Tokyo, March 5, Dai Nippon Printing Co., Ltd. (DNP) has commenced the supply of DNP reflective sheets for solar power plants, which improves power generation output in bifacial solar cell modules. The newly offered product is a sheet that is laid on the ground surface at power plants where photovoltaic modules that generate electricity by receiving light on both faces are installed. Improving the reflective ability of sunlight, referred to as Albedo, increases the amount of light that enters the rear side of the module, which has the effect of boosting power generation.

We have been conducting demonstration tests at a solar power plant in Asahikawa City, Hokkaido since 2020, and have confirmed that the effect of the sheet boosts power generation by approximately 6%. We have also confirmed that the system maintains performance even three years following installation. 

DNP reflective sheets for solar power plants

Image of sheet installed on ground surface

[Developmental Background]

With the aim of spreading and developing renewable energy, in 2012 the Japanese government introduced a Feed-in Tariff (FIT) system, under which power companies purchase electricity generated from renewable energies, such as solar and wind power, at a fixed price for a set period of time. The applicable period is 10 years for solar power generation with a capacity of less than 10kW, and 20 years for solar power generation with a higher capacity. 

The number of power plants that have been in operation for around 10 years is increasing, and related equipment upgrades is rising. As a result, Repowering is being implemented to increase power generation by introducing new bifacial photovoltaic modules. Repowering has been defined as the process of replacing older power stations with newer ones that either have a greater capacity or higher efficiency, resulting in a net increase of power generated. 

In response to these needs, DNP has commenced supply of DNP reflective sheets for solar power plants, leveraging its track record of providing back sheets and encapsulants for solar cell modules with high durability and reliability. The sheet is a product that improves the power generation output of bifacial photovoltaic modules, and has been developed based on converting technology that combines a variety of materials and reliability assessment technology.

[Features]

1.Increase power generation with high light reflectance of more than 85%  

The sheet has a high reflectance in excess of 85% for light wavelengths of 400nm to 1,200nm, which is the power generation range of solar cells. It maintains a high light scattering effect, so can accommodate a wide range of angles of sunlight. In addition, the sheet does not contain any metal layers and is electrically insulating, so you can use it with confidence. 

Also, unlike the uneven surfaces of woven or non-woven fabrics, this product has a smooth surface, so it is less likely to attract dirt or mud, and exhibits excellent stain resistance. As a result, it is possible to count on a continuous improvement in power generation without reducing the reflectance of the sheet over an extended period.

2.Durability equivalent to 10 years of outdoor service life1

In high temperature/high humidity resistance tests and weather resistance tests used to evaluate the reliability of solar cell modules, there was no change in reflectance even after 10 years of outdoor service, and the power generation improvement effect was maintained. In addition, there is no deterioration in mechanical strength , meaning the sheet maintains high wind resistance over an extended period of time. 

3.Weed-proof effect due to high light blocking properties 

The sheet can block more than 90% of the light wavelengths that plants use for photosynthesis. As a result, it can prevent plant growth by suppressing the transmission of light to the ground surface where the sheet is laid. Doing so, leads to a reduction in the burden of weeding work.

[Going Forward]

DNP will provide the sheet to power generation companies considering the introduction of bifacial photovoltaic modules, Engineering Procurement and Construction (EPC) companies, and  Operation & Maintenance (O&M) companies, aiming for cumulative sales of 5 billion yen by 2025. Going forward, DNP will continue to contribute to the realization of a sustainable society through products that lead to the spread and expansion of renewable energy.

 1: Test results are approximations of service life only, and actual service life may vary depending on the environment in which the product is used. DNP provides no guarantee of actual service life.

* Company and products names mentioned in this release are the trademarks or registered trademarks of those companies

* Product specifications and service details referred to in this news release are current as of the date of the announcement. They may be changed without notice.