At present, there are roughly six profit methods for industrial and commercial energy storage: peak and valley arbitrage, energy time shifting, demand management, demand side response, power spot market transactions, and power ancillary services.

The above six profit methods are mutually exclusive, that is, you cannot obtain two kinds of profits at the same time.

Taking a 6MWh industrial and commercial energy storage project in Zhejiang Province as an example, the six income sources and income situation of industrial and commercial energy storage under the current policy conditions were calculated.

Detailed profit calculations for each item are as follows.

1. Basic assumptions of typical industrial and commercial energy storage projects

Zhejiang Province has built a new 3MW/6MWh user-side energy storage project. The voltage is boosted to 10kV and connected to the factory bus. The factory has a stable load during the day and can fully absorb energy storage and discharge, and the transformer capacity meets the energy storage charging needs.

Two charges and two discharges: Considering factory breaks and equipment maintenance, the energy storage equipment is operated for 300 days a year, with two charges and two discharges every day. The first time is charging at valley time 22:00-24:00, and the battery is discharged at peak period 9:00-11:00 the next day; the second time is charging at valley time 11:00-13:00, and the battery is discharged at peak period 19:00 -Discharge at 21:00.

Peak-to-valley price difference: Taking general industrial and commercial electricity in Zhejiang as an example in March 2023, the peak electricity price is 1.4085 yuan/kWh, the peak electricity price is 1.0463 yuan/kWh, and the off-peak electricity price is 0.4266 yuan/kWh.

Basic assumptions: investment cost is 1.8 yuan/Wh, the total investment is 10.8 million yuan, of which 70% is a bank loan, the loan interest rate is 4.65%, DOD is 90%, charge and discharge efficiency is 92%, and energy storage life is 10 years.

2. Peak and valley arbitrage profit calculation

Industrial and commercial users can charge energy storage batteries at cheaper off-peak electricity prices when electricity prices are low. When electricity prices peak, the energy storage batteries supply power to the load, realizing the transfer of peak loads and obtaining income from peak and valley electricity prices.

For a typical industrial and commercial energy storage project in Zhejiang Province, based on the calculation of a charge and discharge depth of 90%, a charge and discharge efficiency of 92%, an operation of 300 days a year, and two charges and discharges a day, the total income from peak and valley arbitrage in one year is 1.6732 million yuan.

Among the grid electricity purchase prices in March 2023, the peak-to-valley electricity price difference in 23 provinces and regions exceeded 0.7 yuan/kWh, which is higher than the break-even point for industrial and commercial energy storage for peak-to-valley arbitrage. Among them, the peak-to-valley price difference in Zhejiang is the highest in the country, with a price of 1.3258 yuan/degree, which is conducive to peak and valley arbitrage of industrial and commercial energy storage.

When only considering peak and valley arbitrage income, investing in a 3MW/6MWh energy storage system project with a life span of 10 years in Zhejiang Province, when the peak/peak/valley electricity price difference per unit is 0.9819/0.6197 yuan, the investment cost is 1.8 yuan/Wh. , IRR can reach 9.36%. Calculated at 70% for bank loans, the investment cost is expected to be recovered in 5.47 years, which is economically feasible.

As the peak-to-trough price gap continues to widen across the country and energy storage investment costs continue to decline, the IRR is expected to increase to more than 20%, and the economics of industrial and commercial energy storage become increasingly obvious.