From Theory to Practice: Four Methods for Estimating Photovoltaic Power Generation

Photovoltaic power generation has become an essential part of modern energy solutions, particularly in home solar systems and distributed power applications. Estimating the potential power generation of these systems accurately is crucial for planning and maximizing efficiency.

This article summarizes and compares four commonly used methods for estimating photovoltaic power generation: the national standard formula calculation method, component area radiation calculation method, standard sunshine hours installation capacity calculation method, and empirical coefficient method. We analyze their advantages, disadvantages, and best-use scenarios to help you choose the most suitable method for your needs.

1. National Standard Formula Calculation Method

Overview

To estimate the power generation of a photovoltaic power generation system, it is necessary to know the peak sunshine hours in the area where the system is installed (by comparing the photovoltaic module surface)

The total solar radiation received is converted to an irradiance of 1000W/m

2 hours), system efficiency, system installation Capacity.

For example, a 10kW photovoltaic grid connected system installed in Beijing with a peak sunshine duration of 4 hours

The efficiency is about 80%, so the calculation formula for daily power generation of the system is=component installation capacity x peak sunshine hours x system efficiency

=10 × 4 × 0.8=32kWh, approximately 32 kWh of electricity.

Advantages

• Easy to calculate with readily available data.
• Provides a quick estimate for preliminary assessments.

Disadvantages

• Relies on average sunshine hours, which may vary seasonally.
• Doesn’t account for shading or real-time operational losses.

Best Applications

This method works well for standard system designs or initial feasibility studies for home solar systems.

2. Component Area Radiation Calculation Method

Overview

This method calculates power generation based on the radiation received by each module, using:
\text{Power Generation} = \text{Irradiance (kW/m²)} \times \text{Panel Area (m²)} \times \text{Efficiency (%) }

For example, with 5 kW/m² irradiance, 10 m² of panels, and 15% efficiency, power generation is:
5×10×0.15=7.5 kWh/day5 \times 10 \times 0.15 = 7.5 \, \text{kWh/day}5×10×0.15=7.5kWh/day

Advantages

• Accounts for the specific area and irradiance data of each module.
• Can be more accurate for installations with varying panel angles or layouts.

Disadvantages

• Requires detailed data on irradiance and module specifications.
• Calculations are more complex and time-consuming.

Best Applications

Ideal for precise designs and custom installations where the panel layout or angle significantly impacts performance.

3. Standard Sunshine Hours Installation Capacity Calculation Method

Overview

This method simplifies the estimation process by focusing on the system’s installed capacity and the number of standard sunshine hours.

Advantages

• Straightforward and less data-intensive.
• Effective for comparing systems across different regions.

Disadvantages

• May overlook real-time weather fluctuations and operational inefficiencies.

Best Applications

Useful for large-scale distributed power systems where quick estimations are required.