The optimum tilt angle of PV array in Jerusalem is 25 deg. This optimum is for unlimited space available for PV array and for case when all electricity generated by PV is used by energy consumer. This publication goes further in the economic optimization analyzing case with limited area for installation of PV array. This limit requires considerations of spacing of PV panels to avoid shading of other rows. Spacing influences size of the PV array, while the unit cost of the PV installation depends on size.
The optimum solution for such case is 0 degree tilt angle, which means horizontal PV array, without any spacing. The publication analysis also case of constant unit cost of PV installation. In such case the optimum tilt angle for Jerusalem is 15 degrees and 130% spacing. Lower unit cost justifies smaller spacing. Four parameters are applied for optimization: return of investment (ROI), IRR, investment cost and NPV. This work introduces methodology for optimization of tilt angle and spacing of PV array in case of limited area. It also contains large volume of useful data and may be helpful for other works related to solar energy.