Whether the hottest photovoltaic energy storage is

2022-07-31
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Whether photovoltaic + energy storage is economically feasible depends on the electricity price structure

recently, the residential solar + energy storage market has attracted extensive attention. With the continuous emergence of new low-cost products and the application of time-sharing pricing and demand tariff structure by power companies, the overall economy of solar PV + energy storage system is continuously improving. However, what kind of market environment do we ultimately need to achieve the extensive deployment of solar photosynthetic + energy storage systems? This has always been a problem of data correction. In order to better understand the evolution of the market, the Rocky Mountain Institute conducted research on the services and values that battery energy storage can provide. In addition, we have also conducted further research with the National Renewable Energy Laboratory (NREL) to test the cost and value of solar PV + energy storage system

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as early as april2015, the Rocky Mountain Institute and its partners including globalx and Homer energy released a research report entitled "economic analysis of load shedding". The report investigates how solar + battery systems connected to electricity will compete with traditional electricity services. The results show that by 2030, the declining system cost and the rising retail price of electricity will make the solar + battery system connected to electricity more economical and will become the first choice for many American consumers. In addition, the solar + battery system can provide users with other important values. For example, it serves as a backup power supply for critical loads in case of power failure, and saves costs by reducing peak demand and transferring power consumption time. However, the Rockies research did not specify the precise cost of energy storage at that time

to decompose the installation cost of solar PV + energy storage system, the Rocky Mountain Institute and the National Renewable Energy Laboratory first analyzed the data of various existing studies including Lazard and GTM, as well as our accumulated experience in the innovation center project of the Rocky Mountain Institute

in order to analyze the cost of each part of the solar PV + energy storage system installed in the first quarter of 2016 and the total cost of the system, we used the bottom-up cost model of each part and system level of the National Renewable Energy Laboratory to analyze the independent solar PV system. Our methodology includes the calculation of all component costs and project development costs incurred in the installation of residential systems, and simulates the cash purchase price of such systems without considering the preferential policy of investment tax relief (ITC)

we focus on two main applications: one is called small battery, 3 kW/6 kwh, and the other is called large battery, 5 kW/20 kwh. In each case, we tested the sensitivity of two types of variables: DC or AC coupling configuration, and renovation projects or new installation projects. The difference between DC and AC coupling configuration determines whether the battery directly stores the power generated by the solar PV panel, or first converts it into AC, thus allowing the PV panel and electricity to be charged at the same time. The small battery case is designed for consumers' own power consumption, including reducing peak demand and transferring power consumption time, while the large battery case is designed as a backup power supply for large energy demand to meet power demand in case of power failure

we found that the benchmark price of small-scale battery cases using 5.6kw solar PV panels and 3kw/6kwh lithium-ion batteries is about twice that of a single 5.6kw solar PV system connected to electricity (see Figure 1 for details). For the newly installed solar PV + energy storage system, the price of DC system (27703 US dollars) is 1865 US dollars lower than that of AC system (29568 US dollars). The price premium of AC system is mainly due to the hardware and labor costs caused by the additional parallel converters required for AC configuration. 2. On a solid foundation or workbench, however, when comparing AC and DC systems, the installation price is not the only consideration: AC systems are more efficient in the application of photovoltaic energy generation and use, while DC systems are more efficient in the application of photovoltaic energy storage and storage

Figure 1: residential solar PV + energy storage system, total installation cost and price composition model of small battery case (2016 US dollar current price)

in order to compare with the small battery system shown in the figure above, we also analyzed the large battery system used to supply standby power for a long time in case of power failure. The large-scale system uses a 5.6kw solar photovoltaic group and a large capacity 5KW/20kwh lithium-ion battery (see Figure 2). The price of large DC system is 45237 USD, which is 63% higher than that of small DC system. The price of the large AC system is $47171, which is 60% higher than that of the small system. Although the cost is higher, under the same conditions of other factors, the time that a large system can supply critical load for a family is about four times that of a small system

Figure 2: residential solar PV + energy storage system, total installation cost and price composition model of small battery compared with large battery case (current price in 2016 dollars)

price composition breakdown shows that hardware cost only accounts for half of the total price of small battery system and about 60% of the total price of large battery system. Other costs depend on the installation location of the system: local costs, administrative approval, liaison, measurement and other processes, as well as local fire protection 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 the solar PV + energy storage project connected to electricity include the electricity price, subsidies, auxiliary service pricing, etc. of local power companies. Among them, the electricity price structure of power companies (for example, whether to use peak demand electricity price, time of use electricity price and other policies and 100000 square meters of outdoor exhibition area) is often the key factor to determine whether adding energy storage function to solar photovoltaic system is economically feasible

although the cost of solar PV + energy storage system continues to decline, the soft costs related to administrative approval and management obstacles still make them relatively high for many residential users. However, with the increasing familiarity of power companies and approval authorities with residential energy storage systems, we expect the residential energy storage market to grow faster and faster in the United States

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