also, the effect of base temperature on CDD and HDD showed that only one-degree change in the base temperature could cause a significant change in CDD and HDD.