Design and operation optimization of city-level off-grid hydro–photovoltaic complementary system

Abstract

Increasing attentions have been paid on the design and operation optimization of hydro-photovoltaic complementary systems due to the inherent uncertainty associated withthe solar energy. However, studies mainly focused on the household or community integrated power system while the city-level off-grid systems remained less explored. That was because both the large scale of the studied area and the complex factors associated with the city attached difficulties to the problems. This paper proposed an off-grid PV-hydro hybrid optimization model for the cities which were located nearby sufficient water resources based on Geographic Information System. The proposed model can guarantee the electricity demand with less economic cost and less storage facilities by taking full advantage of water resources. Firstly, the optimization-based economic analysis considering PV capital cost and hydroelectricity price was proposed to determine whether to install PV panels and the optimal size if install. Then, we set six scenarios to identify the relationship between the electricity consumption structure and the optimal PV scale due to the structure transformation according to the current energy policies. Finally, the detailed optimal power generation plan in typically weather conditions during operation period was analyzed. Results indicated that: (1) The city level off-grid PV-hydro complementary system was feasible according to the studied case. (2) The critical PV panel capital cost was 920 $/kW when the hydroelectricity price was 5¢/kW·h, and there was a linear relationship between these two parameters. (3) Optimal PV size was influenced by electricity consumption structure and peak month type, and the current structure transformation policy was beneficial for the PV-hydro systems. (4) The power generation plan varied a lot in different weather conditions and the detailed operation plan could be obtained in this paper.