# A Review of Distribution Grid Consumption Strategies Containing Distributed Photovoltaics
## 3 Distribution Grid Consumption Strategy with Distributed PV
### Optimization of Distribution Grid Energy Storage with Distributed Photovoltaics
#### 3.2.1 Distributed PV Energy Storage Methods  
The distributed photovoltaic energy storage method refers to the combination of a photovoltaic power generation system and energy storage equipment to achieve optimal management of the power system and stable power supply. The distributed photovoltaic energy storage system access location is flexible, mainly in the medium- and low-voltage distribution network, microgrid, and user excess power into the power supply network. Reasonable planning of distributed energy storage, not only through the \"peak shaving to fill in the valley\", plays a role in reducing the capacity of the distribution network but also in making up for the distributed randomness of the grid security and economic operation of the impact. An energy storage control flow based on solar photovoltaic power generation control is shown in Figure 8[53]. The study of distributed PV energy storage systems mainly focuses on the above methods. Table 2 is a comparison of the advantages and disadvantages of several common distributed PV energy storage methods. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Energy Storage Method** & **Advantages** & **Drawbacks** \\ \hline \multirow{6}{*}{**Lithium-ion battery energy storage systems**[54] & High energy density, large energy stored per unit volume, long cycle life, can be charged and discharged many times, small self-discharge rate, no self-discharge phenomenon, no memory effect, can be charged at any time, green and environmentally friendly, does not contain lead, mercury, and other harmful substances.**} & The production cost is slightly higher; although the energy density of lithium-ion batteries is high, its performance will be reduced in high-temperature environments. \\  & First start-up time (\(<\)15 min), high energy and power density, black start capability, large energy storage capacity, low cost, long life, safety, and environmental protection. & Energy storage density is relatively low; energy storage efficiency is low, generally around 70\%; energy storage equipment is large and needs to occupy more space. \\ \hline \multirow{6}{*}{**Supercapacitor energy storage system**[56] & Fast charging speed, long discharge time, small size and lightweight, easy to install and transport, long life, can be used hundreds of thousands of times, high power density, can provide high power output. & Energy storage density is relatively low; energy storage efficiency is low, generally around 70\%; energy storage equipment is large and needs to occupy more space. \\ \hline \multirow{6}{*}{**Liquid-flow battery energy storage system**[57] & Ultra-long cycle life, high safety and stability, green, can be deeply discharged. & Batteries are too large, ambient temperature requirements are too high, and more expensive and complex systems. \\ \hline \multirow{6}{*}{**Hydrogen storage systems**[58] & Hydrogen storage is clean, efficient, and flexible in production; high density and large storage scale; small cost, which can effectively improve energy utilization. & Low energy conversion efficiency, high investment costs, and higher energy losses than other commonly used energy storage technologies. \\ \hline \multirow{2}{*}{**Pumped storage systems**[59; 60] & Mature and reliable technology, large energy storage capacity, strong regulation capability, strong economy, long life cycle. & High construction costs, geographic constraints, ecological impacts, and dependence on water resources. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of advantages and disadvantages of common distributed PV energy storage methods. Figure 8: An energy storage control process based on solar photovoltaic power generation control. The current research on energy storage technology is mainly divided into the following directions.