How to calculate the power of an installation

We can install a power of 20,000/8,000 = 2.5 kwc, or a surface of 2.5 x 8 = 20 m2.

Power of a solar panel: calculation, examples and solutions

The power of solar panels determines the production capacity in the installation of the installation. This data is important to make your installation profitable as much as possible. In this article, we will discover what is the power of a photovoltaic panel, maximum, variable and real power, and explain everything with calculations.

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And if you produced your electricity yourself ?

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Power type of photovoltaic panels

On an installation of solar panels, specialists distinguish 3 types power :

1. The maximum power of the panel;
2. Real power;
3. And the power that varies depending on the weather.

That represents the maximum power of a solar panel ? The maximum power of solar panels is based on 1 m². This allows you to have a standard size for all solar panel models combined. We are talking here about the total energy production capacity of the solar panel.

What is the real power provided by a solar panel ?

Since it is rare that all optimal conditions are met, we are talking more about the actual power. The latter takes into account the hazards that are difficult to predict. Indeed, a non -optimal condition contradicts the maximum power provided by manufacturers. It is therefore important to take it into account in its calculations.

Experts noted that the real power of a solar panel represents 75% to 80% of its maximum power (or crest power). At the level of technical sheet, The customer can find this information called Nmot (Nominal Operating Temperature module) or Noct (Nominal Operating Cell Temperature). This power is thus the closest to reality.

Annual production of a solar panel in (kWh) Annual production (kWh) = nominal power of the panel (in kilowatts, kW) x solar capacity factor x hours of annual sunshine.

What is the variable power of a solar panel ?

As seen previously, the power a solar installation East dependent of the weather report, more precisely the level ofsunshine, of the temperatures and season. This means that the production of electricity is not linear, but well variable. It varies over the seasons (summer / winter) and even during the day (in the middle of the day / at night). It is important to have (maximum 1,000 watts per m2), a minimum temperature of 25 ° C, The right inclination of the panels is to 30 ° and not be in a shadow.

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If you are looking to plan power of your solar installation Based on your Annual electricity consumption, you have to take into account of the peaks during the year. Concretely, if your accommodation uses electricity for heating, hot water and cooking, you will have more substantial needs during cold periods. At the same time, your solar installation will produce less electricity than in summer.

How much energy produces a photovoltaic panel of 1 m² ?

To calculate the total production capacity, it is necessary to know the maximum power solar panel for 1 m². Generally, the nominal power of a panel, that is to say when it works in optimal conditions, is expressed in peak watts (WC) and corresponds to the maximum power that a panel can produce, therefore with a light intensity 1000 watts per square meter (W/m²) and a temperature not exceeding 25 ° C on the surface of the panel.

This will depend on several factors such as the efficiency, solar radiation, the angle and the orientation of the panel, etc.

Energy production of a solar panel of 1 m² such as the nominal power of a panel varies from 100 watts to 400 watts peak per square meter (WC/m²), this means that a panel of 1 m² produced, in ideal conditions, between 100 to 400 watts.

Calculation Power Panel Solar

THE calculation is based on the elements below:

• The number of hours of sunshine per year in your geographic area;
• The tilt angle of solar panels;
• Potential temperature losses in your environment.

From this data, apply a decrease on the number of sunshine hours and then multiply by the maximum power of the solar panel for 1 m². The decrease rate is approximately 10% , depending on the shade and temperature variations. If the roof is not oriented south or does not have an inclination of 30 °, The decreasing rate can be higher.

Power power formula = Number of hours of sunshine x Damulation rate x Power power (WC converted to KWC)

What power for the consumption of a home ?

To choose the right power of solar panels, you must first know the electricity needs of your accommodation. For that, nothing could be simpler: see your electricity bill. Expressed in kilowatt hours (kWh), this number indicates the amount of electricity you have consumed on a period (monthly or annual).

On average, 1 kWc product between 900 And 1400 kWh per year ! From this information, it is possible to estimate the electrical power necessary to cover the needs of a home and its occupants. If the home has a self -consumption project, it will be important to in -depth calculate its energy needs. A solar panel with a power of 500 to 1000 WC is suitable for this purpose.

If the installation is capable of producing more electricity than what the accommodation consumes, it is quite possible to resell the surplus of production. In this case, you should consider installing solar panels with a power between 3 and 9 kWc . Individuals can resell all or part of theelectricity produced at EDF OA Solar.

What power to be autonomous in electricity ?

To determine you must determine the consumption electric of your different devices as well as duration use of these.

How to calculate the necessary power ? Energy consumption compared to a time of use is determined in kilowatts-hour (kWh). To calculate the power you will need, you can apply the following formula: total energy consumption (in kilowatts-hour, kWh) / time of use (in hours).

For example, if your Total energy consumption amounts to 13 kWh and you plan to use this energy for 5 hours, the required power will be: 15 kWh / 5 h = 3 kW. Your solar installation must provide a power of 3 kW to guarantee your autonomy !

What elements influence the yield of a solar installation ?

It is not easy to maximize the yield of a solar installation. Indeed, several elements that are difficult to control come into play:

• The level of sunshine in your geographic area;
• Microclima effects;
• The orientation of your house (facing south for more efficiency);
• The inclination of your roof and panels (from 30 to 35 ° compared to the horizontal);
• The type of integration chosen (in buildings or superimposure);
• Any shade zones;
• The outside temperature;
• The nature of the solar connection wiring;
• The distance between the panels and the solar inverter.

To obtain a more specific and personalized calculation as to your future installation, contact our solar expert for free via the number indicated below:

Have your selectra study study your solar panel project !

For more information and know if the project is suitable for your accommodation and situation, have it studied for free by a selectra expert.

Have your solar panel project study by Otovo (ex-in Sun We Trust) !

For more information and know if the project is suitable for your accommodation and situation, have it studied it for free by an Otovo expert.

FAQ on the power of solar panels

FAQ Power of solar panels

�� What is 1 kWc ?

1 kWc corresponds to 1000 WC. This is a unit used for the power of solar panels. A WC (Watt-Rête) represents the power provided under standard sunshine of 1.000 W/m2 with a temperature of 25 ° C.

�� How many solar panels for a 200 m² house ?

On average, a 200 m² house can accommodate 12 solar panels, which represents an area of ​​19 to 20 m². Note that a dozen panels represent a 3 kWc installation.

�� What is the production of a solar panel over a year ?

If the optimal conditions are met (southern orientation and inclination of 30 °), each kWC of photovoltaic panels can produce any 800 to 1,400 kWh per year.

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Our solar guides

1. Solar panel price: the 2023 guide for a solar installation
2. 2023 solar panel assistance: list, approach, eligibility and amount
3. Photovoltaic panels: the solar expertise of Selectra
4. Self -consumption solar panel: opinion, price and aid 2023

How to calculate the power of an installation ?

A solar panel produces electricity intermittently because of the sun’s lighting variations.

The electrical power it provides (expressed in watts) therefore varies according to the hours of the day, but also depending on the seasons.

To be able to compare the power between the panels, we use the Watt Crete (WC), a measure that corresponds to the maximum power that the panel can debit under the optimal STC clarification conditions (Standard test conditions).

These conditions are 1000 W of light/m2 (full sun at noon in temperate zone).

We consider that it takes 8 m2 to produce 1KWC, or 1000 kWh per year.

Why 36 cells ?

The power of a photovoltaic panel in watt crest under radiation of 1,000 W/m2, is intimately linked to its dimensions and its number of cells.

A solar panel is conventionally made up of 36 cells connected in series.

This figure was not chosen at random.

Indeed, to produce a continuous current of 12 V (reference of the voltage used by the batteries, by the economic bulbs), it is necessary to have approximately 14.5 V for an effective load.

Knowing that we are going to lose 2 to 3 V in wiring, so we need a panel providing at least 17.5 V, therefore rounded at 18 V, the voltage of 36 cells in series, knowing that a cell delivers about 0 , 5 and 0.6 V.

A classic 36 cell panel

Calculate power on the basis of electricity consumption

If the objective is to produce the equivalent of its consumption, the power of its installation will be measured by multiplying its annual consumption by the sunshine correction factor in its region (data provided by Météo France).

Take the example of a family with two children who consume 3,600 kWh over the year and who live in the north of France.

The sunshine correction factor is 0.85.

To produce 3,600 kWh with solar panels, this family will need a nominal power of 3,600/0.85 = 4.2 kWc.

This will represent a surface of panels of about 4.2 x 8 = 34 m2. (8 m2 being the estimated surface to produce 1 kWc).

Take another example of a family in Provence which consumes 2,900 kWh over the year.

The sunshine factor in Provence is 1.3. To produce 2,900 kWh it will take a nominal power of 2,900/1.3 = 2.2 kwc, either 2.2 x 8 = 18 m2.

Calculate the power on the basis of the available roof surface

When the well -exposed roof surface is limited, you can calculate the maximum photovoltaic power that can be installed on the accommodation.

Take our Provence family who has 25 m2 of roof exposed south.

The nominal power of a photovoltaic installation covering this roof will be 25/8 = 3 kWc.

Annual production will be around 3 kwc x 1,000 x 1.3 = 3,900 kWh.

Another example, our northern family who has 34 m2 of roof exposed south.

The nominal power of this roof will be 34/8 = 4.2 kWc. Annual production will be around 4.2 x 1,000 x 0.85 = 3,600 kWh.

Calculate power on the basis of the budget

If we have a specific budget, the calculation can be done in the other direction, knowing that the average budget is € 8,000 for 1kwc.

Take a family in Lyon which has a budget of € 20,000.

We can install a power of 20,000/8,000 = 2.5 kwc, or a surface of 2.5 x 8 = 20 m2.

Knowing that in Lyon the correction factor is 1, the annual production of such an installation will be 2.5 x 1,000 x 1 = 2,500 kWh.

In conclusion

Thanks to these formulas, you can quickly get an idea of ​​the dimensions or budget necessary for a photovoltaic installation.

Otherwise, if you have “nomadic” needs then this article which presents the best solar chargers and portable solar batteries will answer your questions.

Check your electrical installation

Before you can fully use your new energy source, it is however recommended to carry out an installation verification.

Whether it is a private house or professional premises, checking your installation is necessary, in particular to ensure compliance with the regulations in force, in France as in Europe.

People’s safety is at stake and, as a family as in a professional activity, no one wants to endanger others in danger. Depending on the specificities of your installation, the standards will not be entirely the same.

This is the reason why it is advisable to involve professionals who know precisely what they must control, with what regularity, and how.

By entrusting this engaging task to a company specializing in electrical energy, you can be more serene, since nothing will be left to chance.

You will have documents that lighten the various checks that have been carried out and you can provide them with all the instances that may ask you, in particular the company charges to insure the premises. You will therefore be in good standing on the whole line.