1. Impact of Temperature on System Performance
1.1 Effects on Solar Cells
- Open Circuit Voltage Decrease: As temperature rises, the open circuit voltage of solar cells decreases. For example, for crystalline silicon solar panels, when the junction temperature exceeds 25°C, the open circuit voltage decreases by approximately 210-212 mV for every 1°C increase.3
- Short Circuit Current Increase: The short circuit current of solar cells may slightly increase with higher temperatures, although the increase is minimal.79
- Maximum Power Decrease: Higher temperatures significantly lower the maximum power output of solar cells; typically, a 1°C increase in temperature results in about a 1% loss in output power.
1.2 Effects on Batteries
- Capacity Variation: Battery capacity fluctuates with temperature. At lower temperatures, capacity increases with rising temperature; however, at high temperatures, capacity decreases and lifespan shortens.
- Float Life Reduction: For every 10°C increase, the float life of batteries is reduced by approximately half. High temperatures accelerate issues such as water loss, thermal runaway, corrosion, and deformation of positive plates, affecting battery lifespan.
- Increased Self-Discharge Rate: Higher temperatures result in higher self-discharge rates for batteries; thus, it’s essential to avoid long-term storage of batteries in high-temperature environments.
2. Effects of Sunshine Hours and Radiation Intensity
2.1 Sunshine Hours
- Increased Generation: Longer sunshine hours equate to more light received by solar batteries, leading to higher power generation. For instance, Xinyu County boasts over 190 hours of average annual sunshine, peaking above 200 hours between March and June, hitting a maximum of 264.1 hours in May.
- Increased Utilization Hours: More sunshine hours directly enhance the daily utilization hours of the system, highlighting a significant positive correlation between the two. The increase in sunshine hours allows the system to charge for longer, improving overall efficiency.
2.2 Radiation Intensity
- Increased Output Power: The intensity of solar radiation directly affects photovoltaic generation. Higher radiation intensity leads to higher output power from solar cells. For example, the annual total radiation in Dunhuang is 6882 MJ/m², with an average daily radiation of 18.86 MJ/m², making it one of China’s solar resource-rich areas.
- Multi-Peak Power Issues: Frequent changes in environmental factors can cause the system to produce multi-peak power, affecting the iteration precision of maximum power point tracking (MPPT) algorithms and thus impacting system output power. Therefore, solar energy storage systems are more suited for environments with stable temperature and radiation intensity.
3. Impact of Relative Humidity
- Photovoltaic Power Variation: Relative humidity significantly influences photovoltaic power. For every 1% decrease in relative humidity, the photovoltaic power increases by 27.35 kW. Conversely, a 1% increase in humidity results in a 27.35 kW decrease in power. This indicates that solar energy storage systems perform better in dry climate conditions.3
4. Effects of Wind Speed
- Heat Dissipation: Adequate wind speed can dissipate heat from photovoltaic panels and batteries, lowering surface temperatures and enhancing power generation efficiency. However, excessively high wind speeds may cause mechanical damage or other issues that need to be accounted for in design.
- Dust Control: Higher wind speeds can reduce dust accumulation, improving the cleanliness of photovoltaic panels and thus raising power generation efficiency. Conversely, lower wind speeds are more conducive to dust buildup, diminishing the transparency of panels and affecting output.
5. Impact of Dust Accumulation
- Shading Effects: Dust accumulation can obstruct photovoltaic panels, reducing light exposure and lowering system output. The mechanisms of dust impact on photovoltaic efficiency include shading and optical loss effects.
- Cleaning Maintenance: Regular cleaning of photovoltaic panels is an important measure to enhance system performance. Especially in dry and dusty environments, consistent cleaning can significantly boost panel transparency and generating efficiency.
- Anti-Dust Coatings: Applying anti-dust materials to the surface of photovoltaic panels can reduce dust adherence, thus slowing accumulation rates.
6. Comprehensive Mitigation Strategies
6.1 System Design
- Heat Dissipation Design: Using efficient thermal materials and techniques in the design of photovoltaic panels and storage systems, such as adding heat sinks and applying thermal conductive grease, can lower temperatures.
- Shading Measures: During hot summer periods, measures like shading nets or panels can reduce direct sunlight on photovoltaic panels, lowering surface temperatures.
- Wind Protection Design: In high wind-speed areas, wind-resistant designs such as strengthening support structures and using wind-resistant materials can prevent damage to panels and storage equipment.
- Moisture Protection Design: In high humidity areas, using sealed battery boxes and moisture-resistant materials can prevent performance degradation and equipment damage from excessive humidity.
6.2 Operational Management
- Multi-Weather Operational Strategy: Establish appropriate operational strategies based on different weather patterns (sunny, rainy, cloudy, etc.). For example, prioritize solar panel generation and charging on sunny days, while reducing solar panel generation and increasing storage system discharge on rainy days to ensure stable operations.
- Day-Ahead Planning and Daily Adjustments: Plan the next day based on weather forecasts to choose suitable operational strategies. During daily operations, implement rolling adjustments using short-term photovoltaic power prediction technology to optimize operational costs and economics.
- Redundancy Design: Incorporate redundant capacity in system design to handle extreme weather conditions, enhancing reliability and stability.
6.3 Technological Optimization
- Improve MPPT Algorithms: Develop MPPT algorithms that adapt to multi-peak power scenarios to enhance iteration precision in frequently changing environmental conditions, thereby increasing output power.
- Intelligent Control Systems: Implement intelligent control systems, such as machine learning-based strategies, to monitor and adjust operational parameters in real-time according to various climate conditions.
- High-Performance Storage Materials: Research and utilize high-performance storage materials, such as high energy density batteries and high power density supercapacitors, to enhance overall performance and adaptability of storage systems.
7. International Case Studies
7.1 Automatic Cleaning Systems in Saudi Arabia
- Background: Located in a desert area with severe sandstorms, photovoltaic panels in Saudi Arabia easily accumulate dust, significantly affecting generation efficiency.
- Solution: Some large photovoltaic plants in Saudi Arabia have adopted automatic cleaning systems based on dry and hybrid methods. These systems are equipped with track rollers that can move freely between solar panels for efficient cleaning.
- Effect: Tests show that the automatic cleaning system can reduce dust accumulation on solar panels by 99%, increasing power generation efficiency by over 10%. Furthermore, the system can withstand severe weather conditions like heavy rain and strong winds, ensuring continuous and safe cleaning operations.
7.2 Vehicle-mounted Automatic Cleaning Devices in Australia
- Background: Australia has extensive and sparsely distributed photovoltaic plants, and traditional cleaning methods struggle to meet the cleaning needs of large-scale solar farms.
- Solution: Some photovoltaic companies in Australia have developed vehicle-mounted automatic cleaning devices. These devices utilize water trucks as a base and employ hydraulic, motor, and worm gear mechanisms to control multiple functions such as rotating and elevating cleaning arms and brush assemblies.
- Effect: The vehicle-mounted automatic cleaning device can clean multiple photovoltaic arrays simultaneously, achieving a cleaning efficiency of 35 m²/h. The cleaned photovoltaic modules meet the operational requirements of photovoltaic generation companies, especially in dust-prone areas like Jiuquan and the northwest region, receiving positive feedback from owners.
7.3 IoT-Based Automatic Cleaning Systems in Germany
- Background: Photovoltaic plants in Germany face varying weather conditions, including sunny, rainy, and cloudy days, necessitating flexible cleaning strategies.
- Solution: Many photovoltaic companies in Germany have adopted IoT-based automatic cleaning systems. These systems consist of photovoltaic panel management nodes, IoT nodes, and upper-level applications for automatic cleaning in both automatic and manual modes.
- Effect: The system monitors real-time data such as water droplet presence, lighting levels, and cleaning device status through sensors and displays this information on screens. Users can select operational modes and set threshold values for illumination on the screen while maintaining remote control of cleaning devices via applications and servers to ensure efficient operation under various weather conditions.
8. Economic Benefits
8.1 Reduction of Economic Losses
- Improved Power Generation: Automatic cleaning systems can significantly enhance the cleanliness of photovoltaic panels, leading to higher power generation efficiency. For example, when photovoltaic components are heavily dust-laden, economic losses can reach up to 4268 yuan/day. Regular cleaning can considerably mitigate these losses.
- Lower Labor Costs: Automatic cleaning systems reduce the frequency and duration of manual cleaning, decreasing labor costs and boosting overall economic efficiency.
- Extended Equipment Lifespan: Regular cleaning can prevent localized sintering and corrosion of photovoltaic panels due to dust, thus extending the lifespan of the equipment.
8.2 Increased Return on Investment
- Higher Generation Volumes: Clean photovoltaic panels can absorb more solar radiation, thus increasing power output and enhancing the return on investment.
- Reduced Maintenance Costs: Automatic cleaning systems can lower maintenance costs associated with dust accumulation, further improving economic efficiency.
- Enhanced System Stability: By optimizing system design and operational strategies, stability and reliability can be improved, minimizing downtime and losses due to weather variability.
9. Environmental Benefits
9.1 Water Resource Conservation
- Dry Cleaning: Dry cleaning systems do not require large amounts of water, making them particularly suitable for arid and water-scarce regions.
- Efficient Water Use: Even water-based cleaning systems can optimize designs to reduce water consumption and enhance resource utilization efficiency.
9.2 Pollution Reduction
- No Chemical Pollution: Dry cleaning systems avoid the use of chemical cleaning agents, reducing environmental chemical contamination.
- Reduced Carbon Emissions: By enhancing power generation efficiency and reducing reliance on traditional energy, carbon emissions are consequently lowered.
10. Future Outlook
10.1 Technological Advancements
- New Materials: Development of new anti-dust materials and high-performance cleaning agents will further enhance cleaning effectiveness and durability.
- Smart Algorithms: Creating more advanced intelligent algorithms, such as machine learning-based cleaning strategies, will lead to more accurate automatic control.
10.2 Policy Support
- Government Incentives: Governments around the world can provide financial subsidies, tax incentives, and other policies to encourage businesses and individuals to install automatic cleaning systems, enhancing solar power generation efficiency and economic viability.
- Standardization: Establishing unified industry standards will regulate the design, production, and application of automatic cleaning systems to ensure quality and safety.
11. Conclusion
Climate conditions significantly influence the performance of solar energy storage systems. Through smart system design, regular maintenance, intelligent control, and multi-weather operational strategies, these issues can be effectively mitigated. Automatic cleaning systems not only enhance the cleanliness of photovoltaic panels, thereby improving power generation efficiency, but also reduce labor costs and equipment wear, increasing both economic and environmental benefits. This guide aims to provide valuable insights to help you better manage and optimize solar energy storage systems in practical applications.