With the growth in solar energy around the world, ensuring photovoltaic (PV) systems are operating efficiently has become a key issue for operators and home owners. A common question is, can solar panels be washed with water? The answer is yes, although some consideration is need in the manner in which they are washed, water usage, and environmental impact. Here is a detailed summary based on industry practices, technological developments
and environmental studies.
The Need for Regular Cleaning
Dust, bird droppings, pollen, and industrial debris are among the various contaminants that can accumulate on solar panels. These are contaminants that can impede the transmission of light and lead to decreased energy output, lowering performance levels. The amount of degradation turnover varies from 5% to 30%, problems vary depending on the environment, and regular cleaning is essential for optimal performance.
Water-Based Cleaning: Methods and Best Practices
Water is a primary resource for cleaning PV panels, but its application varies:
Manual Cleaning: Using gentle-brushing and spraying with water is an effective method for smaller systems. The downside is that if you are using hard water for rinsing, you will be left with mineral deposits afterwards, so you may want to limit yourself to using purified/deionized water for rinsing, and leave it that way to avoid the streaks.
Automated Cleaning Systems: Larger solar farms typically use robotic cleaner systems or fixed sprinkler installations that can dispense a high-velocity water jet under pressure. These automated systems may appear attractive due to their high-efficiency, however, they can also leverage large quantities of fresh water. For example, a domestic cleaning method can make approximately 63% of total water consumption when cleaning a PV station.
Water Recycling: New technologies such as rainwater catchment and filtration technology reduce the need for new fresh water for cleaning glass panels. For example, some systems use take-type water storage tanks that catch and store rainwater to reuse when cleaning glass panel surfaces to reduce waste.
Environmental Concerns and Solutions
While water cleaning is effective at cleaning, it comes with a set of challenges with using your own resources related to water use:
Water Scarcity:
In dry climates, excessive water use is not sustainable.
Chemical Runoff:
Some cleaning products contain chemicals that can adversely impact ecosystems if they are not properly managed.
To alleviate these problems:
Eco-Friendly Cleaners:
Biodegradable cleaning products that are non-toxic are plentiful these days. Non-toxic cleaning products avoid heavy metals, phosphorus, and various other toxic materials, and they also meet international standards such as EU Rohs.
Waterless technologies:
Robotic technologies that use microfiber customer rollers and airflow systems remove water altogether. These robots even help prevent soil contamination by washing down materials. An example is in the Atacama Desert in Chile, in which the robots assist in saving each unit 1.2 million liters of water monthly.
Technological Advancements
Smart cleaning systems integrate real-time monitoring to optimize water use:
IoT-enabled solutions: For photovoltaic systems, the soiling levels on photovoltaic modules can be determined from current-voltage curves and the corresponding power output levels can be estimated. After determining soiling levels, etc., traveling can be flagged based on the data outputs, e.g., losses in efficiency, changes of the short-circuit current, etc., and determine if the module needs to be cleaned mechanically or with water.
FV-PV systems: Floating solar farms can reduce freshwater use through automated sprinklers that spray water from the lake or reservoir. However, in terms of technology, floating solar development is limited from a technical perspective due to filtration processes for floating penstocks or submerged pipeline for eliminating algal growth or debris that can clog sprinkler systems.
Conclusion: Striving for Efficiency and Sustainability
Though water continues to be a feasible cleaning agent for solar PV, its utilization must change. The leadership organization recommends the following best practice approaches:
Using recycled water or incorporating collected rainwater.
Using environmentally sustainable detergent (and other agents) for persistent grime.
Using waterless robos in areas where water availability is low.
As the industry moves towards full lifecycle sustainability, the collaboration with these practises ensures that solar energy can remain a truly green energy source.
