The facility size you need will depend on several factors, such as your electricity needs, the available solar radiation in your area, and the size and shape of your roof.
Here I will explain how you can calculate the required roof area for your solar system.
Available solar radiation
Solar radiation at a given location directly impacts the potential yield of photovoltaic (PV) systems. In general, higher solar radiation results in higher yields from the plant. This is because PV cells are more efficient at converting sunlight into electricity when they receive more direct radiation.
Therefore, locations with high solar irradiance are usually more suitable for developing PV systems than locations with less solar irradiance. For this reason, PV systems in southern Germany generally have higher yields than comparable systems in northern Germany.
The higher solar radiation in the south enables more electricity to be produced. In addition, Bavarian PV systems, for example, can be smaller than comparable solar systems in the north due to the higher local solar radiation, which means that more electricity can be generated per square meter of the area in Bavaria.
Finally, when determining the yield of a solar powered generator system, it is important to consider local solar radiation conditions to ensure accurate predictions.
- Maximum solar radiation in the north at 1150 kWh/m²
- Maximum solar radiation in the south at 1350 kWh/m²
Calculate the available roof area
The easiest way to find out the dimensions of your roof is to look at your home’s blueprints. This is especially true for houses that are not very old or that you, as the owner, built yourself. However, the building plans are often no longer available, especially for older houses.
If the dimensions of a roof are no longer listed accurately enough in old plans, only your measurement or recalculation will help.
You can easily determine the length and width of your house, as measurements for the floor plan, by measuring or walking from one corner of the house to the other. However, estimating the roof overhang can be more difficult. It is best to measure with a laser measuring device, which you can borrow from most hardware stores.
With the device, you can measure the angle of inclination of the roof from afar. Once you know the angle, you can calculate the roof area by considering the floor plan and the length/width of the house.
To calculate the roof area available for a solar system, you can use roof tiles or roofing stones. To do this, measure the length and width of the roof tile. Then you count or estimate the number of roof tiles or shingles and multiply it by the calculated area.
This gives you a rough estimate of the area available for solar panels. You can also use this method to calculate the space required for rooftop installations, such as air conditioners or satellite dishes.
Determine usable area
The total area of your roof can be larger than the area suitable for a solar system. This is because some areas, such as dormer windows, windows, and chimneys, can be blocked by shadows.
Shading can be caused by trees, power poles, and buildings. If you take all these factors into account when calculating the roof area, you can determine the largest possible area for the installation of your off grid solar system.
Determine the maximum electricity yield
The maximum size of a photovoltaic system for your roof can be determined in two simple steps.
First, determine which modules you want to install. A solar module occupies an area of almost 2 square meters. So if you divide your available roof area by 2, you get the maximum number of modules you could theoretically install on your roof.
- In the next step, you multiply the number of modules by the power of the modules used. Modern photovoltaic modules can achieve an output of 300-400 watts. So if you multiply the number of modules by 400 watts (0.4 kW), you get the maximum achievable system output in kilowatt peak (KW). This simple calculation gives you a rough guide to the maximum size of the photovoltaic system you can install on your roof.
- A PV system’s average annual electricity yield can be calculated by multiplying the system output in KW by the specific solar yield in kWh per KW. In Germany, the average specific solar yield is around 900 kWh/KW, so a 5 kW system would have an expected annual electricity yield of around 4,500 kWh.
- This number varies depending on the plant’s location, as different areas receive different amounts of sunlight. The solar modules’ age and condition also affect the system’s overall efficiency.
Nevertheless, this simple calculation is a good starting point for estimating the maximum electricity yield of your PV system. In addition, you will also find numerous photovoltaic calculators or solar power calculators, which can also help you.
Consider roof pitch
The amount of electricity a solar panel can generate depends on several factors, including the orientation and tilt of the panel. In general, panels aligned with the equator and tilted at an angle of 30 degrees produce more current than those not oriented in this way.
This is because they receive more direct sunlight throughout the day. That’s why you must consider how much electricity you need to produce when choosing the orientation and tilt of your small solar panels. Otherwise, you may get a system that is too small or too big for your needs.
Determine the optimal size of the solar system
When it comes to generating solar power, there are two main factors you need to consider: your power consumption and your desired level of self-sufficiency.
If you want to balance your electricity consumption completely, you must install as many photovoltaic modules as necessary to cover all of your electricity consumption. However, a smaller system may be sufficient if you want to reduce your ecological footprint or save money on your electricity bill.
Consider your power consumption
When choosing a photovoltaic system, you must consider your average electricity consumption. This will help you determine the size of the facility you need.
If you choose a system that is too small, you will not be able to meet all of your electricity needs. On the other hand, if you choose a system that is too large, you will waste money on unnecessary components. That’s why it’s important to find the right balance.
The best way to do this is to look at your past utility bills and average them. With this information, you can choose a photovoltaic system that suits your needs.
PV arrays can power your whole house or just a few devices and can be installed on your roof or the ground. To be as self-sufficient as possible, you can dimension your PV system a little larger and combine it with an electricity storage device.
Excess electricity generated during the day can then be stored and used in the evenings or at night. By consciously increasing the size of your PV system, you increase your production and, thus, your regular surplus electricity.
This additional electricity surplus can then be temporarily stored and used later, for example, for electricity-driven heat pumps or your pool heating.
With a PV system, you are independent of rising electricity prices and grid failures. You produce your clean energy and help protect our environment.
Weigh the costs
A photovoltaic system must be accompanied by an appropriately dimensioned electricity storage device to become self-sufficient. The additional costs for a larger storage system and additional modules that enable 100% self-sufficiency are often out of proportion to the profit.
The additional modules cover occasional consumption peaks but are not required for the permanent power supply. A sensibly dimensioned system with an electricity storage device usually achieves a self-consumption rate of 60-80% but is significantly more economical than a self-sufficient solution. LiFePO4 batteries are widely used in energy storage systems of photovoltaic systems due to their superior power storage properties.
When choosing solar panels, one of the most important considerations is your available space. Monocrystalline modules are the best choice if you only have a limited roof area. These panels are more efficient than polycrystalline panels, allowing you to generate the same amount of electricity with a smaller system.
However, polycrystalline panels might be a better choice if you have more space. These modules are cheaper and can still generate a large amount of electricity. The best option depends on your particular situation and the space available.
Conclusion: Calculate the roof area for a solar system
To install a solar power system in your house, you must first calculate the available roof area. This will help you determine the size of the facility you need. There are a few things to consider when calculating roof area for solar panels.
- You have to decide if you want a system that covers all of your electricity needs or if you want to reduce your environmental footprint.
- Look at your average power consumption and choose a PV system that adapts.
- Third, photovoltaic systems come in different sizes and types – monocrystalline or polycrystalline modules.
- It would be best if you also considered self-sufficiency and whether you want to store the excess energy generated during the day and use it at night.
- Finally, weighing the costs and benefits of installing a larger storage system versus a reasonably sized PV array without storage would be best.
When making these decisions, it’s important to remember that PV systems make you independent of rising electricity prices and grid failures. By producing your clean energy, you are helping to protect our environment for future generations!