Solar energy from Negev desert, Israel: Assessment of power fluctuations for future PV fleet

Abstract

Power output fluctuations have a potentially negative effect on utility grid stability, especially in isolated power systems such as that of Israel. Thus for the successful large scale application of photovoltaic power (PV) in an isolated system it is of particular importance to have a proper selection of photovoltaic sites together with an appropriate distribution of installed power.The Negev desert in Israel is an ideal location for utility scale PV plants, where the average annual global horizontal radiation is above 2000 [kWh∗m−2∗year−1]. In spite of the 10% goal of renewably energy production by year 2020, in 2013 less than 1% of Israel's electric energy needs are supplied by PV and now is the best time to propose a proper spatial distribution of PV fleet in Negev that will limit the extreme fluctuations originated from the fleet without significantly reducing the utilized solar energy.This paper presents a method of comparing different PV development scenarios by ranking them according to expected power fluctuations.The irradiation fluctuation rank formulated in this paper was calculated using data of global irradiation measured during one and a half year with a 1minute sampling time on seven sites in Israel's Negev desert. This rank values were compared for a large number of different possible geographical distributions of PV power plants.Results show that the rank decreases with distribution of the same PV power over an increasing number of sites. The rank shows similar trends for the period of a year as well as for different seasons. Allocating PV power with different weights between a fixed number of sites influences the number of extreme power fluctuations. The PV fleet configuration with the minimum rank value shows the minimum number of extreme power fluctuations that will affect system frequency.