In this paper, two aspects related to streetlight systems are considered. In the first part, the economic analysis of replacing existing HPS lamps with light-emitting diode (LED) and discrete LED lamps for street lighting is performed using actual data from Oman. The street lighting system inside Sultan Qaboos University is considered for the case study. The discounted payback period, which is calculated to study the practicability of implementing the system, is found to be 1.01 years, making the system financially appealing. Moreover, the estimated reduction of a carbon footprint shows that tonnes of CO2 emissions are reduced, which makes it environmentally attractive. The second part of the paper considers optimal sizing of PV/battery system for a new streetlight system with LED lamps. The life cycle cost analysis was performed and the related cost of energy generated per kWh is estimated as 0.097 $/kWh which proves the economic viability of the system to be implemented in Oman besides minimizing the CO2 emissions to zero.