How photovoltaic manufacturers and asset owners can evaluate dust buildup, cleaning and energy yield.
An anti-soiling coating for solar panels is a surface treatment designed to change how dust, water or other deposits interact with the module glass. It can be worth evaluating where soiling reduces the light that reaches the cells or makes cleaning costly. The business case depends on the climate, the glass construction, the cleaning schedule and how long the surface retains its properties in service. [1]
Nanize develops PFAS-free polysilazane coatings and identifies renewable energy surfaces, including solar module glass, as an application area. A module maker could evaluate a coating during manufacture. An asset owner could evaluate it in collaboration with the module supplier and a qualified test partner. Both need an optical reference and evidence that any benefit holds up through the site’s actual weather and maintenance. [2] [3]
Why Solar Panel Soiling Matters
IEA PVPS reported that cumulative global installed photovoltaic capacity reached 2.96 TW at the end of 2025. The installed base spans desert plants, coastal sites, agricultural areas and rooftops. At any one site, the balance between sunlight, surface deposits and natural or scheduled cleaning influences how much of the available light reaches the cells. An effective response depends on the conditions at that site. [4] [1]
Soiling can include mineral dust, pollen, salt or other material from the surrounding environment. A thin, widespread deposit can reduce light transmission. A localized deposit may change the way light reaches part of a module. The distribution can vary across a site, with wind direction, nearby activity and array geometry all affecting exposure. The cleaning team may see different deposits at different times of year.
Moisture can help remove loose material or help it adhere. The effect depends on the type of deposit and the conditions under which a surface gets wet and dries. Rain may clean one site sufficiently during part of the year, while another still requires planned maintenance. Dew, repeated wetting and periods without rain can change the behavior of particles. For a coating evaluation, the local sequence of conditions matters as much as the annual weather summary. [1] [5]
The condition of the site also changes the cost of dealing with soiling. A ground-mounted plant may have access to specialized cleaning equipment. A rooftop project may need access arrangements and coordination with building occupants. Where water is scarce, a change in cleaning frequency may have a value beyond labor. These factors make a particular site or customer segment a better starting point than an average for the entire solar industry.
How an Anti Soiling Coating Is Intended to Work
A surface treatment can change how water wets a surface or how easily a deposit releases. A hydrophobic surface tends to resist wetting by water. A hydrophilic surface promotes spreading. These are different behaviors, and either can be relevant in a design depending on the type of deposit, surface geometry and how the site is cleaned. What matters commercially is the measured effect on the module and the maintenance program. [1]
A high contact angle may be useful evidence about water behavior on a sample. A test of dust accumulation, transmission or cleaning effort answers a different question. Droplets can behave differently after the glass has aged or accumulated residue. Compare how treated and reference surfaces perform through the conditions the module will actually experience, including the current cleaning method.
Nanize describes coatings for renewable energy surfaces with hydrophobic and low-friction properties. Its platform uses polysilazane formulations that can cure into a durable, ceramic-like film on compatible substrates. The company publishes rapid cure data from selected metal samples. A glass and module partner would establish the application conditions and assess the finished optical stack on the glass used in its product. [2] [3]
The finish needs to preserve the value of the glass it is applied to. Many projects already specify optical features on the front surface. An anti-reflective treatment is designed to address reflection. An anti-soiling treatment is evaluated for the way deposits accumulate or release. A project involving both functions needs data for the combination, including what happens to transmission, appearance and adhesion after exposure.
What a Solar Module Manufacturer Should Measure
Begin with the module maker’s current glass construction. A laboratory can compare a coated sample with the reference for transmission, reflection, haze and appearance. The test should use representative thicknesses, underlying surface treatments and production conditions. The buyer can define an optical acceptance range to preserve initial performance while it measures improvements in cleaning on the finished module glass.
Measure durability after relevant environmental and maintenance exposures. A test plan can include weathering, abrasion, cleaning chemistry and repeated wetting where those conditions reflect the intended site. A surface that performs well on a new sample may change after extended exposure. Repeat the optical and cleaning measurements after the test to find out which properties persist.
An inline application also needs production evidence. A glass supplier can assess coverage across the sheet and repeatability across lots. The module manufacturer can determine whether it wants the treatment applied before or after another manufacturing step. Handling, storage and transport can introduce contact with materials the finished surface will never see in the field, and those stages can affect the appearance of a new coating.
IEC 61215-1 describes design qualification requirements for terrestrial PV modules. A change to the glass or coating system should be reviewed with the module maker and the parties responsible for its qualification. The relevant review depends on the product and the proposed change. Testing a coated coupon can help select candidates before the team decides what module-level evaluation is appropriate. [6]
How to Design a Field Trial for a Solar Farm
Start with the site question. The operator may want to reduce soiling losses, reduce the effort needed to clean or keep transmission stable through a particular season. Choose the outcome before selecting the test location. A clear aim helps the team decide what to monitor and how long the trial needs to run to cover representative conditions.
Use comparable treated and reference surfaces. An operator can work with a laboratory and module supplier to design a comparison that accounts for module type, orientation, site conditions and the maintenance schedule. A clean reference or another suitable measurement method can help separate the effect of deposits from changes in sunlight and temperature. IEC 61724-1 provides a framework for PV performance monitoring and includes treatment of soiling measurement. [7] [5]
Record what happens around the measurements. A dust event, rain, change in cleaning, outage or shading can influence the result. Keep a dated log of cleaning and environmental events and record where the reference and candidate are located. That information can help explain why a result changes over time and whether the effect is likely to apply across the rest of the plant.
Compare several points in the service cycle. Measuring shortly after cleaning answers a question about initial condition. Measuring after deposits accumulate shows the rate at which performance changes. Measuring again after cleaning gives evidence about how readily the surface returns to its reference condition. These observations help an operator decide whether the benefit is in slower soiling, easier cleanup or a combination of the two.
A candidate surface can also be checked at the end of the trial. Inspect representative pieces for wear, changes in appearance and evidence of cleaning damage. A field trial is most useful when the team can relate any performance change to the condition of the surface. Retaining records of the coating and glass grade makes it easier to repeat the evaluation on another module or at another location.
Agree in advance how the team will handle missing observations. Weather disruptions, inverter outages and unscheduled maintenance can leave gaps in the record. A written rule for which days are comparable makes the evaluation easier for partners to review and helps prevent an unusual event from carrying too much weight in the comparison between the candidate and its reference.
Where a Coating Might Fit Into Cleaning Strategy
Solar panel cleaning decisions depend on the site’s layout, access, labor and expected value of recovered energy. Some operators clean on a schedule. Others use performance or soiling measurements to decide when a clean is worthwhile. An anti-soiling coating can be evaluated alongside either approach. A trial can ask whether it changes the interval between cleanings or the effort required to reach the same result.
If the site uses mechanical cleaning, the supplier and operator can agree on a test that reflects how the machine contacts the glass. If it uses wet cleaning, the comparison can include the liquids and methods permitted by the module maker. Each operator can use its existing maintenance method as the reference. That gives the buyer a way to judge whether the new surface fits the equipment and service arrangements already in place.
Retrofitting installed modules raises additional questions about warranty, site access, process control and how the surface can be prepared under field conditions. Work through those issues with the module supplier and qualified site personnel. A manufacturer-applied coating and a field treatment are separate supply routes with different evidence needs. A coupon study can inform a field project before any decision about a change to operating modules.
A rooftop buyer may place special value on maintenance access. If a building needs access scheduling or temporary restrictions for cleaning, the trial can include the cost of arranging the visit as well as the cleaning itself. A utility-scale site may put more weight on water use, equipment time or the amount of generation recovered. The same coating can face different purchasing decisions across those segments.
How Climate Changes the Question You Should Test
At a dry, dusty site, the operator may want to know how quickly output declines between scheduled cleans. Compare the candidate and reference through a period that includes ordinary accumulation as well as any dust events that materially affect the asset. Look at cleaning effort and the condition of the surface afterward. The value of a coating will depend on both the measured difference and how much of the site shares those exposure conditions.
At a temperate rooftop, pollen, local activity and seasonal rainfall may be more important than a long dry period. A short trial in a rainy month can show how the surfaces behave through frequent wetting. A buyer who is considering the coating for a property portfolio will also want to know whether the same result holds during the season when deposits are most persistent.
A coastal or industrial setting can present different residues and cleaning requirements. An operator can document what the maintenance team actually removes and how it is removed. The laboratory can then select an exposure that represents the application, instead of using a generic dust test alone. Repeating optical and adhesion measurements after those exposures makes the result more useful to the glass and module suppliers.
Consider location within the installation. Edges of a plant may see different exposure from the center. A rooftop near trees may be affected by shade or debris that changes over the year. Placing reference and treated samples in comparable positions helps a team interpret the differences. If there is significant variation across the site, consider which locations best represent the planned purchase.
The decision to run a trial can begin with existing records. Look for periods in which cleaning recovered output or required unusually costly maintenance. A site with an already manageable soiling pattern may have less room for improvement than a site with frequent cleaning or costly access. The operator can use that information to decide where a material trial is most likely to answer a question worth pursuing.
How to Estimate the Economics of an Anti Soiling Coating
An illustrative plant delivers 100 GWh per year and uses $40 per MWh as the value of incremental generation. If a well-controlled trial supported an improvement equivalent to half a percentage point of annual energy, that would represent approximately 500 MWh, or $20,000 at the assumed price. That calculation shows how an operator could translate a small measured change into a business estimate. The inputs are hypothetical and the real value depends on the site and contract.
Cleaning changes can be added separately where the trial supports them. If the operator can omit one $15,000 cleaning and still realize the estimated energy benefit under the revised schedule, the combined gross value in the example would be $35,000. The operator should model the two outcomes together because changing the schedule also changes the soiling that occurs. A good model uses the same scenario for the cleaning and energy assumptions.
Then account for the cost of the coating, its application, any additional inspection and how often it needs renewal. Consider whether the benefit holds through different seasons and how confidently it can be extrapolated to other blocks. A long-lived change may justify a different investment from a short-lived one. Sensitivity to performance and service life often tells the buyer more than a single payback number.
Keep the economics close to the party that pays. A glass supplier may need to understand the cost per square meter of coated glass. A module brand may need to understand warranty and manufacturing implications. An asset owner may need the value per megawatt or per site. Agreeing on those units early helps each partner see whether the expected improvement can support its part of the business case.
Turning a Trial Into a Procurement Specification
Specify the glass construction and coating together where practical. A buyer can identify the current surface, the acceptable optical range and the cleaning methods permitted in service. If the product already has an optical treatment, require comparable data for the proposed combined stack. A named glass and coating grade make it easier to interpret the evidence and repeat the evaluation on later lots.
Record the conditions that support any performance claim. A result after one season at a particular site belongs beside its climate, maintenance schedule and measurement method. A laboratory result belongs beside the substrate and exposure used in the test. A procurement team can use both to define an application range and identify where the supplier needs to provide more evidence.
A service plan also benefits from a defined trigger. Agree who will inspect the coating, what will be recorded and when the operator will review the cleaning schedule. If the treatment needs renewal, include the time, access and cost in the comparison. A simple plan for confirming performance after installation gives the buyer a way to tell whether the benefit modeled at purchase persists.
For module suppliers, agree how changes are handled after qualification. A change in glass, an underlying optical treatment or the coating process could change the result. Keep records that identify the versions evaluated and the criteria used to release the finished product. That information helps a manufacturer protect the value of the original testing and gives the customer a clear basis for discussing new applications.
The Nanize Team and Solar Industry Partners
CEO David Hogg brings a background in solar manufacturing and industrial technology commercialization, including past leadership at Suntech and Innotech Solar. Chief Commercial Officer Jerry Stokes previously led Suntech Europe and is a Senior Advisor to the Global Solar Council. Those backgrounds are relevant when a coating project has to connect materials, module manufacturing and asset operation. [8] [9] [10] [11]
Dr. Kingsley Iwu and the technical team develop and evaluate coating formulations. Håvard Lillebo, CFO and co-founder, brings the finance perspective to development and scale-up. For a solar trial, a glass supplier can help define the substrate, the module maker can set optical and qualification requirements, and an operator can identify the maintenance conditions that give the evaluation practical value. [8] [2]
Frequently Asked Questions About Solar Panel Coatings
Is an anti soiling coating the same as an anti reflective coating
An anti-reflective treatment addresses light lost through reflection. An anti-soiling treatment is designed to change how deposits interact with the surface or how easily they release. Both can affect the optical behavior of a finished glass system. A supplier proposing a combined stack should provide data for that stack on the intended glass.
Can rain make a solar panel self cleaning
Rain can remove some deposits under some conditions. The outcome depends on the contaminant, the surface, weather and array geometry. A comparison that includes periods of both rain and dry weather provides more information than a demonstration with a single drop of water. The cleaning plan can then reflect the observed behavior at the site. [1]
How much more electricity could an anti soiling coating produce
Start with the site’s current soiling losses and a credible comparison. The potential improvement depends on how much of that loss the coating changes and how long the effect lasts. A field evaluation can estimate the difference in normalized performance between treated and reference modules. Any projection should state the assumptions, climate and maintenance schedule used.
Can a coating be tested on modules already in service
An owner can discuss a controlled evaluation with the module manufacturer and qualified site personnel. Review the warranty, glass construction, existing surface treatments and maintenance procedures before choosing a method. A test on representative glass or modules can help decide whether a field evaluation is appropriate.
Does hydrophobic glass always need less cleaning
Water repellency is one surface characteristic. Cleaning frequency depends on the deposits that form and the performance the operator wants to retain. Measure dust accumulation, cleaning effort and optical or electrical performance before and after use. Those data are the basis for changing the cleaning schedule.
Discuss a Solar Glass Project With Nanize
Nanize is looking for module makers, glass suppliers, asset owners, coating equipment partners and investors interested in a measurable solar surface project. Event organizers can also discuss panels or technical sessions on solar manufacturing and operations. Contact Jerry Stokes at js@nanize.com with the module construction, target climate and current maintenance question. [12] [8]
Sources
1. IEA PVPS report on soiling losses and mitigation
2. Nanize coating applications
3. Nanize coating technology and test results
4. IEA PVPS Trends in Photovoltaic Applications 2026
5. IEA PVPS fact sheet on measuring and mitigating soiling
6. IEC 61215-1 for terrestrial PV module design qualification
7. IEC 61724-1 for PV system performance monitoring
8. Nanize executive team and business contacts
9. Suntech executive appointments and biographies
10. Innotech Solar announcement of David Hogg as CEO