For factories, electricity costs are the third largest fixed cost after raw materials and labor. Especially for high-energy-consuming factories, the monthly electricity bill is often several hundred thousand yuan, which adds up to a considerable expense over the years. With the maturity of photovoltaic technology and the decline in costs, more and more factories have chosen to install photovoltaic power stations on their roofs and factory grounds in 2026. This not only allows self-generation and self-consumption to reduce electricity costs, but also achieves green compliance and even additional profits. However, many factory owners have a question in mind: how much electricity cost can be saved annually by installing photovoltaics? Is this investment worthwhile? Today, using real data, accurate formulas, and combined with the latest market conditions in 2026, we will calculate a clear income account for everyone, refusing empty talk and focusing on practical calculation logic.
Core Premises: Clarify 2 Key Points First for Accurate Calculation
The amount of electricity cost saved by factory photovoltaics depends on two core factors: first, the actual power generation of the photovoltaic power station, and second, the factory's own electricity cost (peak-valley tariff differences, self-consumption rate). The final amount of electricity cost saved varies greatly depending on the region, factory building, and electricity consumption scale, but the calculation logic is completely universal. First, let's clarify two basic premises to avoid calculation deviations:
1. Power Station Scale: Factory photovoltaics are mostly distributed power stations, and the scale is usually calculated in "kilowatts (kW)" or "megawatts (MW)", where 1MW = 1000kW. The common scale ranges from 100kW (small factories) to 10MW (large industrial parks). The roof area determines the maximum installed capacity (a conventional 100kW requires a roof area of about 800-1000 square meters);
2. Core Parameters: In 2026, N-type modules have become the mainstream with a conversion efficiency of more than 23%, and the comprehensive system efficiency is about 0.7-0.8 (which can reach more than 0.8 for industrial and commercial standard design); the annual equivalent full-load hours vary in different regions (1600-2000h in the northwest, 1100-1400h in the east China, 1000-1200h in the south China), which directly affects power generation; industrial and commercial electricity prices are divided into three segments: peak, flat, and valley. The peak segment is 1.0-1.5 yuan/kWh, the flat segment is 0.7-0.9 yuan/kWh, and the valley segment is 0.3-0.4 yuan/kWh. The higher the self-consumption rate, the more electricity costs are saved.
Step 1: Calculate Power Generation First — How Much Electricity Can Photovoltaics Generate Annually? (Accurate Formulas + Cases)
Power generation is the foundation of saving electricity costs; without power generation, there is no room for saving electricity costs. Many factory owners are easily misled by "theoretical power generation" and ignore actual losses. Here, we provide two calculation methods for you: novices can directly apply the simplified formula, and professionals can refer to the accurate formula.
Simplified Calculation Formula (Preferred for Novices, Error ≤ 10%)
Actual Annual Power Generation (kWh) = Installed Capacity (kW) × Local Annual Equivalent Full-Load Hours (h) × Comprehensive Efficiency Coefficient (0.7-0.8)
Core Explanation: The comprehensive efficiency coefficient includes all actual losses such as module attenuation, temperature loss, line loss, and equipment shutdown. Due to standard design, industrial and commercial power stations can take a value of 0.75-0.8, while household photovoltaics can take a value of 0.7-0.75 to avoid overestimating power generation.
Accurate Calculation Formula (Professional Level, Suitable for Project Approval)
Actual Annual Power Generation (kWh) = Installed Capacity (kW) × Local Annual Equivalent Full-Load Hours (h) × System Efficiency (0.8-0.85) × Temperature Correction Coefficient (0.86-0.95) × Operation Efficiency (0.90-0.95)
Supplementary Note: The temperature correction coefficient is easily overlooked. In summer, the actual temperature of modules can reach 60-70℃, which will reduce power generation efficiency by 10%-15%. The temperature coefficient of conventional monocrystalline modules is 0.004/℃, which can be adjusted according to the maximum summer temperature in the local area.
Real Case Calculation (Taking a 100kW Power Station in East China as an Example)
Assumptions: A machinery factory in East China with an installed capacity of 100kW (color steel tile roof, requiring about 800 square meters), local annual equivalent full-load hours of 1300h, comprehensive efficiency coefficient of 0.8, and 2026 N-type module configuration.
Actual Annual Power Generation = 100kW × 1300h × 0.8 = 104,000 kWh (104,000 kWh)
Supplementary Note: For a 100kW power station in the northwest region (full-load hours of 1800h), the actual annual power generation = 100 × 1800 × 0.8 = 144,000 kWh (144,000 kWh); for a 100kW power station in the south China region (full-load hours of 1100h), the actual annual power generation = 100 × 1100 × 0.8 = 88,000 kWh (88,000 kWh).
Step 2: Calculate Electricity Cost Savings — How Much Can Be Saved Annually? (Scenario-Based Calculation)
The core logic of factory photovoltaic electricity cost savings is "self-generation and self-consumption, surplus electricity fed into the grid": the electricity generated by oneself is used by oneself, without spending money on grid electricity (the saved amount is pure profit); the surplus electricity is sold to the grid for additional income. The amount of electricity cost saved = self-consumed power generation × factory electricity unit price - surplus electricity grid-connected income (if there is surplus electricity). Here, we calculate three common scenarios to cover factories of different scales.
Scenario 1: Small-Scale Factory (100kW Power Station, 80% Self-Consumption Rate, East China)
Known: Annual power generation of 104,000 kWh, self-consumption rate of 80% (i.e., 83,200 kWh self-consumed, 20,800 kWh surplus electricity); factory electricity adopts the average industrial and commercial electricity price in East China: peak segment 1.1 yuan/kWh, flat segment 0.8 yuan/kWh, valley segment 0.35 yuan/kWh, comprehensive electricity unit price 0.85 yuan/kWh; surplus electricity grid-connected price 0.38 yuan/kWh (2026 national unified desulfurized coal benchmark electricity price).
1. Self-Consumption Electricity Cost Savings: 83,200 kWh × 0.85 yuan/kWh = 70,720 yuan
2. Surplus Electricity Grid-Connected Income: 20,800 kWh × 0.38 yuan/kWh = 7,904 yuan
3. Total Annual Income (Savings + Earnings): 70,720 + 7,904 ≈ 78,624 yuan
Conclusion: A 100kW power station can save more than 70,000 yuan in electricity costs annually alone, and with surplus electricity income, the total annual income is nearly 80,000 yuan.
Scenario 2: Medium-Scale Factory (1MW Power Station, 70% Self-Consumption Rate, Anhui Region)
Known: 1MW = 1000kW, annual equivalent full-load hours in Anhui region of 1200h, comprehensive efficiency of 0.8, annual power generation = 1000 × 1200 × 0.8 = 960,000 kWh; self-consumption rate of 70% (672,000 kWh self-consumed, 288,000 kWh surplus electricity); referring to Anhui industrial and commercial electricity prices in March 2026, the non-time-of-use electricity price for 1-10 kV is 0.6101 yuan/kWh, peak segment 0.9789 yuan/kWh, comprehensive electricity unit price 0.75 yuan/kWh; surplus electricity grid-connected price 0.38 yuan/kWh.
1. Self-Consumption Electricity Cost Savings: 672,000 kWh × 0.75 yuan/kWh = 504,000 yuan
2. Surplus Electricity Grid-Connected Income: 288,000 kWh × 0.38 yuan/kWh = 109,440 yuan
3. Total Annual Income (Savings + Earnings): 504,000 + 109,440 ≈ 613,440 yuan
Supplementary Note: This scale of power station has a color steel tile roof. The total investment in 2026 is about 2.3 million yuan, with a payback period of about 4-5 years. The total net income during the 25-year full life cycle can reach more than 12 million yuan, making it a stable green investment.
Scenario 3: Large-Scale Factory (5MW Power Station, 90% Self-Consumption Rate, High-Energy-Consuming Industry)
Known: 5MW = 5000kW, annual equivalent full-load hours in East China of 1300h, comprehensive efficiency of 0.82, annual power generation = 5000 × 1300 × 0.82 = 5,330,000 kWh; self-consumption rate of 90% (4,797,000 kWh self-consumed, 533,000 kWh surplus electricity); high-energy-consuming factories have higher electricity unit prices, with a comprehensive electricity price of 0.95 yuan/kWh, and surplus electricity grid-connected price of 0.38 yuan/kWh.
1. Self-Consumption Electricity Cost Savings: 4,797,000 kWh × 0.95 yuan/kWh = 4,557,150 yuan
2. Surplus Electricity Grid-Connected Income: 533,000 kWh × 0.38 yuan/kWh = 202,540 yuan
3. Total Annual Income (Savings + Earnings): 4,557,150 + 202,540 ≈ 4,759,690 yuan
Conclusion: Installing photovoltaics in large-scale high-energy-consuming factories can save nearly 4.8 million yuan in electricity costs annually, which is equivalent to an additional considerable net profit. At the same time, it can meet the compliance requirements of green factories and cope with the pressure of carbon tariffs.
Real Factory Case Evidence: Not Theory, but Achieved Income
Xinghua Jiajie Plastic Products Co., Ltd., as a major electricity consumer, has an annual electricity consumption of about 1.8 million kWh and an electricity bill of about 1.4 million yuan. In 2025, the enterprise installed a 690kW photovoltaic power station using its 6,000 square meter factory roof, with an annual power generation of about 760,000 kWh. The green electricity price is only half of the industrial electricity price, saving about 300,000 yuan in electricity costs annually. The saved funds are all used to introduce new equipment and improve product competitiveness.
There are many similar cases. Whether it is a food factory, a machinery factory, or a factory in a continuous industrial park, as long as there is available roof space and stable electricity demand, installing photovoltaics can achieve tangible electricity cost savings. Moreover, with the popularization of N-type modules in 2026, the power generation has increased by 10%-15% compared with previous years, and the effect of saving electricity costs is more obvious.
Key Reminder: 3 Factors Affecting Electricity Cost Savings, Don't Ignore!
1. Self-Consumption Rate: This is the core factor affecting electricity cost savings! The higher the self-consumption rate, the more money saved (using one kWh of electricity by oneself saves one kWh of money; selling to the grid only earns a meager grid-connected price). It is recommended that factories give priority to ensuring the self-consumption of photovoltaic power to avoid waste;
2. Roof Type: The investment cost of color steel tile roofs is about 320,000 yuan/MW lower than that of cement roofs. In addition, the construction is fast and the loss is small, which can put into production and generate income faster, indirectly increasing the annual electricity cost savings;
3. Operation and Maintenance Level: The service life of photovoltaic power stations is as long as 25 years. Daily cleaning and inspection can reduce power generation losses. If the operation and maintenance are in place, the comprehensive efficiency can be maintained above 0.8, generating 5%-10% more electricity annually and saving more electricity costs.
Conclusion: Installing Photovoltaics in Factories is a Profitable Deal
In summary, the amount of electricity cost saved by factories installing photovoltaics is about 70,000-100,000 yuan per year for small-scale factories (100kW), 500,000-700,000 yuan per year for medium-scale factories (1MW), and 4-6 million yuan per year for large-scale factories (5MW and above). The specific amount can be adjusted according to the own installed capacity, local light conditions, and electricity unit price.
In 2026, although photovoltaic subsidies have been fully withdrawn, the peak-valley price difference for industrial and commercial use has further expanded. Coupled with the improvement of N-type module efficiency and the stability of investment costs, the payback period for factories installing photovoltaics has been shortened to 4-6 years. In the subsequent 20 years or so, "zero-cost electricity + additional income" can be achieved. It not only reduces costs, but also achieves compliance and environmental protection. For factories with stable electricity demand, it is undoubtedly the best energy choice at present.
If you want to accurately calculate how much electricity cost your factory can save annually by installing photovoltaics, you can provide the factory roof area, location, and average monthly electricity bill, and we can give you a customized calculation result to help you quickly judge whether it is worth investing.
