Solar Farm - KwaZulu South Africa

Following a turbulent twelve months in the UK’s energy markets, the installed solar capacity is over 14.4 gigawatt (GW) and growing. While new installations are critical in continuing the transition to non-fossil fuels, maximising the efficiency of existing installations is of equal if not more importance, as the vast majority were installed during the ‘feed-in tariff’ boom up to April 2019.

Cleaning is important for solar installations; it is well documented that depending on the location, energy losses on panels from soiling can be upwards of 7%, and in particularly harsh environments, such as the Middle East, up to 50%. While the average losses in the UK will be at the lower end of the scale, any loss of energy transmission efficiency is a loss in revenue.

While maintaining efficiency can be achieved through cleaning, maximising the efficiency of installations against soiling can be achieved using Solar (PV) PanelGuard from Nano-Care, a single application nano-coating.

Solar (PV) PanelGuard is a silica-based nano-coating, which has an extremely durable hydrophilic performance to repel environmental dirt and pollution. The coatings’ built-in AR (anti-reflection) performance leads to increased light transmission to the panels of up to 2.5% by reducing the amount of light lost on untreated glass, which has been demonstrated to be up to 4% of the light hitting the panel at right-angles. Combined with the reduction in contamination, this will typically lead to an overall increase in energy yield of 6-7% – which allows an amortisation of the investment between 6 months and 3 years (depending on the electricity price in any regional market).

The results of an onsite trial carried out on a 146 kWp solar field with 289 modules during 2022 in KwaZulu, Natal South Africa, demonstrates these gains.

TrialPeriod 2022String 4 (uncoated)String 6 (uncoated)Difference in performance 4 to 6Uncoated/Control Panel PerformanceApril 23 – May 27 (35 days)26,299.7327,679.85 

– 4.99 %TrialPeriod 2022String 4 (coated)String 6 (uncoated)Difference in performance 4 to 6Treated Panel PerformanceMay 28 – July 1 (35 days)25,221.2424,960.651.04 %Trial ResultsComparative values drop in performance95.90%90.18%1.0635 Performance Factor

The longer-term energy sapping issue is ‘cementation’, where panels that are left ‘dusty’ for long periods, combined with regular light dews, cause the dust to become hardened on the panel and difficult to remove without abrasion (which can damage the solar cells). This can be avoided by using this hydrophilic coating which minimises losses from decreased light absorption.

The benefits of the hydrophilic non-stick nature of the coating outperform previously favoured hydrophobic coatings – which have required rainfall heavy enough to move the dust in order to be effective, and are of limited use on panels that are not at a steep enough angle for the water or dew to run-off easily.

Solar (PV) PanelGuard can be applied to panels as part of an ongoing cleaning and maintenance schedule on site before factory shipment or on-site prior to installation – giving both existing and new installations the ability to enhance energy yield by 6-7%.