Solar photovoltaic (PV) systems can provide reactive power support through their interfacing smart inverters. This reactive power exchange can provide effective voltage regulation at the inverter’s connection point and supplement the voltage regulation already offered by legacy voltage regulation devices, on-load tap changers and capacitor banks. Conservation voltage reduction (CVR), the intentional operation of the electrical system to provide customer voltages in the lower end of the acceptable range to reduce energy and demand, has recently gained significant research interest due to voltage regulation support by the increasing integration of PVs. This chapter discusses that CVR benefits can be significantly enhanced by considering the location, inverter capacity and number of PV systems, and presents an optimal PV placement method to enhance CVR benefits in integrated electricity and natural gas systems, where the electrical and natural gas networks are linked via gas-fired distributed generations and power-to-gas units. The chapter then introduces an optimal PV placement problem to minimize load consumptions and the network power losses while observing all operational constraints in the system. The location of PVs and capacity of PV inverters are decision variables. Through case studies using the modified IEEE 33-bus electricity and 7-node natural gas test system, the chapter demonstrates that optimally placed PVs lead to significant improvement in load consumption reductions compared to randomly placed PVs, and a higher number of PVs provides higher power loss reductions for CVR implementation.