Global deployment of solar photovoltaics: Its opportunities and challenges

With the focus on environmental sustainability and energy security, policy makers and electric utility planners are looking at renewable energy both as supplements and alternatives. But such generation sources have their own challenges — primarily high variability, especially for solar and wind. This paper highlights the challenges and opportunities in grid integration of large-scale solar photovoltaic (PV) plants. Total global grid-connected PV installation exceeded 177 GW in 2014 with Germany, China, the U.S., Italy and Japan leading the way. While MW-scale solar power plants have gained significant attention as a very clean form of electricity replacing greenhouse gas-emitting fossil fuel power plants, an array of challenges regarding network operation arises from the inherent variability in output. This challenge is exacerbated when there is a high penetration of PV both in the distribution circuit and the high voltage transmission network. Potential concerns for the traditional distribution network include reverse power flow, overvoltage and voltage fluctuations, effects on voltage control devices, etc. At the transmission level the fluctuation in PV output can cause voltage stability problems. This paper addresses the growth of the PV market in different regions and briefly discusses the required interplay among external factors (like inverter functionalities, storage, demand response and revised grid standards) to provide an efficient operational strategy in the context of high PV penetrations.