Return on investment solar panels

Investing in solar panels can be highly beneficial, particularly in the long term and with the right price. When considering a solar panel installation, one crucial factor is the return on investment (ROI). A higher ROI means faster recoupment of your initial investment. The efficiency of solar panels depends on several key factors, which we will explore in detail in this article.

Calculate the Number of Solar Panels Required

There exists a relationship between the efficiency, area, and peak power (Wp) of solar panels. A solar panel with a given surface area and higher efficiency will generate a greater peak power compared to a solar panel with the same surface area but lower efficiency. In simpler terms, solar panels with higher efficiency require less surface area but generate more output. This makes them particularly appealing when space on a smaller roof is to be utilized. By opting for high-efficiency solar panels, you can still generate the desired power output within a restricted area.

Calculation Examples for Return on Investment

Let's consider an example scenario: You have a roof area of 20m², and you aim to generate 3500 kWh of electricity annually, which is the average amount for a family of three.

Option 1: Solar Panels of 2m² with a Peak Power of 300 Wp

• Solar panel efficiency: 19.2%
• Peak power (Watt): (2m² * 300) / (2 * 1000)
• Required number of solar panels: 3500 kWh / 300 Wp = approximately 12 solar panels
• Area required: 12 solar panels * 2m² = 24m² (exceeds the available roof area)

Option 2: Solar Panels of 1.24m² with a Peak Power of 245 Wp

• Solar panel efficiency: 19.2% * (1.24 / 2)
• Peak power (Watt): 19.2% * (1.24 / 2)
• Required number of solar panels: 3500 kWh / 245 Wp = approximately 14 solar panels
• Area required: 14 solar panels * 1.24m² = 17.36m² (suitable for the available roof area)

Payback Time of Solar Panels

We already mentioned that the yield has a significant influence on the payback time of solar panels. To calculate the payback period, you also need to know the yield of solar panels, which is expressed in Watt Peak power (Wp). However, solar panels do not constantly produce the same amount of power and only deliver maximum power under specific conditions.

In Belgium, solar panels can typically operate at maximum capacity for approximately 850-900 hours per year. The expected output of a solar panel depends on several factors.

Example Return on Investment for Solar Panels

Suppose you want to generate 4,500 kWh per year (for a family of four). You will need 4,500 / 0.85 = 5,300 kWh of solar panel production.

• We: If you have a roof area of 20 to 30 m², you would need 14-21 solar panels to generate enough energy for your household.
• Generated electricity: 4,462.5 kWh (assuming an installation price of €10,800)
• Electricity price: €0.25 / kWh, yields annual savings of €1,115.62

Assuming an installation price of €10,800, based on the above calculations, you can recoup the investment for solar panels within approximately 9-13 years. The payback period ranges from 9 to 13 years, depending on electricity prices, expected maintenance costs, and electricity price developments.

Examples of Return on Investment

Factors Affecting ROI of Solar Panels

There are numerous factors that can affect your Return on Investment for solar panels. Some of the factors are influenceable by your own decisions, however other factors are influenced by nature.

1. Type of Solar Panel