One of the basic questions every consumer asks when researching solar energy is how does a PV installation work and how many solar panels we need in our self-consumption photovoltaic installation to make the most of it and make it economically profitable. Five, ten, fifteen?
The reality is that there is no specific number, because the data will depend on a number of factors such as: the space we have on the deck or roof of the house; the size of the solar panels; what is our monthly energy consumption; where our house is located and its orientation; or the power contracted for the electricity supply and the power of the solar panels themselves.
However, even if we make an approximate estimate, it will always be necessary for a professional to advise us and analyze in detail all our needs and the characteristics of the property. Because the decision will be a sum of these factors, which will determine the number of solar panels needed in a photovoltaic installation for self-consumption in homes.
Next, we\’ll take a more in-depth look at the main aspects which must be taken into account to achieve, in the most approximate way, calculation of the solar panels we will need at our unit.
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Factors to know how many solar panels a photovoltaic installation needs
Before calculating how many solar panels are needed for a particular house, it is necessary to consider some elementary previous factorssuch as those mentioned in the second paragraph.
Energy consumption of the house
This is a key factor to consider before sizing your solar installation. To calculate it, you need to see how many kilowatt hour (kWh) we consume for a year.
The data represents the total kWh of all electrical appliances and appliances in operation at all times of the day. Then we will explain with an example How is the energy consumption of a house calculated?.
Contracted power for electricity supply
Another very important factor that influences how many solar panels a solar photovoltaic installation needs is contracted power for the supply of electricity, which is measured in kilowatts (kW). Depending on this data, it will be necessary to have more or less solar panels.
At this moment it is necessary to mention that the most suitable thing is to install solar panels, at least, with the same power as the one contracted with the marketing company. This is the way to guarantee that the installation for solar self-consumption meets the consumption needs of the home.
The types of solar panels that are installed
Another element that needs to be evaluated is what types of solar panels They are going to be installed because they are different, each of them having different powers and features as well as their size. And because the power is different, depending on what it is, a greater or lesser number of solar panels will be needed to cover the demand for consumption and contracted power from a home.
As I explained in another Powen article, there are three types of solar panels: SOLAR (subdivided into monocrystalline or polycrystalline), which transform sunlight into electricity; THE thermal, which generates heat from sunlight; and hybridswhich produce electricity and heat simultaneously.
Available roof area
Once we know how many solar panels we will need, we will check if we have enough space to install them. It is necessary to have enough space to place the number of solar panels we need, considering that each solar panel has an area of about two square meters. In addition, if there is a shaded area on the roof, this will also limit the power to be installed.
House orientation and roof pitch
In Spain it is recommended South orientation (South-East or South-West), being the one that receives the most solar radiation during the day because we are in the northern hemisphere.
The the tilt of the solar panels is also a key factor to consider. Although the angle of incidence of the sun varies throughout the year, since we cannot vary the inclination of the plates according to it, it is highly recommended to see what it is. the most optimal global tilt, which is usually around 30º.
Possible obstacles on the roofs of houses
In the end, when calculating the available surface we will also have to reduce obstacles we can findbesides the fact that it takes into account the number of solar panels that the photovoltaic installation needs, in order to know if it is going to work at its maximum or not.
Obstacles can be physicists, such as a chimney, vent, window, etc., or also in the form of shadows which can limit the power of the solar panel.
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Calculate your energy consumption before installing solar panels
Having listed the factors that we must take into account before installing solar panels in homes, we must also point out that the number of panels will depend on how much electricity we will need. As previously stated, the electricity consumption of a home is a very important factor.
That\’s what it\’s for know the kWh we consume and the hours of the day in which we consume these. This data will be essential to analyze the number of solar panels we will need and what type of installation will be most appropriate, in addition to whether batteries will be needed for the solar panels to store the surplus generated for later use and not directly. when the electrical energy generated in the installation is thrown into the network.
Because it is not the same thing to consume the most during the main hours of the day and do it using the direct electricity generated by the photovoltaic panels, that it is to consume especially when there is no sunlight, in which case having a storage of energy. system like solar batteries is more than interesting.
If we already have an electrical installation in operation connected to the grid, we can quickly and easily check the energy we consume (kWh) on the electricity bill.
Example: consumption of 10,000 kWh/year in Madrid
Let\’s see below through a clear examplehow much energy our solar installation will have to provide us based on our annual consumption.
Let\’s say, for example, that we have an annual consumption in sunshine hours of 10,000 kWh/year and that the geographical area in which we are located is Madrid, whose peak hours are 1,600 on average per year. Peak Sun Hours are the result of the sum of the annual hours in which the solar panels receive 1000W/m2, i.e. they operate at maximum theoretical power.
The approximate calculation of the solar panels we would need in our installation would be as follows:
- Consumption of the house in hours of sunshine: 10,000 kWh/year.
- Peak sun hours in Madrid: 1,600 HSP. Total required power of the solar panels: Home consumption / HSP = 10,000 / 1600 = 6.25 kWh = 6,250 Watt.
In other words, a total power of 6,250 watts of solar panels will be needed. If the solar panels are, for example, 320 W each, the final calculation would be:
Total power of solar panels / Unit power of the panel = 19.53 solar panels -> 19 or 20 solar panels would be what we would need in our installation for our annual energy consumption.
Trust the Solar Photovoltaic Experts
Although it is true that with these tips you can get an idea of the specific needs of your home, it is always good to trust experts in photovoltaic solar energy for the realization of an installation.
So, put yourself in the hands of professionals who make a report and a complete analysis of the characteristics and power and consumption needs of your home. They will know better than anyone how many solar panels a photovoltaic installation needs for a home like yours and will choose the right number and type of panels for your specific case.
