As the supply of fossil fuels is slowly dwindling and the adverse effects on our planet of producing power in this way are becoming more and more apparent, we need to look at alternative energy production options.
Solar power is an understandable answer as it makes use of a renewable energy resource to provide for our electricity needs. Solar power systems harness the light (and sometimes the heat) of the sun and convert it into energy that we can use in our homes and businesses.
There are several options to consider when deciding which system is best for your needs since all solar panels and systems are not the same. There are different options for solar panels and inverters, amongst other components of a solar energy system. While it would be easy to say this one is better than the others, the specific combination of elements for optimum solar power generation depends on several factors. While a particular combination of components could work best in one instance, it might be the worst for another.
How Does Solar Energy Work?
Solar panel systems, also called photovoltaic solar systems, take energy from the sun and convert it into electricity or power. The amount of power produced is measured in volts or watts and depends on the size of the system and which type of solar cells are used.
Several photovoltaic (PV) cells are combined to create a solar PV panel or photovoltaic panel. Usually, there are 60, 72, or 96 cells in a solar panel, except for thin-film solar panels, which can come in any size you want. Panels are then mounted together in a solar module, and multiple modules are called a solar array.
The cells are made from a semiconducting material – often crystallized silicon. Semiconducting material does not usually conduct electricity, but it can do so under certain circumstances. By using two layers of silicon with specific substances – in most cases, boron and phosphorus – the two slices respectively become negatively and positively charged. They are then able to generate an electric current.
When the sunlight hits the silicon cells, an electron is released. If multiple electrons are released, it creates a direct (or one-way) electrical current.
A solar PV module or PV panel produces direct current (DC) electricity while most homes and businesses use alternating current (AC) electricity. A solar inverter is required to transform the DC electricity to AC electricity. This electricity can then be used in homes and businesses.
If the solar energy system produces more electricity than is required, excess power can be fed into the utility grid or a battery bank. Solar electricity from a battery bank can be used during times when the solar system is not producing electricity like on cloudy days or during the night. A charge controller should be installed between the batteries and the electricity supply to avoid the solar batteries from overcharging and electricity leaking back into the solar system when they are not in use overnight.
The efficiency of a solar panel refers to how effectively a solar PV cell or silicon panel can convert sunlight into energy. Different solar panels and solar installations have different levels of efficiency, and the effectiveness of a single solar cell is usually higher than that of a solar panel. Read more about how solar panels work here.
What Are The Different Types Of Solar Panels?
The main types of solar panels are monocrystalline, polycrystalline, and thin-film panels. Most of the photovoltaic panels in the world today are made of crystalline silicon.
Monocrystalline Solar Panels
Monocrystalline solar panels are made by slicing a thin silicon wafer off a block of a single crystal. A monocrystalline cell has a more uniform look and even color.
They tend to appear darker, nearly black, usually with a black, silver, or white back sheet and are shaped like squares with rounded corners – also known as squircles. Monocrystalline wafers are created by extracting cylindrical ingots from silicon crystal. Four sides are cut from the metal, which is then sliced into thin wafers – creating cells with a squircle-shape. The sides that are shaved off the cylinders are wasted silicon, although some manufacturers use this to produce a polycrystalline solar cell.
A monocrystalline solar cell is made from the highest-grade silicon and has an efficiency rate of between 15%-25%, with an 18% average. Because the solar cells work so efficiently, they have a higher power output and will need less space than cells of the same size that generate less power or are less efficient.
They tend to withstand higher temperatures better but do not function as well when shaded or covered in dirt or snow, but they still perform better than polycrystalline solar panels. Installing micro-inverters instead of a string inverter could maximize the efficiency of a monocrystalline solar panel if this is the case. Micro-inverters are installed at the panel level instead of linking a string of solar panels together, which is the case with a string inverter. By using a micro-inverter system, the solar system will function optimally even if one solar panel isn’t rather than the system output decreasing to the level of a low-functioning solar panel.
These cells are more durable but also produce more waste during the manufacturing process if the excess silicon is not used to the manufacturing of polycrystalline cells. Monocrystalline cells are more expensive but could be a better option if you have limited space.
Polycrystalline Solar Panels
Polycrystalline panels are also referred to as multi-crystalline panels. Fragments of pure silicon crystal are melted and poured into a square mold. Wafers of polycrystalline cells are then cut from this block once it is cooled. Polycrystalline solar panels have an efficiency rate of between 13%-16%. Installations using polycrystalline cells require more space relating to their monocrystalline silicon counterparts to produce the same amount of energy.
The PV cells of a polycrystalline (or multi-crystalline silicon) solar panel are square or rectangular and an uneven dark blue color. The polycrystalline cells have a gem-like look and are usually placed on a silver or white back sheet to create solar tiles.
They are less expensive than monocrystalline cells and can be produced quicker but are less durable when exposed to high temperatures for extended periods.
Although monocrystalline silicon solar panels have slightly higher efficiency, the energy output between them and polycrystalline silicon panels are similar. A polycrystalline solar panel can be up to half the price of a monocrystalline panel, making them more financially viable.
Thin-Film Solar Cells
Thin-film solar cells are made by placing thin layers of photovoltaic material onto a surface or base. Bases for thin-film solar cells are usually made from metal, glass, or plastic. These cells can be made of a few different photovoltaic materials, including amorphous silicon, copper indium gallium selenide, cadmium telluride, gallium arsenide, and organic photovoltaic cells to produce a solar PV panel.
The silicon in amorphous solar panels is not the same as the crystalline silicon that monocrystalline and polycrystalline cells use. Instead, it is non-crystalline silicon that is placed on a base.
Most thin-film cells on the market today work at between 10%-16% efficiency. Amorphous silicon has an efficiency of between 6%-7%, and cadmium telluride’s efficiency ranges between 9%-11%, while copper indium gallium selenide has productivity around 10%-18%. Copper indium gallium selenide is the most expensive thin-film solar cell, while cadmium telluride is the cheapest but has more toxic material cadmium.
Thin-film cells tend to perform better than poly and monocrystalline panels in lower irradiance conditions (or when they do not receive the optimum amount of sunlight) like on a cloudy day or early in the morning.
Amorphous silicon thin-film PV cells could lose their efficiency over the first six months after which it equals out. Their output stays consistent for the rest of the cells’ lifespan. It is essential to consider this and calculate the size of the installation required based on your energy needs while working with the potential output after the initial drop in the efficiency of thin-film solar panels.
Thin-film cells are flexible, making them more versatile in terms of where and how they can be installed. They are better for installations that require less energy output and are a lightweight and portable solar energy option.
Thin-film cells are usually black, brown, grey, or blue and are about 350 times thinner than the crystalline wafers used for poly and monocrystalline solar cells. While the solar cells might be smaller, thin-film panels could be the same thickness as a monocrystalline panel or polycrystalline panel once the frame has been added. These panels tend to be more durable than if the cells were simply adhered directly to a surface like a roof, for example, although that is possible.
They generally use less material, about 1% of the silicon used in polycrystalline silicon or monocrystalline cells. The product’s maneuverability and low weight are combined with lower labor costs, making them more affordable.
Thin-film cells are less sensitive to high temperatures but have a lower lifespan and warranties than other options.
Thin-film solar panels are ideal for large roofs that cannot handle the weight of mono solar panels or polycrystalline solar panels but have the space to accommodate large numbers of thin-film solar panels. They are also used in solar calculators or installed on the roofs of motorhomes, campers, and caravans, where large amounts of power are not required.
Monocrystalline (and to a lesser extent, polycrystalline) solar panels can be produced with a transparent back sheet. The solar panels are mounted in such a way that sunlight can travel through the solar panel, reflect off the ground or another surface and travel back through the solar cells on the back of the solar panel. These Bifacial solar panels maximize the use of solar energy as they can absorb the sunlight in both the front and the back. These panels can produce a higher energy output in the same amount of space.
Mono- or polycrystalline cells can be cut in half by a laser cutter before being mounted in a panel. These half-cut solar cells slightly increase the efficiency and durability of the cells.
Which Type Of Solar Panel Is The Best For My Home?
There isn’t a typical or best solar panel type for your solar system in your home. Rather the installation of the solar system depends on several factors.
Crystalline based solar panels make optimum use of the space at a slightly higher cost than thin-film solar panels. Monocrystalline panels are more efficient and generate more power while taking up less space. They are also more expensive than polycrystalline silicon panels. If the size of the solar panels is the primary concern, it is best to opt for a solar panel that produces the most output for the space it takes up. For example, a monocrystalline silicon panel rated at 220-watt will require less space than a polycrystalline panel with the same production output.
If cost is your main concern, but you have adequate space, thin-film solar panels could be the best option.
Cost And Efficiency Ratings
Installing polycrystalline panels could save you money upfront, provided that you have space. Monocrystalline panels, on the other hand, require a more substantial investment in the beginning but have the potential of more significant savings on power bills later on due to these panels’ efficiency in producing power.
The efficiency of solar cells or the output is measured under Standard Test Conditions (STC). These testing conditions regulate how much power a solar cell can produce if the solar cell receives 1. 000W/m² of sunlight while being kept at 25°C with an air mass of 1.5.
As we mentioned, thin-film panels are less affected by higher temperatures, which means that they could produce more energy in hot climates than crystalline solar panels.
Most monocrystalline and polycrystalline solar panels come with a 25-year warranty, although some could work effectively for much longer than that.
As the demand for solar energy products rises, so does the research and development in solar technology. For example, a biohybrid solar cell uses organic matter in combination with inorganic matter to recreate the photosynthesis process. Biohybrid cells have a high conversion efficiency of solar energy – nearly 100% in theory since no power is lost by converting chemical energy to electrical energy and is cheaper to produce than PV cells, but their lifespan is considerably lower. Currently, biohybrid cells can only function for a few weeks up to nine months.
When looking at the best options for a solar system, it is essential to consider the efficiency of a particular cell type and the amount of space available for the solar system installation. Temperatures and the location of your solar panel installation are also essential factors to consider. While some solar systems might seem to be less expensive due to the initial investment, it might not be the best solar energy system for your needs.