In the planning of photovoltaic (PV) power stations, the primary consideration is whether the economic benefits meet expectations.

Generally, a shorter investment payback period implies a higher photovoltaic power output. So, it is essential to estimate the electricity generation of the photovoltaic power station before installation.

Different materials for photovoltaic modules have varying photoelectric conversion efficiencies:

Project

Monocrystalline Silicon Module

Polycrystalline Silicon Module

Amorphous Silicon Thin Film Module

Concentrated Photovoltaic Module

Manufacturing Level

Mature process, diverse models, supports large-scale production

Mature process, diverse models, supports large-scale production

Mature process, diverse models, supports large-scale production

Not commercialized, not yet capable of large-scale production

Technology Maturity

Mature

Mature

Mature

Immature

Photoelectric Conversion Rate

18%~20%

16%~18%

5%~9%

25%~30%

Applicable Locations

Suitable for areas with high direct radiation; performance decreases at high temperatures

Suitable for areas with high direct radiation

Suitable for areas with high diffuse radiation, less affected by temperature, requires 40% more area than the first two types

Requires a sun-tracking system and a large installation area

2. Inverter Conversion Efficiency

The conversion efficiency of inverters is influenced by many factors. For estimation, it is sufficient to select the efficiency provided in the product manual. Currently, photovoltaic inverters have a conversion efficiency ranging from 90% to 97%. Specific data should be checked in the datasheet of the target inverter.

the-inverter-conversion-efficiency

3.Calculating Annual power generation for the PV solar station

3.1 Total Solar Radiation on a Horizontal Surface

Horizontal solar radiation refers to the total energy from solar radiation on a horizontal surface at a specific geographic location. This includes both direct radiation from the sun and diffuse radiation scattered in the atmosphere. It varies throughout the day due to changes in the sun’s position, cloud cover, and atmospheric thickness, and differs by season and location.

When predicting the output of a home photovoltaic power station, it is important to find the annual solar radiation in the home area.

Below are the annual average solar radiation values for different regions in Germany:

Germany_GHI

You can choose the required annual solar radiation value based on your address. In order to be used for the following photovoltaic power generation forecast calculation.

3.2 Orientation of Photovoltaic modules

The orientation of photovoltaic panels significantly affects the power generation efficiency of a photovoltaic power station. Orientation refers to the direction the panels face to receive the most sunlight. In the Northern Hemisphere, photovoltaic panels should face south to capture the maximum possible solar radiation throughout the year since the sun primarily shines from the south.

Panels can also be oriented east-west, known as all-day orientation, to better utilize morning and evening sunlight. Although midday power generation may be lower, the total daily output could be higher.

Orientation Reference for Germany in the Northern Hemisphere:

3.20sunrise-and-sunset-time
12.22-sunrise-and-sunset-time

From the above two pictures, you can clearly see where the sun rises and sets in March and December. The best photovoltaic panel orientation in Germany is where the two pictures overlap.

3.3 Tilt Angle of Photovoltaic Mounting Systems

The tilt angle of photovoltaic panels is the angle between the panels and the horizontal ground. This angle is crucial for maximizing solar radiation reception and energy output of the entire photovoltaic system. Ideally, the tilt angle should equal the latitude of the installation location to receive the maximum direct solar radiation.

The tilt angle of photovoltaic panels refers to the angle between the panels and the horizontal ground. This angle significantly affects the reception of sunlight and the overall energy output of the photovoltaic system.

For residential photovoltaic systems, the installation position is fixed. To achieve higher electricity generation, it is advisable to adjust the tilt angle of the panels to the optimal angle as much as possible. This allows for maximum solar radiation absorption and consequently higher electricity production.

Optimal Tilt Angle Calculation:

The optimal tilt angle ensures maximum solar radiation reception. However, the sun’s position changes daily and seasonally. Typically, the optimal tilt angle is estimated using the latitude and longitude of the area.

the approximate ideal inclination for solar panel installation can be calculated using equation (1):

the angle calculate method

Where:

M——annual angular average, in degrees;

ϕ——latitude, in degrees;

L——longitude, in degrees

Calculation of the Equivalent Solar Radiation for the Tilt Angle of Photovoltaic Panels:

Equivalent solar radiation value refers to the radiation value of the sun light on the photovoltaic panel, which can be calculated by a series of formula conversion and local level solar radiation value.

Formula for the equivalent solar radiation value:

the sun calculate method

α is the angle of Solar Azimuth, Solar azimuth is an angle that describes the direction of the sun in the sky relative to the observer, which changes over the course of the day and throughout the year.

PAZ——Component installation capacity(kWp)

Ep——PV station power generation(kWh)

Es——Irradiance under standard conditions (constant =1kWh / m2)

For example, in Berlin, longitude and latitude is 52.5244°, longitude is 13.4105°, the installation of a 1600W PV solar power station, its power generation is expected to be:

belin pv calculate

Electricity generation calculation considers the equivalent solar radiation based on tilt angle and orientation. Estimating electricity generation involves incorporating the above values, but different orientations will still yield varying results.

4.Simple Formula for Estimating Power Generation

To estimate the power generation of a photovoltaic power station simply, you can use the annual solar utilization peak hours to calculate the station's power output.

Annual peak solar utilization hours is a measure of the average number of hours of solar energy available in a region during a year. That is, the peak solar time. It is often used to assess an important indicator of the power generation potential of solar photovoltaic systems. In simple terms, the annual peak solar utilization hours represent the total amount of solar energy available in a region in a year if the solar intensity is constant at the ideal state (that is, a power of 1 gigawatt per square meter).

Power generation calculated by peak solar time:

h——the region’s average annual peak sunshine hours, found in tables listing the average annual sunshine hours for various regions.

PAZ——Component installation capacity(kWp)

Ep——PV station power generation(kWh)

Central-Germany

5. Simulation Calculation Websites

Users can fill in photovoltaic information and installation location details on simulation calculation websites to get detailed investment return simulations. One such website is https://solar.htw-berlin.de/ where you can input your specific situation.

By using these guidelines and tools, you can estimate the power generation of a photovoltaic power station and assess its economic feasibility.

You can also look at the revenue calculation of the power station, comparing the proportion of the power generation to the home load in the same comparison way.

About the new equipment of the balcony PV power station, it perfectly complies with the new regulations of 800W.

Contact us