Frequently Asked Questions
Everything You Need to Know About Small Wind Turbines and Energy Storage
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Freen turbines set themselves apart from traditional wind turbines by offering a more flexible, efficient and cost-effective solution to suit a variety of users, from landowners to energy operators. Unlike many turbines designed for large-scale projects, Freen turbines focus on flexibility, making them ideal for confined spaces or areas with turbulent wind conditions. Their unique vertical-axis Darrieus design, based on patented technology and soft blades, maximizes energy conversion efficiency and durability while reducing operational noise, enabling deployment in residential or densely populated areas.
Freen turbines contain fewer friction elements, minimizing wear, energy loss and maintenance costs, and their soft, flexible wings can withstand high winds. Freen turbines boast a 20-year lifespan and low environmental impact, supporting versatile installations both on and off-grid, in hybrid or stand-alone configurations. This combination makes Freen an affordable, highly efficient and sustainable choice in the small wind turbine market. -
Freen turbines are designed for moderate to low wind conditions, classified in IEC wind turbine classes III and IV. This means they are optimised for efficient operation in areas with average wind speeds of up to 7.5 metres per second, making them ideal for inland or lower altitude applications where winds can be constant but not extreme. Their design effectively copes with variable winds, enabling consistent power generation even in regions with variable or weaker wind conditions, such as urban or semi-urban areas. This versatility allows the Freen turbines to adapt to different site-specific wind profiles, while maintaining high energy efficiency.
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Yes, Freen turbines are suitable for residential areas, as they operate quietly and are designed to perform in varied wind conditions typical of such environments. We do not offer roof-mounted models.
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The innovative design of our blades incorporates tensile stress technology using steel cables, which eliminates bending stresses and significantly reduces material fatigue over time. This allows the blades to better handle mechanical stresses, resulting in a longer operational life.
In addition, the blades are highly resistant to sand corrosion, frost, and UV exposure thanks to a protective film and PET sheathing with specialized additives. These features ensure durability and extended lifespan even in harsh environmental conditions.
The flexible design of the blades allows them to adapt to changes in rotor speed and wind gusts, minimizing strain on the turbine’s mechanical components. This flexibility helps optimize performance across a wide range of wind conditions without compromising the turbine's durability. -
The Freen-20 small wind turbines are classified under IEC Wind Turbine Classes III and IV, as per the International Electrotechnical Commission (IEC) standards. These classifications describe the turbines' suitability for specific wind conditions:
IEC Class III: This class is designed for areas with moderate wind speeds, with an average wind speed of up to 7.5 meters per second (m/s). It is ideal for locations with steady, but not extremely high, wind activity. This class is for areas with lower wind speeds, where the average wind speed is up to 6 m/s. It’s perfect for sites with gentle and light wind conditions. Being classed in both IEC III and IV, the Freen-20 wind turbines are optimized to perform efficiently in areas with moderate to low wind speeds, ensuring they can operate effectively even in less windy regions. This makes them highly versatile for various site conditions, including lower-altitude or inland areas where wind speeds may fluctuate -
Freen small wind turbines are certified as follows:
2014/30/EU – Electromagnetic Compatibility (EMC): This certification ensures that the turbines do not generate electromagnetic interference that could affect other electronic devices, and they are also protected against interference from external sources. It guarantees the safe and effective operation of the turbines in environments with other electrical equipment.
2006/42/EC – Machinery Directive: This directive sets safety requirements for machinery, ensuring that the Freen-20 turbines are designed, constructed, and installed in a way that protects users from potential hazards. It ensures a high level of safety and performance throughout the turbine’s operational life.
2014/35/EU – Low Voltage Directive (LVD): This certification ensures that the electrical components of the turbines, operating between 50V and 1000V, are safe for users. It focuses on preventing electrical hazards such as shocks and fires, ensuring that the turbines meet the essential safety requirements for low-voltage equipment.
IEC 61400-2:2013 – Small Wind Turbines: This is an international standard specifically for small wind turbines. It covers the design, testing, and safety of wind turbines with rotor swept areas smaller than 200 square meters. Compliance with this standard ensures that the Freen-20 turbines meet rigorous safety, reliability, and performance criteria suited for small-scale wind energy systems.
Freen has received the registration certificate for our trademark from the European Union Intellectual Property Office (EUIPO). This certification covers classes 9, 37, and 42, encompassing a range of goods and services that underscore our commitment to innovation and quality in the renewable energy sector.
Class 9: This class includes electrical and electronic equipment for windmills, wind power plants, and wind turbines. Our offerings encompass control and monitoring equipment, solar panels, and related accessories designed to enhance the efficiency and performance of wind-operated machines.
Class 37: Under this class, we provide installation, maintenance, and repair services for wind power systems, electrical and generating machinery, and security equipment for wind turbines and wind power plants. Our experienced team ensures that your systems operate reliably and efficiently throughout their lifecycle.
Class 42: This class focuses on technological assistance and consultancy in renewable energy projects. We specialize in the development and testing of wind power systems and conduct scientific research in wind energy to promote innovation and advancement in the field. -
For optimal performance, Freen-20 turbine operates best in wind speeds starting from 5,5 m/s at the height of 20 meters. For maximum energy capture while maintaining high efficiency and low noise emissions the rated wind speed is 12 m/s. When wind speeds exceed the cut-out speed of 17 m/s, the turbine automatically halts to prevent mechanical strain and ensure safety.
Cut-in wind speed for the turbine is 3,5 m/s. In extreme wind conditions, the turbine is built to withstand a survival wind speed of 36 m/s. -
When installing a Freen wind turbine, it’s essential to check with your local authorities to identify any necessary permits or licenses required in your region. You may refer to the local energy company to explore the grid connection regulations. Building permits are usually provided by local municipalities according to their procedures.
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While the installation of the Freen turbines is streamlined, there are important technical requirements to consider, such as foundation specifications, grid or energy storage integration, site access, and local regulatory compliance. Below, as an example, we outline requirements for Freen-20 wind turbine.
Wind turbine foundation: Depending on the geological survey and site assessment, the turbine will require a robust foundation capable of supporting its weight and handling various wind loads. This may involve specific construction techniques.
Power infrastructure: The Freen-20 turbine will need to be connected to the main power board. A certified electrician will be required for this connection to ensure compliance with local electrical codes and safety standards.
For off-grid and hybrid systems, additional engineering, planning and system designing will be required, in order to integrate the turbine effectively.
Site access: The installation site should be accessible for transportation of turbine components. In cases where access is limited, temporary infrastructure such as access roads may need to be constructed to facilitate safe delivery and setup.
Space requirements: Adequate space is needed around the turbine to accommodate both the foundation and the turbine’s operational needs. Although the Freen turbine is designed to optimize land use, there should be enough open area around the turbine to ensure airflow is not obstructed and to maintain safe distances from structures. For instance, the minimum required surface space needed for Freen-20 model is 7 x 7 meters.
Communications: The site should be equipped to support necessary data transmission capabilities. -
Freen turbines utilize our proprietary SCADA (Supervisory Control and Data Acquisition) Desktop service for comprehensive monitoring and performance analysis. The cellular internet connection (SIM card) is required to provide data transmission. Other equipment is supplied by Freen. It is possible to have a demo of the solution per additional request.
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An off-grid installation refers to a power configuration that operates independently of the public electricity grid. These systems generate electricity locally, usually using renewable sources such as wind turbines, solar panels or hybrid configurations, often combined with battery storage to provide continuous power. Off-grid installations are popular in remote areas without access to the conventional power grid, providing energy for homes, cottages, farms or mobile units. They provide energy independence, but typically require careful planning and management to balance energy generation, storage and consumption. Freen-20 turbines are designed for both off-grid and on-grid applications.
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Large, small and micro wind turbines mainly differ in size, power and applications.
Large wind turbines, typically with a capacity of more than 1 MW, are used on wind farms or offshore to supply power to the grid.
Small wind turbines, ranging from around 1 kW to 100 kW, are suitable for individual homes or small businesses, often in rural or solar hybrid configurations.
Micro wind turbines, typically less than 1 kW, power devices with minimal requirements, such as batteries or small electronics, and are often portable, making them suitable for remote or backup applications on boats or in campervans. -
Vertical and horizontal axis wind turbines differ primarily in their design orientation, performance in different wind conditions and maintenance requirements. Vertical axis wind turbines (VAWTs), such as Darrieus (including Freen) and Savonius, have a vertically oriented rotor shaft, which allows them to capture wind from any direction, making them effective in turbulent wind conditions close to the ground, such as urban areas or rooftops. Horizontal axis wind turbines (HAWTs) have a horizontal rotor shaft, usually positioned high on the tower to capture stronger, more constant winds at higher altitudes. This requires a mechanism that rotates with the wind direction.
VAWTs have simpler designs with fewer exposed moving parts, which makes them easier to maintain, while HAWTs design requires more support structures and have higher installation and maintenance costs. -
Vertical axis wind turbines (VAWTs), such as Darrieus and Savonius, differ primarily in the shape of their blades, which affects how they capture and convert wind energy. Darrieus turbines, including models such as the Freen, feature a curved blade design (often resembling an “egg”) that allows them to efficiently capture kinetic energy from multiple directions. Darrieus turbines tend to be more efficient at converting wind energy into electricity and work well in areas with variable or turbulent winds, making them suitable for urban and residential areas.
The Savonius turbine, on the other hand, uses an “S” shaped blade design, which more passively captures wind through drag rather than lift. While they are often less efficient at converting energy, Savonius turbines are simpler, robust and very effective in low wind or lower speeds.
In summary, Darrieus turbines are designed for efficiency in converting wind energy into electricity, while Savonius turbines are valued for their simplicity and suitability for low-speed and low-power applications. -
Home energy storage is becoming a cornerstone of modern living. As energy prices rise and grid reliability declines, homeowners are looking for more control and security. Installing a home battery offers several advantages: backup power during outages, lower electricity bills through peak-time savings, and optimized use of renewable energy. You can also gain independence from fluctuating grid prices and reduce your carbon footprint. Freen’s battery systems are modular, maintenance-free, and certified to EU safety standards, making them a reliable investment for your home and future.
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The most common battery types for home storage are lithium iron phosphate (LiFePO₄), sodium-ion, and zinc-based batteries. Lithium-ion batteries are known for high efficiency and energy density, while sodium-ion systems offer excellent safety and affordability. Zinc-based batteries are emerging as an eco-friendly solution for longer lifespans and recyclability. Freen offers both LiFePO₄ and sodium-ion systems to meet diverse residential needs.
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Lithium-ion batteries deliver high energy density and long cycle life, making them ideal for compact installations. Sodium-ion batteries, a newer innovation, use abundant and non-toxic materials. They are more temperature-resistant, safer in operation, and fully recyclable. While lithium remains dominant, sodium-ion is emerging as a sustainable and cost-effective alternative.
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Freen batteries are manufactured in the European Union, ensuring high quality, safety, and full CE certification. Freen provides local support, fast delivery, and compatibility with both solar and wind systems. Performance-wise, Freen’s LiFePO₄ and sodium-ion batteries deliver comparable efficiency and lifespan to Alpha ESS and Tesla Powerwall, with a more flexible modular design and competitive pricing.
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Yes. Freen systems are designed to grow with your needs. Our modular architecture allows you to add more battery modules at any time, whether you install more solar panels, expand your home, or simply want longer backup capacity.
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Yes. Freen batteries are CE-certified and tested under European standards. Our sodium-ion technologies are inherently stable, and have integrated protection for overcharge, short-circuit, and temperature control.
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Depending on the model, Freen batteries last 6,000–10,000 charge cycles, which equals about 10–15 years of regular daily use.
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Yes. Freen energy storage systems integrate seamlessly with most solar inverters. They can store excess solar energy for later use or serve as a full hybrid system with wind turbines.
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Freen batteries are compatible with most hybrid and off-grid inverters that use standard communication protocols such as CAN. If you already have an inverter and want to confirm whether it works with Freen systems, please contact us
Still Have Questions? Let’s Talk!
We’re here to help with any questions or ideas about small wind turbine generators and energy storage. Whether you need more info, have proposals, or want to discuss your needs, we’d love to hear from you. Let’s power the future together!
