• Dr. Günter Kast

Small units, big effect.

Moewa 1Start-up. The expansion of large wind turbines has almost come to a standstill in Germany. As a result, a niche is opening up for small, cost-effective and modularly expandable turbines. Two Berlin-based founders want to bring them to series production readiness.

Something is whirring along quietly. It sounds a bit like a distant drone. But in fact it's three small wind turbines on the roof of a five-storey building on Storkower Strasse in Prenzlauer Berg. The electricity generated by the rotors supplies an office in this building, among other things. That is where the brains behind this idea are.

Till Naumann and Andreas Amberger want to make wind energy affordable for everyone with their start-up company Mowea (Modulare Windenergieanlagen GmbH). Their mini-turbines are to be placed where previously only solar cells produced energy. In concert with other clean energies, these wind turbines are intended to make consumers almost independent of the power grid, and even democratize and decentralize the entire electricity market.

At first glance, this looks like a business idea with potential. Couldn't Mowea fill a gap in the market that has opened up due to the problems of large wind turbines? After all, only 280 wind turbines with a total output of 940 megawatts were commissioned in this country in 2019 - the lowest figure since 1998. Above all, administrative hurdles in the approval process - there are fewer and fewer suitable sites available - and lack of public acceptance are standing in the way of the industry. Moreover, the plants are large, complex to manufacture and therefore expensive. Recently, there was even a headwind from the industry's own lobby: some environmentalists said that the scrapping process produces a lot of hazardous waste that is not "green" at all.

Small units, on the other hand, find it easier to find places where they can be placed. They are quieter and cheaper. Alone - the Berliners are not the first start-up to try the idea. Wind turbines that are mounted on the roofs of single-family homes or commercial buildings have been around for many years. In practice, however, many approaches turned out to be useless. The Tassa case, for example, made a big splash. In 2009, the Wolfsburg start-up won a founder's prize from the KfW development bank with its mini wind turbine. However, the system turned out to be immature, with some turbines producing only a fraction of the expected output. Customers demanded their money back and the management had to go to court.

Till Naumann and Andreas Amberger are aware of the gravity of their heritage. "What was offered there in the past was either cheap junk or far too expensive." Also, the private buyer market targeted at that time was far too small. A handful of wind turbines for yachts or holiday homes would not generate enough sales to realize substantial economies of scale. But above all: "There were no modular systems available until now." The two native Berliners now want to change that. "Our micro power plants can be expanded. Dozens of units can be connected in series. This gives us a whole new set of options."

Moewa 2

The starting signal for Mowea was given during Naumann's mechanical engineering studies at the TU Berlin. "When I became a research associate, I was to give the lecture 'Teaching Wind Power'. I had to deepen my knowledge quickly, otherwise I would have embarrassed myself in front of the students. Apparently he succeeded, because later he wrote his doctoral thesis on "Aerodynamics of smallest rotor blades". In 2010, in a research project financed by the Investitionsbank Berlin (IBB) to reduce the costs of wind turbines, fluid mechanic Naumann and Andreas Amberger, at that time a research assistant in the field of electrical drive technology, met.

For the IBB they experimented with modules. The first project consisted of 24 individual turbines and was realized at a wind energy test site of Germanischer Lloyd in the North Sea. Here the modular system of the founders could be measured by an independent party according to the certification standard for wind turbines (IEC 61400).

The mini-turbines looked simple, but were packed with new technology and new materials. They were also small, affordable and efficient. Depending on wind conditions and the number of turbines, they generated electricity in the range between 400 watts and 100 kilowatts.

The results of the test run were encouraging. So encouraging that in September 2017 the two decided to spin off from the TU Berlin and named their baby Mowea. They collected the first 500000 Euros from more than 750 donors via the Berlin crowd investing platform Companisto. People who were convinced of the idea were able to contribute to Mowea in the form of equity financing (partiarisches Darlehen) from an amount of 100 Euros. Further capital came from an EXIST start-up grant.

Initially, the two inventors saw the future market for their wind turbines primarily in emerging markets. There, the mobile phone network is growing disproportionately fast, new mobile phone masts are constantly being placed in the landscape - and supplied with energy by diesel generators. Replacing these generators with small wind turbines attached to the masts - that sounds like a huge opportunity.

"But we had to learn quickly that a small team is not able to do business in distant countries right from the start," Naumann admits in retrospect. "Today I can only advise against such ambitions. Anyone just starting out on their own is overwhelmed by such a task. We simply lacked the experience and manpower. It makes more sense to first see if there isn't a market on our doorstep.

This is obviously available. The turbines could be installed mainly on the flat roofs of industrial halls in commercial areas, but also on the many new mobile phone masts that have to be built to build the 5G network.

When the EXIST funding period ends, the two need follow-up financing. However, venture capitalists are keeping a low profile. "At that time we did not have a pilot customer to show that our micro-turbines actually work. But for investors, this is exactly what is important," Naumann had to learn. Another experience: "The possible applications of our wind turbines are very diverse. They can be placed anywhere where there is even a few square meters of space and sufficient wind. But this is not necessarily an advantage when addressing potential investors. They want to see that the founders have successfully positioned themselves in one of their niches. So it is better not to dance at five parties at the same time, but to choose one and really step on it.

And that's exactly what they're doing. At an alumni event of the "Centre for Entrepreneurship" of the TU Berlin they get into conversation with Vodafone. The telecommunications company is currently planning to build the 5G network and needs many new mobile phone masts for this. Since these are continuously consuming energy, Vodafone is having four Mowea test systems attached to a mast near Torgelow (Vorpommern-Greifswald district) in December 2019. Each of these systems has a peak output of 500 watts and produces between 500 and 800 kilowatt hours per year. Under average wind conditions, this is enough power to supply half of a two-person household - or a good part of the energy required to operate the radio mast.

At last the founders have their pilot project. Because the rotors have a diameter of only 1.5 meters, the requirements for a permit are actually much lower than for large wind turbines.

"Of course we have to comply with the requirements regarding noise emissions and nature conservation regulations (bird strike)," explains Naumann. But since a special anchorage avoids vibrations, the system is comparatively quiet. And thanks to the sophisticated control electronics, any number of micro-turbines can be combined into one system, just like Lego bricks.

"A lot of know-how is needed to make the entire plant work," explains Naumann. "Our turbines on the radio masts are only 35 meters high. There the wind blows less strongly than at 80 or 100 meters, where the rotors of large turbines are moved. So 90 percent of the time the turbines are only working in the partial load range."

In order to be effective nevertheless, particularly precise control electronics are required. In other applications, for example on company flat roofs in commercial or industrial areas, the rotors would even move at a height of only ten meters. "We are therefore not promising a completely self-sufficient power supply. We are talking about an additional system that can reduce electricity costs, preferably in conjunction with photovoltaics.

Vodafone is currently carrying out an amortization calculation based on the pilot's results. In the next step, Mowea is to submit an offer for a further 300 turbines for the future pilot series. "Things are moving forward," says Naumann happily. "We are proud to be part of the sustainability strategy of a global corporation." As long as the turbines prove themselves, nothing stands in the way of series production.

In addition to the technical and economic side, the founders had to go through further learning processes. There were changes in the founding team, tangible differences of opinion. Above all, the fact that only technicians worked together proved to be problematic. "Any double competence is superfluous," says Naumann looking back. "It is important to pay attention to business management know-how and entrepreneurial experience in the team. This should not be someone who is still green behind the ears."

And before signing a memorandum of association - "It's like a marriage contract" - it couldn't hurt to seek advice individually and not just as part of a team. Within the team itself, the individual members should complement each other as well as possible. "This also applies to the different character types. If one of the partners is rather hectic, the other should ideally be a quiet type. A certain balance in the team is already quite good."

The Mowea team currently comprises ten people. In order to obtain additional know-how and financial resources, the entrepreneurs are getting business angels "with smaller tickets" on board and are hoping for deals with institutional investors. The start-up company still needs around one million euros to go into series production - capital that is to be acquired in the next six to eight months.

"There are many inquiries at the moment - despite the Corona crisis. It was a stroke of luck that Vodafone prominently praised our cooperation in a press release and drew the attention of other donors to us. They are now actively approaching us."

However, financing has not yet been secured. Naumann already notices "that some family offices and possible venture capitalists are currently keeping their powder dry". The current crisis is also leaving its mark here. "We simply have to make the pilot run," he reassures himself.

The prototype is currently being manufactured by a partner in Berlin. As a location from southern Germany to eastern Europe or the Far East, anything is possible for series production. The series modules should be on the market in 2021, the target price is 500 euros per unit.

Naumann still believes that the Mowea turbines are best placed on the roofs of commercial properties, where machines run during the day anyway and no one needs to sleep at night. "I wouldn't put a wind turbine on my private house roof myself," he admits. "The noise is already disturbing." The flat roofs of airport companies at airports are also suitable, he says: "The forests around airports have been cleared, there are no wind breaks and no birds that need to be protected. Moreover, photovoltaic systems are taboo there because they could dazzle pilots and air traffic controllers. Our turbines would be a real alternative."

As soon as Mowea gains a foothold in the domestic market, the internationalization plan should also be taken out of the drawer again. "In Africa and India, where the mobile phone network is growing rapidly, there are hundreds of thousands of masts, most of which are still operated with diesel generators," explains Naumann. In order to send signals, these masts themselves need electricity. In this country, this comes from the grid. In developing countries, where there is a lack of power lines, generators often take over this task. "We can reduce the consumption of fossil fuels enormously with our turbines, possibly also in combination with photovoltaic and fuel cells."

With the help of Vodafone & Co.'s distribution network, a concentrated order load could one day come together. "Why shouldn't we perspectively supply 10,000 modules per year to emerging markets that really work and pay for themselves within two to three years? In India alone, there are 500,000 diesel masts - and every year it's ten percent more." ®

Author: Dr. Günter Kast

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