Analysis and Discussion of Off-Grid Small Wind Power Systems

Wind power generation has a rich history and is crucial for exploring clean energy. The depletion of fossil fuels and environmental damage necessitate the urgent adoption of clean energy sources.

Wind power generation is the most environmentally friendly, technologically mature, and cost-effective clean energy option. Large-scale grid-connected wind turbines have experienced rapid annual growth of over 20%.

Large-scale wind turbines require significant wind resources. On the other hand, small and micro wind turbines with individual capacities below 100 kW have experienced rapid development due to their wide range of applications, low investment requirements, and low demands on wind resources. Common applications of small wind turbines include household use in remote areas, as well as urban road and landscape lighting.

Technical Features and Challenges of Small Wind Power Systems

Small wind power systems are off-grid clean energy solutions with various applications, such as remote area households, urban road lighting, and landscape illumination. In recent years, small wind power systems have experienced rapid development due to advancements in electronic and energy storage technologies. However, there are still technical features and challenges that need to be addressed for their healthy development.

Differences from large grid-connected wind power systems

The objective of small wind power systems is to provide clean energy for local use, addressing the electricity needs of areas where the grid is not accessible. Therefore, equipment selection is based on the location of use rather than the working environment.

Low wind speed power generation

In densely populated areas, the power available from wind energy is relatively low. To effectively utilize small wind power systems in these areas, the challenge lies in addressing power generation at low wind speeds.

Need for redefining parameter standards

Small wind turbines commonly adopt parameter definitions from large turbines, like a rated wind speed of 12 m/s. This overlooks power generation at low wind speeds, leading to under-designed system capacities due to users’ limited understanding of generation characteristics at different wind speeds.

High safety requirements

Small wind turbines are commonly used in locations close to people and often in large quantities. Therefore, there are stringent safety requirements for the turbines.

Price limitations: Due to price limitations, small wind turbines cannot employ expensive materials and complex control methods to address safety and reliability issues.

Lack of professional installation and maintenance personnel

Small wind power systems often lack dedicated professionals for installation, maintenance, and repairs.

Balancing low wind speed generation and reliable protection during high winds: Small wind turbines need to achieve effective power generation at low wind speeds while ensuring their own safety during high winds. This is a challenging task that requires a unified approach.

Long lifespan and safe decommissioning

With the absence of established retirement mechanisms, small wind turbines should have a long lifespan and be able to safely decommission at the end of their life without posing environmental or safety hazards.

Overall, addressing these technical features and challenges is crucial for the successful and widespread adoption of small wind power systems, enabling them to contribute significantly to clean energy generation.

Current Status of Small Wind Power Systems in China

Small wind power systems in China face challenges due to the lack of specific standards and misleading practices by manufacturers. This can result in system failures and loss of consumer confidence due to cost-cutting measures and misrepresented power parameters.

Small wind power systems are used in off-grid environments, integrated with electrical devices. Matching wind resource with electrical load is crucial. They are suitable for fishing boats, fish farms, remote areas, and rural heating in northern regions. Wind power heating is ideal due to ample wind and short daylight hours. Thermal storage reduces costs and maintenance compared to electrical storage.

Concerns Regarding Wind-Solar Hybrid Street Lights

Wind-solar hybrid street lights, which were once popular in China, appear to be primarily a concept driven by the government’s energy-saving and emission-reduction initiatives.  However, from my perspective, it seems to be more of a hype rather than a practical solution.  Can you find a whole street with wind-solar hybrid lights still operating normally three years later?  I believe there are several main issues with wind-solar hybrid street lights:

Safety concerns:

The blades of small wind turbines are typically made of engineering plastics with poor aging resistance.  Over time, the blade roots may lose strength, leading to the blades flying off while rotating at high speeds, posing a significant risk of accidents.  Moreover, the rotating blades along the roadside can distract drivers’ attention, creating safety hazards.

System lifespan:

The crucial component of wind-solar hybrid street lights is the battery used for energy storage.  Lead-acid batteries start to deteriorate after about two years, and replacing them incurs high costs.  Consequently, many wind-solar hybrid street lights, installed at a considerable expense by the government, end up as abandoned waste and are eventually replaced with conventional street lights.

Inconsistent lighting performance:

Wind-solar hybrid street lights rely on different wind and solar resources, resulting in significant variations in power generation among different systems.  As a result, it is challenging to ensure consistent lighting for each street light.

Maintenance difficulties:

Each street light operates as an independent power generation system, and different manufacturers’ wind power systems are incompatible.  This makes it practically impossible for street light management departments to maintain wind-solar hybrid street lights effectively.  During the warranty period, maintenance relies mainly on the manufacturers, but once the warranty expires, there is often no one responsible for maintenance.  Therefore, it is difficult to find successful cases of long-term stable operation.

Recommendations for the Development of Small Wind Turbines:

1、Redefine and standardize the rated parameters of small wind turbines.

2、Strengthen research on technical standards and safety requirements for small wind turbines.

3、Government agencies should leverage their expertise and establish unified design and testing standards for manufacturers to adhere to.

4、Emphasize the performance and safety of small wind turbines at low wind speeds during the design process.

5、Develop suitable electronic controllers that can protect the wind turbines and improve their efficiency.

6、System design should consider the integration of small wind turbines with control equipment and electrical devices to achieve high reliability, efficiency, low cost, easy installation, and minimal maintenance.

Summary:

Small wind turbines, as clean energy products, have vast market potential with the increasing awareness of environmental protection. However, to ensure their safety and reliability, it is necessary to strengthen the formulation and research of technical standards. The government should play a crucial role in promoting industry development by establishing unified design and testing standards. Additionally, the design process should focus on the performance and safety of small wind turbines at low wind speeds and incorporate suitable electronic controllers. Ultimately, system design should consider the integration of small wind turbines with other equipment to achieve efficient, reliable, and cost-effective systems.