With the accelerated low-carbon transformation of China's cultural and tourism industry and the increasing demand for refined energy management, energy storage technology is becoming a key support for large-scale tourism complexes to achieve green operations and enhance energy resilience.

A certain international holiday resort in Shenzhen integrates theme parks, high-end hotel clusters, convention centers, and commercial complexes. Its energy storage system needs to meet the high-reliability power supply demand of 7×24 hours. Meanwhile, the dense electrical equipment and highly mobile population within the park set extremely high requirements for the safety protection level of the energy storage system.

The owner plans to build a 2.5MW/15MWh vanadium flow battery energy storage system on the second underground floor, equipped with one PCS (Power Conversion System) with a capacity of 2.5MW. The output line of the PCS will be connected to the high-voltage switchgear through a transformer box and then paralleled to the 10kV plant power grid to complete the grid connection. According to the electricity price for agency purchase in Shenzhen in February 2025:

Based on the above table of electricity prices, it can be seen that the peak-valley price difference is 0.784 yuan per kWh, and the peak-valley price difference in July, August, and September is 1.041 yuan per kWh, indicating a significant opportunity for peak-valley arbitrage. The time-of-use electricity prices are shown in the figure below:

As shown in the above electricity consumption analysis, the peak period lasts for a total of 7 hours, divided into two time slots: 2 hours in the morning and 5 hours in the afternoon. There are 2 hours of flat rate periods before each peak period, and an 8-hour valley period in the early morning. The charging and discharging strategy is as follows:

The system charges for 7.5 hours and discharges for 6 hours each day, completing a total of 1.0 charge-discharge cycle per day. The system is fully charged during the valley period (0:00–7:30), discharges for 2 hours during the peak period from 10:00 to 12:00, and discharges for 4 hours during the peak period from 14:00 to 18:00.

To maximize the return on investment for investors and owners, the economic analysis of this project took into account the energy storage subsidy policies in Shenzhen. According to the "Several Measures for Accelerating the Development of the Electrochemical Energy Storage Industry in Shenzhen (Draft for Comments)," a subsidy of up to 30% of the investment amount, capped at 10 million yuan, is provided. According to the "Several Measures for Promoting the High-Quality Development of the Green and Low-Carbon Industry in Shenzhen (Draft for Comments)," a subsidy of up to 0.2 yuan per kWh based on the actual discharge volume is provided for a period of 3 years, with a maximum total subsidy of 3 million yuan per project.

In summary, the investment for this project is fully funded by the investor. The owner's share of the government subsidy is 50%, and the owner's share of the peak-valley price difference is 12%. The value-added tax rate for equipment is 13%, and the income tax rate is 25%. The annual operation and maintenance cost is calculated as 0.5% of the equipment cost, and the shutdown maintenance rate is calculated as 4%. The equipment for this project is depreciated over 20 years (design and construction costs are not included). Considering that the electrolyte recovery rate of the vanadium flow battery system can reach 70% at the end of its 20-year lifespan, the recovered funds will be counted as income in the final year.

The economic data of the project obtained through the NeLCOS® Energy Storage Calculator developed by ZH Energy are as follows: The equipment investment for this project is 34.33 million yuan. The total installed power is 2.5MW, and the installed capacity is 15MWh. The annual discharge volume is 5.256 million kWh. The system is designed for a service life of 20 years. The investment plan is full investment, with an internal rate of return (IRR) of 11.58%. It is expected that the capital investment will be recovered in 7.37 years. The total income for the owner over the 20-year service period is expected to be 13.97 million yuan, including 5 million yuan from government subsidies. The peak-valley price difference income over the 20-year service period is shared by the owner at 12% of the income, with an estimated total amount of 8.97 million yuan over 20 years and an average annual share of 448,700 yuan.

The calculation of government subsidy income is as follows: After deducting 30% of the service fee from the installed equipment subsidy, the remaining 70% is shared equally between the owner and the investor (i.e., each gets 35%). For the electricity reward part, the owner and the investor share equally.

1. According to the "Several Measures for Accelerating the Development of the Electrochemical Energy Storage Industry in Shenzhen (Draft for Comments)": 34.33 million yuan × 30% = 10.299 million yuan; 10 million yuan × 35% = 3.5 million yuan.

2. According to the "Several Measures for Promoting the High-Quality Development of the Green and Low-Carbon Industry in Shenzhen (Draft for Comments)": 5.256 million kWh × 0.2 yuan/kWh × 3 years = 3.15 million yuan; 3 million yuan × 50% = 1.5 million yuan.

The NeLCOS® Energy Storage Calculator, independently developed and operated by ZH Energy, can provide free calculations for energy storage customers and investors on the levelized cost of electricity storage, annual return on investment, and energy storage configuration plans. To access the calculator, visit the Zhonghe Energy official website (www.z-henergy.com) or scan the QR code for free use!

Product Series：

Vanadium Redox Flow Battery - Energy Storage System / BMS

Liquid Flow Battery - Non-Fluorinated Ion Exchange Membrane

LAB Series R&D Demonstration Equipment

NeLCOS® Energy Storage System Levelized Cost of Energy Calculator