Solar energy is the best and easiest way to self-produce 100% clean energy and save on electricity costs. Sales of solar panels have recently grown exponentially, and the triumph of solar energy is showing no signs of slowing down.

We talked to Reigo Kebja, Head of Solar Energy and Customer Solutions at Enefit Green, on topics related to the development of the field.

The field of solar energy is evolving at a colossal speed. In your opinion, what has given this the biggest boost?

Firstly, I would like to point out the increase in efficiency due to technological developments in solar panels, and secondly, the decreasing cost of technology.

These factors have greatly contributed to the growing popularity of solar energy, which in turn has raised people's awareness on environmental protection and the financial savings they achieve from using solar energy.

When did the popularity of solar energy begin, both in the world in general and in Estonia more specifically?

In the world since 2010 when mass construction of solar farms began. There was an exponential increase in the production of solar energy in Estonia in 2018 when almost ten times more farms were built than previously in Estonia altogether.

The main reason for this growth was the sharp decline in the price of solar panels in 2018 and the end of the national renewable energy support period for solar farms of up to 1 MW.

Speaking of solar energy technologies, which important developments would you point out?

An increase in efficiency, of course, which I think is the most important. The efficiency of the first solar panel, which entered the market in 1954, was about 5%. In 2018, when the boom of solar farms in Estonia began, the efficiency of consumer panels was 17%, today we are already talking about 21%. It means that one solar panel produces by a fifth more energy today than it did three years ago.

This is an important step forward. The increase in the size of the panels has also played a role, due to which the installation costs have been reduced.

What is the lifespan of a solar panel and what affects it the most?

We can say that the panels are currently at a turning point in terms of their lifespan. While in 2018 they mostly mentioned 25 years, then today it is 30 years. The life of a panel is most affected by the durability of its coating materials.

A panel in operation is hot and receives a lot of ultraviolet radiation, so the materials must be very durable. Another important factor is the quality of installation. The panels must not be placed under stress, as tension will cause micro-cracks over time. It is also important to fix the panels properly, otherwise strong winds can create internal tension.

Environmental protection is important also in the field of solar energy, so what happens to panels when their lives are over?

With current technology, about 95% of a panel can be reused. It is estimated that by 2030, 60 million new panels will be produced from recycled solar panels.

Lifespan is a very important factor in terms of profitability. 30 years is a very long time, but the target should be even higher. Why not 40 years, like many baseload power plants, but I believe it might happen in five or more years.

Paldiski solar power plant

The production of solar energy among private persons and household consumers is increasing. Why is it so?

Solar power generation is not only an environmentally friendly and ideological option, but it is also economically viable. This also applies to individuals and household consumers. It is possible to save on network fees by producing electricity with panels installed on a property or house.

In many cases, economic profitability already exists without subsidies for renewable energy. The installation of a solar park in a new office, production or residential building has become a new norm and it is unusual to see new facilities on the roof of or in the vicinity of which no solar park has been built.

Many green movements believe that it is possible to switch to renewable and alternative energy sources at the same time worldwide. Still, it is happening step by step, why?

Every change takes time, as does the introduction of new technology. I would draw a parallel with the appearance of smartphones in the market. The new technology did not conquer the whole world at once, as button phones are still used today. A similar trend will be repeated in the field of solar energy.

Secondly, the distribution network must adapt so that electricity production can take place in a decentralized manner without any reduction in reliability. Also, there is not enough sunlight and wind all year round, but they do complement each other.

I will give an example - Enefit Green's Ruhnu renewable energy solution, where we have built a solar park, a wind farm and batteries, and the biodiesel generators have also been kept.

They complement each other both on a weekly and year-round basis - the one that is most reasonable at a given moment will generate. There is less sunlight in winter but more winds, and vice versa in summertime; spring and autumn have a little bit of both.

However, there are periods when there is not enough wind or sunlight during winter, so there is a need for greater use of storage capacity or fast-start old-fashioned power plants.

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