In 2019, Estonian renewable energy company Eesti Elekter produced 18 gigawatt-hours of electricity in the Salme wind farm, which is 10% more than in the previous year. The majority of Salme’s production came from the Eleon 3M116, a 3 megawatt wind turbine based on Eleon technology, with an efficiency of 45.3 percent.

According to Oleg Sõnajalg, Member of the Management Board of Eesti Elekter, two thirds of the output of the Salme wind farm came from the Eleon multimegawatt-class wind turbine last year. “Last year, the Eleon prototype windmill generated 11.915 million kilowatt-hours of electricity, and the efficiency of the wind turbine reached 45.34 percent, which is considered a very good indicator, even for offshore wind farms. As far as we know, no other wind turbine in Estonia has achieved such efficiency,” said Sõnajalg.
Over 45% efficiency onshore wind farms can profitably generate electricity without the support of renewable energy.

According to Sõnajalg, it is good to compare wind turbines based on different technologies in the Salme wind farm, as the company operates not only the Eleon prototype wind turbine but also the Enercon and Vestas wind turbines. “The Eleon prototype produced 3,972 MWh per unit of power, which is 1.95 times better than other Enercon and Vestas wind turbines in the same park, which means the Eleon wind turbine 95% more productive last year – confirming once again that Eleon’s wind technology can successfully can compete with global wind turbine manufacturers.”
There are newer versions of the Enercon and Vesta models than thone in the Salme wind park, but on average, the Eleon wind turbine is 30% more efficient. This is thanks to patented technology that allows to build significantly lighter, taller and larger blades than any other wind turbine manufacturer.

Eleon’s direct drive wind turbine is based on a single-sided supported direct drive (SSDD) invention. The SSDD solves the challenging air gap problem of direct drive wind turbines with a pioneering and unique method. The permanent magnet generator is enclosed in the tubular main frame and fixed by a single main bearing to the front end of the main frame, where the stator is connected to the outer ring and the rotor to the inner ring of the bearing. The generator structure floats, i.e. the complete generator might be deflected but not the air-gap. The hub is also connected directly to the main bearing. With this design the main loads are led from the hub through the main bearing directly to the main frame and, in turn, from the main frame to the tower. The invention protects the generator against harmful off-axial loads that may lead to structural deformations and problems with the air-gap. Mainly torque is transferred to the generator. The invention allows for a significant reduction of the nacelle dimensions and mass.

Eleon wind turbine reliability reached 99.62% last year, which is also above the average for other windmills worldwide. Competitive series wind turbines typically have a required reliability of 95%. For prototypes, 70% reliability is already considered a good result.

After year and a half of negotiations, Eleon has bought a Finnish wind turbine blade factory named Mervento, including all technology and fittings. The Finnish company itself only made it to the production of the first prototype. According to Oleg Sõnajalg, it was the closest factory to Eleon, and therefore a profitable purchase. Oleg and Andres Sõnajalg, founders of Eleon Ltd. are operating in order to launch recently purchased wind turbine blade factory at latest by the end of the year.

“We have had a long-term partnership with Finnish people, unfortunately their factory went bankrupt,” explained Andres Sõnajalg. “Their devices are suitable for our wind turbine blade production. By the autumn, we will move the equipment of the factory to Estonia. “The greatest phenomenon of bringing the wind turbine blade factory to Estonia is that, firstly, it is very labor intensive – it is handmade everywhere in the world,” described Andres Sõnajalg, co-founder of domestic windmill development company.

According to him, in this area there are already qualified people in Estonia. “All the luxury yachts are made from the same materials,” he explained. As a second important aspect, Sõnajalg brought out the transport costs, as bringing wind turbine blades from abroad should be considered with at least a 20-percent additional cost. “Not very large factories are established for the blades, but they are located next to the wind parks, to the point that removable factories will be created,” describes entrepreneur.

A technology company that operated aside the enterprise will help to put up the factory. This should take place in fall, as at the end of September Eleon Ltd. should bring the equipment of Mervento factory from Finland to Estonia.

“These type of factories will be built very quickly,” said Sõnajalg, pointing out that in a few months the factory would be up. The total territory would is estimated to be between two to three hectares. “With this equipment, in two shifts, it is possible to manufacture one blade per week, 52 blades or 17 sets of blades per year,” said Sõnajalg. As planning and calculations are still ongoing, he could not say the exact numbers of the workers yet, however depending on the volume of production, he predicts work places for a few fundred people.

By today, Oleg and Andres Sõnajalg have the signed all the necessary contracts for the construction of Aidu wind farm with total price of 165 millions. 70 percent of Eleon’s wind turbine components come from Estonian companies. These include ABB in Jüri, E-Profiil aside Tallinn, Remeks in Ida-Virumaa as well as many other smaller enterprises.

There are around 200,000 wind turbines in the world. On average, twelve fires involving these turbines take place annually. It is up to each person to decide if this number is too high or not. However, it is a fact that we all consume electricity every day and electricity production with wind turbines is an efficient and environmentally friendly method.

The fire safety of wind turbines suddenly became a topical issue following a recent fire in Viru-Nigula. Since I am in charge of Eleon, a company that manufactures large wind turbines, and we are in the middle of installing a wind farm in Viru County, I consider it necessary to explain why it is completely out of the question that the new wind turbines will catch fire like this. Although an expert analysis will reveal the specific circumstances, which led to the fire in Viru-Nigula, I will try to shed light on the likely causes of the fire.

All big wind turbines appear to be very similar: at the top of a high, bright tower sits a white nacelle, to which three revolving rotor blades are attached. A wind turbine is a wind turbine, people think. That is in fact not the case, as wind turbines that appear to be quite similar employ a wide range of technologies.

Simply put, multi-megawatt wind turbines can be divided into two types: old-school wind turbines with a gearbox and wind turbines of the new generation that are highly efficient and mainly use direct drive. In the case of old-school wind turbines, three factors cause a fire hazard: both the medium voltage transformer and the power electronics, as they are both up in the nacelle, and the housing of the nacelle because it is made from fibreglass plastic, as well as the oil in the gearbox, which acts as a fuel in the event of a fire. The accident in Viru-Nigula likely became possible owing to a concurrence of these three factors.

The wind turbine in Viru-Nigula likely caught fire as a result of the following sequence of events. The medium voltage transformer installed in the nacelle at the top of the turbine, which is constantly shaken by strong winds, created an arc flame, which resulted in ignition. Oil that gushed out of the transformer caused the fire to spread. As the temperature rose, the fibreglass plastic nacelle also caught fire. Oil that poured out from the gearbox literally added more fuel to the fire.

This particular wind turbine (operated by Nelja Energia AS) was produced by Winwind OY, a Finnish manufacturer that went bankrupt in 2013. The technology used in this turbine is from the 1990s and did not meet either the modern safety or efficiency standards.

According to statistics, more than 80% of fire incidents involving wind turbines have originated from medium voltage transformers installed at the top of the tower. The reason is the fact that the nacelle of a wind turbine is constantly shaken by strong winds, which is a phenomenon that everybody who has flown into turbulence on a plane or been at sea during a storm has experienced.
In the course of time, however, constant shaking creates a situation where each detail that can become loose indeed does become loose. And everybody can guess what happens in a nacelle when a seven-ton transformer that operates at a thousand volts gets loose…

This rare but nonetheless dangerous sequence of events could not possibly unfold in wind turbines that belong to the new generation.

The medium voltage transformer in the new generation Eleon wind turbines developed in Estonia is, however, installed in special rooms on the basement floor separated by a firewall. When any devices catch fire in these rooms, the fire does not spread to the nacelle or other systems of the wind turbine. Additionally, the transformer is not exposed to any vibration or shaking on the basement floor. We do not know of any cases where a nacelle fire originated from the foot of a wind turbine.

The fact that the housing of the nacelle of an Eleon type wind turbine is not made from flammable plastic but from fireproof, two-centimetre-thick steel also increases fire safety by a significant degree. This arrangement prevents fire from moving outside of the wind turbine’s nacelle even if the fire does indeed break loose. Fibreglass plastic blades catching fire, which happened in Viru-Nigula, is also ruled out.

Thirdly, the new generation Eleon wind turbine uses direct drive. In other words, it is without a gearbox, which means that hundreds of litres of gearbox oil cannot be found at the top of the turbine, which would have an explosive effect in the event of a fire. These three upgrades alone increase the fire safety of our new generation wind turbines by a significant degree. Fire in a wind turbine is extremely rare and wind turbines are a safe and environmentally friendly choice compared to other possible sources of energy.

In addition to the higher safety standards of the new wind turbines, I would like to highlight another important aspect for the people of Estonia and, above all, the people of the Viru region – jobs. The production of Eleon wind turbines is currently distributed between several countries. We order over 10,000 components from more than ten countries. Our wish is to gradually make Estonia the centre of the production and assembly of the turbine’s components, thereby creating a completely new branch of industry here.

This planned full-scale wind turbine industry means an export turnover of several hundred million euros for Estonia and the creation of new jobs, predominantly in the counties of Lääne-Viru and Ida-Viru. It is vital that the unfortunate ignition of an old-school wind turbine would not tarnish the reputation of the entire industry.

Alas, accidents do happen. However, one does not need to be fearful of similar accidents happening to the new generation of wind turbines. Hundreds of engineers have worked hard on the development of this new generation of wind turbines to prevent such accidents. Wind turbines present a great opportunity for the residents of the Viru region.

Oleg Sõnajalg
Wind Technology Association, board member
AS Eleon, board member