The growing awareness of environmental issues and the need for sustainable energy sources has led to a significant increase in the adoption of photovoltaic panels around the world.
Photovoltaic panels are a type of solar panels whose function is to generate electricity from sunlight. These types of panels are an essential component in all photovoltaic installations.
How do photovoltaic panels work?
Photovoltaic panels take advantage of the photovoltaic effect, which is based on the ability of certain materials to generate electricity when exposed to sunlight.
At the atomic level, this process occurs due to the movement of electrons in the material when they are struck by photons of sunlight.
Below is a detailed description of how photovoltaic panels work:
Photovoltaic materials
Photovoltaic materials used in solar panels are generally of two types: crystalline silicon and amorphous silicon. Crystalline silicon is the most common and efficient, while amorphous silicon is more flexible and used in specific applications, such as thin panels.
Electricity generation
When sunlight hits the surface of a photovoltaic panel, the energy of the light photons excites the surface electrons in the silicon atoms causing them to jump to another atom.
This property creates a flow of electrons or electrical current, which is captured and channeled through wires connected to the panel .
The electrical current generated by solar panels is in the form of direct current (DC). To be used in most electrical applications, this current must be converted to alternating current (AC) using a device called a solar inverter.
Another option is to store the generated electricity in batteries for use at night or on cloudy days. In this case, it is not necessary to convert the current, but I do recommend installing a charge regulator.
Uses and applications of photovoltaic panels
Photovoltaic modules are used to generate electricity. However, the characteristics of these panels make them an ideal choice for a wide range of applications in various industries and environments.
Below I provide you with some of the most common applications:
Generation of electrical energy for the electrical network
Many electricity companies buy excess electricity generated by small and medium-sized producers to help supply the rest of the population.
Power for remote homes
In rural or remote areas where access to the traditional electrical grid is not possible, solar panels are a viable solution for generating electricity.
This allows people to live more comfortably and sustainably without the need to build long power lines.
Vehicle electrification
Solar cars are a type of electric vehicle that uses solar panels to charge their batteries while parked. This solution allows increasing the efficiency and autonomy of the vehicle by reducing dependence on the electrical grid.
Despite the fact that this option is still in an embryonic phase of development, many companies are investing to be able to produce this type of vehicle at a reasonable cost.
Pumping water
In agricultural regions and areas where water is needed for irrigation or consumption, solar panels are used to power water pumps, reducing the need for combustion engines and the reliance on conventional energy sources.
space applications
Solar panels are also used on spacecraft and satellites to convert sunlight into electrical energy in the vacuum of space. The efficiency of photovoltaic panels is much higher in space since the part of the radiation absorbed by the Earth's atmosphere is not lost.
Advantages of photovoltaic panels
The adoption of solar panels has accelerated due to a number of key advantages:
Renewable and sustainable energy
Solar energy is inexhaustible and environmentally friendly, since it does not emit greenhouse gases or other pollutants during its operation.
Long-term cost reduction
Despite the initial investment, solar panels significantly reduce electricity costs over time since sunlight is free and abundant.
Energy independence
Generating electricity from solar panels gives users greater independence from fluctuations in fossil fuel prices and the electrical grid.
Low maintenance costs
Photovoltaic panels require minimal maintenance and have a lifespan of decades, making them a long-term investment.
Disadvantages
Despite the numerous advantages, widespread adoption of solar panels also faces challenges:
Initial cost
Installing a photovoltaic system can be expensive, although costs have decreased significantly in recent years due to technological advances and government subsidies.
Climatic variability
The amount of power generated by solar panels depends on weather conditions and geographic location. Cloudy or rainy days can reduce generation efficiency.
Energy storage
The lack of an effective storage solution can make solar energy less reliable at night or on cloudy days.
Environmental impact of manufacturing
The production of solar panels involves the extraction and processing of materials, which has an initial environmental impact. However, this impact is usually less than that of producing energy from fossil fuels.
Electrical production from photovoltaic panels
The values in the table below are based on standard test conditions (STC) and for each type of solar panel (1.9m2) in a region with an average of 6 hours of sunshine per day:
|
Type of solar panel |
Estimated production (Wp) per panel |
Average daily production (Wh) |
|
monocrystalline silicon |
300-400 Wp |
1800-2400 Wh |
|
Polycrystalline silicon |
250-350 Wp |
1500-2100 Wh |
|
Amorphous silicon (thin-film) |
150-250 Wp |
900-1500 Wh |
|
bifacial panels |
350-450 Wp (may vary more) |
2100-2700 Wh (may vary more) |
|
Thin layer panels (CIGS) |
200-300 Wp |
1200-1800 Wh |
Example calculation: How many solar panels do I need for a 150m 2 house ?
The number of photovoltaic panels you need to supply a 1,500-square-foot home with electricity depends on several factors, including average electricity consumption, geographic location, the type of panels chosen, and the orientation and tilt of the panels.
However, to get a rough estimate, it can be considered that in areas with good solar radiation, a typical 300-400 watt-peak (Wp) solar panel can produce around 1.5-2.0 kilowatt-hours (kWh) of electricity per day under ideal conditions (approximately 6 hours of effective sun per day).
If your house consumes, for example, 20 kWh per day, you would need around 10 to 13 solar panels of 300 Wp each to cover that daily demand under ideal conditions.
Standard Test Conditions (STC) of a solar panel
"Standard Test Conditions" (STC) are used to standardize the measurement of the performance characteristics of solar panels and allow accurate comparisons between different manufacturers and models. Standard test conditions are as follows:
- Solar irradiance: Solar irradiance is 1000 watts per square meter (W/m²).
- Cell Temperature: The solar cell temperature is maintained at 25 degrees Celsius (77 degrees Fahrenheit) during testing.
- Sunlight spectrum: The sunlight used for testing conforms to the AM1.5 spectrum, which represents the energy distribution of sunlight in the Earth's atmosphere at noon.
- Angle of incidence: The angle of incidence of sunlight is adjusted so that it is perpendicular to the solar panel.
- Wind speed: Wind speed is kept at zero.