Photovoltaic Power: A Comprehensive Guide from Principles to Applications

In today's energy transition, photovoltaic (PV) technology is undoubtedly a star that attracts much attention. From the widespread application of solar panels to the rise of photovoltaic power plants, the PV industry is changing our energy landscape at an astonishing speed. But do you truly understand the principles behind PV technology? What is its working mechanism? What are its application scenarios? What challenges and opportunities does it face? Today, the New Energy Intelligence Station brings you the most practical core knowledge points - from project filing to system design, from cost calculation to income accounting, a comprehensive analysis. If you find it valuable, please like and follow, and share with more industry peers!

I. Technical Principles

1. Photovoltaic Effect: The core principle of industrial and commercial photovoltaic power plants is the photovoltaic effect, which is that when sunlight shines on solar panels, the semiconductor material absorbs photon energy, generating electron-hole pairs, thus generating direct current.

2. System Composition: Industrial and commercial photovoltaic power plants consist of photovoltaic modules, brackets, DC combiner boxes, inverters, AC switchboards, etc. Photovoltaic modules convert solar energy into DC electricity, and the inverter converts it into AC electricity for load use.

3. Power Generation Principle: Photovoltaic modules are installed on the roof via brackets, absorbing sunlight to generate DC electricity, which is converted into AC electricity by the inverter, and is preferentially supplied to the building load. Excess electricity can be uploaded to the grid.

II. Development Process

1. Site Selection and Assessment: Select a location with sufficient sunlight, no obstructions, and a stable roof structure, while assessing the local solar resources, policy environment, and electricity price levels.

2. Roof Information Collection and Review: Collect documents such as roof ownership certificates and construction planning permits to ensure that the roof is legally usable, and conduct a safety assessment of the roof structure.

3. Determination of Cooperation Mode and Signing of Agreements: Communicate with the owner about the willingness to cooperate and energy needs, determine the cooperation mode (such as self-generation and self-use, surplus electricity to the grid), and sign a cooperation agreement.

4. Distributed photovoltaics can be divided into four categories according to the investor: individual household, non-individual household, general industrial and commercial, and large-scale industrial and commercial.

5. Filing Principles: Follow the principle of "who invests, who files". The filing is generally valid for two years, and individual household projects can apply directly to the power supply bureau.

6. Distributed photovoltaic projects must have the four functions of "observable, measurable, adjustable, and controllable".

7. Existing projects connected to the grid before April 30, 2024, will still implement the full-scale grid-connected fixed electricity price ("430 policy").

8. From May 31, 2024, new grid-connected incremental projects will fully enter the transitional stage of mechanism electricity prices ("531 policy").

9. New energy project income = mechanism electricity income + market-oriented electricity income + capacity income - various expenses.

10. Mechanism electricity income = electricity energy price × mechanism electricity + mechanism electricity × (mechanism price - market average price).

11. Market-oriented electricity income = market-oriented electricity × market-oriented electricity price.

12. Photovoltaic feasibility studies and corporate information need to be filed with the Development and Reform Commission for approval and financing.

13. The validity period of investment filing is generally two years, and it needs to be extended or re-filed after expiration.

14. Agricultural photovoltaic, fishery photovoltaic, pastoral photovoltaic, and small-scale ground power stations are approved according to the centralized photovoltaic management process.

15. Land pre-examination, site selection opinions, environmental impact reports, safety evaluations, and other approvals from multiple departments must be completed before the project can be launched.

16. After obtaining the "three certificates" of national land use certificate, construction project planning permit, and house ownership certificate, the grid connection can be carried out.

17. Power Access Approval: The validity period of the power grid access approval is generally one year. The access plan must be obtained first, and the formal approval will be obtained after the owner agrees. Overdue applications need to be re-applied.

18. Mainstream component specifications are 210/210R, with an area of approximately 2.7-3.1 m², and mass production efficiency can reach over 24%.

19. The mass production efficiency of TOPCon components can reach over 24%, the theoretical limit is 28.7%; HJT is over 25%; and BC components exceed 27%.

20. During the "dual policies" rush installation period, the component price was 0.69-0.80 yuan/W, with full payment settlement and a delivery cycle of about two weeks.

21. The average annual attenuation rate of monocrystalline silicon components is about 0.5%.

22. Common specifications of inverters are 20kW-350kW, and the price range is 0.11-0.16 yuan/W.

23. Bracket cost: about 0.10 yuan/W for color steel tile paving, and about 0.23 yuan/W for concrete roof (including cement piers).

24. Fund intermediary fee 0.2-0.6/W, common "three three four" or "one three three three" payment methods.

25. 1MW distributed photovoltaic requires about 5000m² of color steel tile roof.

26. Projects exceeding 6MW must be connected to a high-voltage 10kV or 35kV grid; in some areas, projects over 400kW require high-voltage grid connection.

27. Projects larger than 6MW generally require self-generation and self-use, with surplus electricity to the grid participating in the spot market.

28. The total investment cost of photovoltaic is generally between 2.5-3 yuan/W, fluctuating depending on the region and scale.

29. The cost of low-voltage grid-connected cabinets is about 0.05-0.10 yuan/W, and the cost of high-voltage grid-connected cabinets is about 0.40-0.60 yuan/W.

30. Construction and installation costs are about 0.25-0.30 yuan/W. Complex terrain or second-hand equipment may have lower costs, but quality risks should be guarded against.

31. The cost of carport structures is 0.50-0.90 yuan/W, depending on the materials and design structure.

32. Auxiliary materials (bridge frames, maintenance passages, cleaning systems, monitoring, grounding) total about 0.15 yuan/W.

33. Grid connection fees are about 0.10 yuan/W, with an upward trend recently.

34. Project management and supervision costs are about 0.15-0.20 yuan/W.

Roof reinforcement costs approximately 0.10–0.30 yuan/W.

Design and survey costs approximately 0.03 yuan/W.

Operation and maintenance costs approximately 0.035 yuan/W·year, including inspection and cleaning.

First-year distributed power generation ≈ installed capacity × annual effective sunshine hours × 75% system efficiency.

First-year centralized power generation ≈ installed capacity × annual effective sunshine hours × 80% system efficiency.

1 MW ≈ 1000 kW; approximately 1739 575 W components are needed, and approximately 1408 710 W components are needed.

Commercial and industrial rooftop rent is generally 6–8 yuan/m²·month; household rent is slightly higher.

The difference in power generation between flat and inclined layouts is 5%–35%; the angle needs to be optimized based on the site and shading.

Generally, a 20% margin of grid capacity is reserved for installed capacity to avoid overload on the grid side.

For east-west double-sided components, the shading distance ≥ component height × 2.3 times to ensure power generation performance.

Capacity ratio = total installed capacity of components / rated capacity of inverter, typically 1.0–1.5; it can be higher in areas with abundant sunshine.

Photovoltaic insurance rates are approximately one to several thousandths, covering equipment and natural disaster risks.

Annual power plant revenue = annual power generation × electricity price - operation and maintenance costs - insurance costs - labor costs - income tax.

For high-voltage lines exceeding 1.5 km, an additional engineering cost of 300,000–400,000 yuan per kilometer is required.

The general principle of transformer matching is 80% of the component capacity of the rated capacity, combined with safety redundancy design.

Agricultural photovoltaic integration and fishery photovoltaic integration projects can receive additional policy support and subsidies.

Large-scale central state-owned enterprise projects pay more attention to quality and refined management, and the industry has entered the 3.0 stage.

Inventory management and procurement timing of photovoltaic components have a significant impact on project revenue.

Accurate site selection, scientific design, cost control, and a robust revenue model are key to project success.

III. Application Scenarios

1. Commercial and industrial rooftops: Suitable for factories, shopping malls, schools, hospitals, and other commercial and industrial locations; it can reduce electricity costs and improve energy self-sufficiency.

2. Agricultural photovoltaic integration, fishery photovoltaic integration: Combining photovoltaic power generation with agricultural and fishery projects can obtain additional policy support and subsidies.

3. Large industrial parks: Through centralized photovoltaic power plants, meet the electricity needs of enterprises within the park and improve energy utilization efficiency.

IV. Precautions

1. Roof load: Installing a photovoltaic system on a steel structure factory building adds 15 kg per square meter, and 80 kg for brick-concrete structures; the roof load safety must be ensured.

2. Grid connection requirements: Projects exceeding 6 MW must be connected to a high-voltage 10 kV or 35 kV grid; in some areas, more than 400 kW requires high-voltage grid connection.

3. Consumption ratio: Commercial and industrial photovoltaic projects must ensure a high electricity consumption ratio, generally requiring more than 60%.

4. Cooperation model: You can choose a preferential electricity price model or a rooftop rental model; you need to comprehensively consider investment returns and the owner's wishes.

Commercial and industrial photovoltaic development is not only a technical project but also a systematic project involving multiple aspects such as site selection, design, construction, grid connection, and operation and maintenance. Through reasonable planning and scientific management, commercial and industrial photovoltaic projects can bring significant economic and environmental benefits to enterprises and society. With continuous technological advancements and policy support, commercial and industrial photovoltaic development will usher in broader development prospects. It is hoped that the above knowledge points can provide reference for relevant practitioners and help in the implementation of more high-quality projects.