The Cost and Benefit of a 10kW Photovoltaic Energy Storage System

The Cost and Benefit of a 10kW Photovoltaic Energy Storage System

Taking the 10kW energy storage power station in Guangzhou as an example, we learned from the Guangzhou Power Supply Bureau that residents can choose either tiered electricity prices or peak-valley electricity prices, and the cost of 10kw solar battery bank is mainly in the cost of purchase and replacement, basically no maintenance. In terms of grid-connected electricity sales, photovoltaic energy storage is prioritized for self-use, and there is no peak electricity price for power generation and electricity sales, and benchmark electricity prices for desulfurized coal are implemented (different from province to province). In addition, electricity consumption, electricity storage, and electricity sales settings need to be completed by hybrid inverters. Pure grid-connected inverters do not have this function.


So what are the costs and benefits of a photovoltaic system?

Let’s take a look:

1 Estimation of electricity consumption of Guangzhou residents: assuming that the electricity consumption of a single household is 650 degrees

Assume that 10kW photovoltaic energy storage is used to meet household electricity demand.

10kW system, 1100 hours of full power generation throughout the year, estimated power generation of 11000 kWh

Annual self-consumption electricity: 650 kWh/month × December = 7800 kWh

Annual electricity sales: 3,300 kWh, the price of electricity sold is 0.453 yuan/kWh, and the income from selling electricity is 1,494.9 yuan

Annual income: 6714.9 yuan


2 Cost of 10 kw lithium battery pack

If a low-cost lead-carbon battery is used for energy storage, the unit investment is 1200 yuan/kWh, the discharge depth is set to 70%, and the discharge efficiency is set to 0.94. To charge and discharge at 20 degrees, the battery capacity needs to be configured as:

12V 200Ah solar battery bank for house batteries are used in 4 strings and 3 and a total of 12 cells. The cost of the first battery investment is 36,480 yuan.

The discharge curve of the solar energy battery is as shown in the figure below (25°C). When the DOD is 70%, the number of cycles is about 4000. However, when the battery is lower than 0°C or higher than 40°C, its performance is greatly affected. Therefore, we estimate that the number of cycles is 3000, and it can be used for about 8 years.

The 10kw battery pack for house needs to be replaced 3 times during the 25-year service life cycle.

The 10kw battery bank for house recycling price is about 1.5 yuan/Ah, and the recycling income is about 200*1.5*4*3*2=7200 yuan

The total cost of the battery in 25 years is about 100,000 yuan

25 years electricity cost is about 0.5 yuan

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