The profitability of wind turbines could rise dramatically thanks to an invention made by a Romanian researcher. Gheorghe Cristea is 55 years old, and he's been working at the Research Institute for Electrical Engineering (ICPE) ever since 1981, when he graduated. He invented various systems that brought him recognition around the world. The new invention is about to be approved and has high chances to revolutionize the technology of wind turbines. Green Report interviewed the Romanian researcher who explained his work in detail.

What does this new invention do?
I invented a new type of rotor for windmills, it's named REVIR and works for mild winds. It's intended to be used as a subset for wind turbines. Its blades are made of thin plates, which may be of various types of materials, carbon fiber or steel spring. They are flexible and can create a large surface lift. All six blades have a large surface where the wind blows. This area creates rotation and its shaft couple is two and a half times higher than the one at the classic models. This basically means that it spins much faster than a normal wind turbine. Hence, it can be placed in many different areas.

What are its advantages over a classic one?
The classic three bladed wind turbines are straight. They have one big disadvantage. When they train a generator to produce electricity, the wind must blow at least 2.5 or 3 meters/second to be able to overcome the shaft couple. Otherwise the blades don't work. Once they start to spin, it will still take time and wind power to reach 4 or 5 meters per second, for the turbine to produce electricity. REVIR rotor does not have this disadvantage, the blades begin to spin when the wind blows by 0.5 meters per second. Thus, in the same operating mode, it produces energy more quickly. The rotor I invented begins to produce power when the wind blows with 2, 3 meters per second, at the same time a classic one begins to spin.

Another big advantage is that REVIR doesn't make that noise which is specific to wind turbines. The classic ones has radially arranged blades under a certain inclination for the shaft couple. Blades beat the air and create the specific roar sound that is underlined in the European standards, so turbines can't be set in residential locations. We tested our turbine at very high speeds and it does not make this noise. When they spin, the blades cut the wind. It's like you would splash your hand in the water and you hear a noise, but if you do it with the lateral part of your hand, you no longer hear anything. The same principle is applicable here. Also, this type of rotor does not require any wind cutout when it blows too hard. The blades are elastic, they move backwards and decrease the propelling power. So the turbine stays stable and does not overcharge, regardless of how hard the wind blows.

What applications does this type of rotor have?
The rotor can be set on different power generators, both on battery pushed turbines, as well as on those without batteries. We want to enter the market with the LED wind turbine that has batteries and bulbs lighting up only when the wind blows. It can be placed in the garden or on the seashore, where there is a breeze all the time, and can light during the night. Wind has a shaft that is spun by the wind, the axis starts the micro-generator, which ignites the bulbs. LED wind is a specific application developed to eliminate the interface between the power generator and storage.

How did this idea for this type of rotor occur to you?
Italians are extremely interested in this technology. I had contact with them, but we didn't reach to an agreement. For the last several years, they've been investigating a technology that has a beautiful design and a small size and can be installed on the seashore to make light without any batteries. I don't know if they finalized anything, as they haven't released anything on the market yet. From my point of view, this problem is solved. I even checked the technology on bikes. I installed the rotor and the wind produced during a bike ride lights the bulbs.

How much would a micro LED wind turbine cost?
I hope to manage and set the price somewhere between 100 and 200 euros. We work with a company, we come with the rotor and the company brings in the rest of the system. It will sell through our collaborator, which will allow the system to enter the market at a lower price.

What is the next step?
Until the winter holidays, I want to finalize six wind turbines in various sizes. For the time being, we focus on developing the prototypes, because the documentation is not ready yet. One of the turbines will have a one kilowatt generator that can charge 48 volts to output, which means it can load a group of four batteries. It implies quite a saving for a home. It basically supplies your fridge, TV, lamps and other home appliances, covering about 30% -40% of a house's consumption needs. Plus, it's very quiet.

How has your invention been seen so far?
I was surprised, a lot of people are expecting us to launch the wind turbine on the market. It's a shame to give technology abroad and then buy it back at double or even triple prices. I noticed that in all the fairs we participated so far.