The home battery storage+energy storage market is widely concerned. With the continuous emergence of new low-cost products and the application of time-sharing pricing and electricity demand rate structure by power companies, the overall economy of solar PV+energy storage system is constantly improving. However, in order to achieve the widespread deployment of solar photosynthesis+energy storage system, what is the cost of solar battery storage system?
A major problem in analyzing the cost of each part of the solar PV+energy storage system and the total cost of the system is to select an appropriate measurement standard. Unlike single solar PV, energy storage systems lack widely accepted metrics, such as cost per watt of installed capacity or levelized energy cost. The cost of solar photovoltaic battery energy storage will vary with the total energy capacity of the system (expressed in USD/kWh) and the rate of charging or discharging (expressed in USD/kW). Some consumers prefer to use the long-term discharge function of the system, while others may have higher peak demand and pay more attention to the power of energy storage (kW) rather than energy capacity (kWh). Due to different family preferences and load characteristics, using a single metric will artificially interfere with the cost published by the system, and it is difficult to compare the cost differences of different systems. Therefore, we used the total installation price as the main measurement of the study, rather than the standardized standard based on the system size.
When applying these methods, we mainly focus on two main cases: one is called a small battery, 48v lithium solar battery 3 kW/6 kWh, and the other is called a large battery, 5 kW 20 kWh. In each case, we tested the sensitivity of two types of variables: DC or AC coupling configuration, and reconstruction projects or new installation projects. The difference between DC and AC coupling configurations determines whether the battery directly stores the power generated by the solar photovoltaic panel or first converts it into AC power to allow the photovoltaic panel and the grid to charge at the same time. Small battery cases are designed for consumers' own power consumption, including reducing peak demand and transferring power consumption time, while large battery cases are used as backup power for large energy demand to meet power demand in case of power failure.
We found that the benchmark price of a small battery case using 5.6 kilowatt solar photovoltaic panels and 3 kilowatt/6 kilowatt hour lithium-ion batteries is about twice that of a single 5.6 kilowatt solar battery photovoltaic system connected to the grid (see Figure 1 for details). For the newly installed solar PV+energy storage system, the price of DC system (US $27703) is US $1865 lower than that of AC system (US $29568). The price premium of AC system is mainly due to the hardware and labor costs caused by additional grid connected converters required for AC configuration. However, when comparing AC and DC systems, the installation price is not the only factor to consider: AC systems are more efficient in the application of instant photovoltaic energy, while DC systems are more efficient in the application of photovoltaic energy storage.
What is the solar battery storage system cost? Compared with the small battery system, we also analyzed the large battery system used to supply standby power for a long time in case of power failure. The large system uses 5.6kw solar photovoltaic cell and 5kw/20kwh lithium-ion battery with large capacity (see Figure 2). The price of large DC system is $45237, 63% higher than that of small DC system. The price of large AC system is 47171 US dollars, 60% higher than that of small system. Although the cost is higher, under the same conditions of other factors, the time for a large system to supply critical load for a household is about 4 times that for a small system.
The breakdown of price composition shows that the hardware cost only accounts for half of the total price of small lithium solar battery 200ah systems and about 60% of the total price of large battery systems. Other costs depend on the installation location of the system: local costs, administrative approval, networking, metering and other processes, as well as local fire standards vary greatly, which will not only affect the project cost, but also affect the project schedule. The variables that have the greatest impact on the financial feasibility of solar PV+energy storage projects connected to the power grid include electricity prices, subsidies, auxiliary service pricing, etc. of local power companies. Among them, the power grid company's electricity price structure (for example, whether to use peak demand electricity price, time-sharing electricity price and other policies) is often the key factor determining whether it is economically feasible to add energy storage functions to the solar photovoltaic system