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Estonian scientist: how do you choose the right solar panels for your home?

The topic of solar panels is getting a wider audience. But if you want to install them in your home, you should first carefully analyze which panels are the most suitable and where it would be reasonable to put them up. Tallinn University of Technology researcher Taavi Raadik, who has worked in the field of solar energy for 17 years, will help answer these questions.

In the form of a solar battery, it is a device that converts solar energy directly into electrical energy. There is no direct wear when converting energy because there are no moving parts. Also, solar batteries do not make noise and do not pollute nature.

“It is purely green production,” says Raadik. He compares the operation of a solar battery to a normal battery: “When a solar cell is exposed to the sun, energy is produced and it is like a normal full battery that gives out energy. But if the cell is not exposed to the sun, it is like a normal battery that has run out.» It is estimated that with the installation of solar panels, it is possible to reduce the annual electricity costs by nearly 60 percent, which then results from the electricity not purchased from the grid and the remaining electricity sold to the grid, so at the current electricity prices, this investment can pay for itself in about seven years.

Different types of solar panels

There are different solar panels and their efficiency also depends on it. “The efficiency of a solar battery is shown by how many percent of the solar energy falling on it the panel can convert into electricity,” says Raadik.

The most common are silicon solar cells, which account for 91 percent of the total market and come in three types. The most efficient and common of them are monocrystalline silicon solar cells, which have an efficiency of around 20 percent. The amount of solar energy falling on one square meter is generally a constant value of 1000 W/m2, so the output power of this type of solar cell is about 200W per square meter installed. They are followed by polycrystalline silicon solar cells, the efficiency of which is about 16-17 percent, so 160-170W for each installed square meter.

“They are cheaper, but therefore also less effective,” he adds. The least common are amorphous silicon solar cells – they can convert only 7 percent of the sun’s energy into electricity.

If the mono- and polycrystalline panels are rigid, then the amorphous one can even be rolled. Therefore, they are mostly used in special solutions where it is necessary for the solar cell to be flexible, for example, integrated into textiles, solutions for hikers, and rounded surfaces.

How to install them?

There are five different ways to install solar panels. Due to our climate, panels are mostly installed on pitched roofs in Estonia. “Ideally, the panels could be at an angle of 41 degrees and located on the south side,” explains Raadik and adds that if the panels are installed to the north, they essentially do not produce electricity, because the sun simply does not shine in that direction.

Alternatively, panels are installed on flat roofs on large industrial buildings and apartment buildings. The advantage of flat roofs is that they can be set to the south and at an ideal angle.

The panels are also installed on the ground – this is how solar parks are built, and this method is also used if there is no possibility to install the panels on the roof. There are also examples where solar panels are installed on house facades and balcony railings.

One of the most effective solutions is the so-called solar tracking system, which allows the panel to catch the sun according to the movement of the sun because the system adjusts the angle to the sun. Such a system is efficient – in the sunniest moments, it can produce 30 percent more electricity than fixed systems.

At the same time, Raadik adds, although it is an effective method, its installation is considerably more complicated and, in summary, much more expensive than other solutions, and it requires more space.

Where to start when installing solar panels on your home?

The first step should definitely be to contact the local government and discuss whether and what the possibilities are for installing the panels. If there are no restrictions in the local government, then a preliminary calculation should be made, how big is the consumption, what are the installation options and how to build the system, and if the numbers are together, an application should be submitted to the network company, with the desire to become an electricity producer.

Then you can order the installation of the panels according to the calculations. But it is also possible to approach the matter very simply: contact a service provider and order a turnkey solution – the electricity company takes over the entire process and administration and guarantees quality. The installation of the panels takes about two to three months in total, and after the work is done, it is immediately possible to become an electrical contractor.

Today, the interest in electricity production from solar energy is very high. “According to Elektrilev, nearly 1,000 people a month apply to start producing electricity using solar energy,” Raadik confirms and adds that if you visit the websites of various service providers, there is also a lot of interest. “Since January, the number of interested people has multiplied. The potential is insane,” he adds.

Due to rising energy prices, many homeowners are trying to reduce energy consumption and are also thinking about making their homes more energy efficient. That is why, for example, SEB bank offers private customers an unsecured loan for the purchase and installation of solar panels, the maximum amount of which is up to 20,000 euros (you can find out about the service HERE). Also, from the beginning of April, the joint institution of EAS and KredEx offers reconstruction support to private houses, which can be used, among other things, for the installation of solar panels – more detailed conditions can be found on the KredEx website.

This is coverage based on the SEB solar panel seminar.

Link to watch/listen to the seminar: Are solar panels reasonable in Estonia? (in Estonian) | Facebook