Policies and economic efficiency of China's distributed photovoltaic and energy storage industry

Storage energy is an effective means and key technology for overcoming the intermittency and instability of photovoltaic (PV) power. In the early stages of the PV and energy storage (ES) industries, economic efficiency is highly dependent on industrial policies. This study analyzes the key points of policies on technical support, management drive, and financial support. Focusing on the efficiency of PV power and the power load of users, including households and enterprises, in Shanghai City over 24 h in 2016, this study analyzes the costs, benefits, internal rates of return, and investment recovery periods of distributed PV (DPV) and ES systems in the current policy context. This study also discusses the influences of various policy variables, including the ES battery capacity, the peak-valley price ratio, feed-in tariffs for DPV, and the ratio of grid-connected surplus PV power, on economic efficiency. The results show that in China's current policy context, both household and enterprise users of PV power would gain some economic benefits if PV systems were fitted with aqueous sodium-ion batteries of an appropriate capacity. Finally, this study offers some additional government policy suggestions.