Energy storage is a key technology to improve the reliability of the power system and promote the consumption of renewable energy. It is a technology that converts electrical energy that is not easy to store into mechanical energy, chemical energy and other forms and stores it for use when needed.
Residential energy storage refers to energy storage systems used for home users. Residential energy storage systems are usually installed in combination with residential photovoltaic systems to provide electrical energy to home users. During the day, the electric energy generated by photovoltaics is given priority to local loads. The excess energy is stored in the battery and can be selectively integrated into the power grid when there is still surplus electric energy. At night, when the photovoltaic system cannot generate electricity, the battery is discharged to provide electric energy for local loads use. Residential energy storage systems can improve the degree of self-use of residential photovoltaics, reduce users’ electricity bills, and ensure the stability of users’ electricity consumption in extreme weather and other conditions. For users in areas with high electricity prices, peak-to-valley price differences, or old power grids, purchasing residential storage systems is more economical, and residential users have the motivation to purchase residential battery storage systems. The single installed capacity of residential storage is small, and it mainly adopts the electrochemical energy storage route. Residential energy storage installed capacity is usually at the 10kWh level.
Residential battery storage is easy to be promoted with flexible installed capacity, mature industrial chain, easy mass production and promotion, and simple installation, operation and maintenance. The combination of residential energy storage and photovoltaics solves the problem that photovoltaics cannot be used at night and on rainy days, and reduces the pressure on the power grid caused by the large-scale use of new energy power. For residential users, residential battery storage can reduce electricity costs by increasing the proportion of self-consumption and participating in auxiliary services. At the same time, it can be used as an emergency backup power source when the power grid is mid-range due to major disasters and other factors, improving the reliability of Residential power supply; For the power grid, the rapid increase in the proportion of VRE (Volatile Renewable Energy) will further widen the difference between the power generation curve and the power consumption curve. The configuration of energy storage can transfer power over time to assist the power grid in balancing power generation capacity and power consumption need.
Residential battery storage is a form of energy storage with decentralized layout and nearby utilization. It can well adapt to decentralized power demand and resource distribution. The classification can include grid-connected residential storage systems and off-grid residential storage systems. Grid-connected residential battery storage systems can supply power to residential loads from the power grid or transmit power to the grid from residential photovoltaic storage systems. Off-grid residential battery storage systems have no electrical connection to the grid and are suitable for remote areas without grids such as isolated islands or archipelago countries. With the power supply unstable, the demand for residential battery storage is very strong. In areas covered by the power grid, under the background of high electricity prices and energy security needs, residential battery storage installations can significantly save users’ electricity bills, and the ROI of installed capacity have gradually become more prominent, driving the rapid explosion of the residential battery storage market.
For residential users that have already installed photovoltaic power generation systems, the original system can also be transformed by installing an energy storage system. From a professional perspective, the grid-connected residential battery storage system modified by old users is called a coupled residential battery storage system, also known as an AC-renovated residential storage system. The system generally consists of photovoltaic modules, grid-connected inverters, lithium batteries, and AC-coupled residential battery storage systems. It consists of energy storage inverter, smart meter, CT, power grid, grid-connected load and off-grid load. This system can convert photovoltaic power into AC power through the grid-connected inverter, and then convert the excess power into DC power through the AC-coupled energy storage inverter and store it in the battery. The working principle of this residential battery storage system is that during the day, photovoltaic power generation first supplies the load, then charges the battery, and finally the excess power can be connected to the grid; at night, the battery discharges to supply the load, and the shortfall is supplemented by the grid; when the grid fails, the lithium battery only supplies power to the homes only. In addition, the system also supports users to set their own charging and discharging times to meet users’ power needs.
There is also a hybrid residential battery storage system, which is currently the mainstream in the market and is also favored by users. The hybrid residential battery storage system consists of photovoltaic modules, lithium batteries, hybrid inverters, smart meters, CT, power grid, grid-connected loads and off-grid loads. This system can realize photovoltaic charging of batteries directly through DC-DC conversion, and can also realize bidirectional DC-AC conversion for charging and discharging of batteries. Its working principle is that during the day, photovoltaic power generation first supplies the load, then charges the battery, and finally the excess power can be connected to the grid; at night, the battery discharges to supply the load, and the shortfall is supplemented by the grid; when the power grid fails, photovoltaic power generation and lithium batteries only supply power to the off-grid load, the grid-connected load cannot be used. In addition, the system also supports users to set their own charging and discharging times to meet users’ power needs. This system can significantly reduce initial installation time and costs.
POWEROAD has developed a line of residential energy storage batteries, which compatible with mainstreaming inverters to fulfill demands for various scenarios. Contact us for learning more about the tailored battery solutions!