The Albedo Concept in solar panels

Solar panels use photovoltaic cells to absorb incident radiation to generate alternating current. The same solar panels reflect some of the radiation. These reflected radiations are going wasted. Making use of these reflected radiation would increase the efficiency of the solar power system. Manufacturers and customers should be aware of the Albedo in solar panels. The solar panels have a high diffusion rate of the incident solar irradiation.

Measuring the Albedo Effect

The Albedo in solar panels is measured by an albedo-meter. The instrument indicates the radiation reflected on a given surface. The albedo-meter has two pyranometers:

  • One focusing downwards to the surface of solar panel.
  • The second pyranometer facing vertically upwards.

The process of incidence and reflection of the light over solar panel provides an estimate of the albedo effect.

Albedo in Solar Panels

Albedo in Solar panels usually convert 16.67% of the incident radiation to direct current. The rest is dissipated as heat. Albedo measures the diffused and reflected solar radiation incident from any astronomical body.

The range of the albedo is the zero to one. It is a ratio, a dimensionless fraction. The Albedo fraction depends on the nature of the surface where the solar panel is installed. For instance, asphalt has a different albedo from the snow. Undoubtedly, this is because Asphalt is a dark recipient, while snow is a light-coloured one. Albedo in solar panels with zero ratio absorb over 90% of the incident radiation. Such is desirable since an albedo of one implies very high reflecting of the panel.

The Efficiency of Albedo in Solar Panels

Let us assume a black solar panel with a 16% efficiency. That means that for every kWh of electricity generated, the energy falling on the panel is 6 kWh obtained from (1/16*1kWh). Of this, 5kWh is radiated as heat while the remaining 1kWh creates electricity. The effect of albedo values reflection of a tilted solar panel is presented below. From the image, it is clear that Albedo in Solar Panels is most significant during noon; hence, changing it is crucial in areas where snow is present.

Schermata-2019-12-30-alle-15.05.19 Albedo in Solar Panels Amerisolar Blog News  Effects of Albedo on the Reflection of Solar Radiation (PVMC, 2019)

The adoption of bifacial solar panels increases energy output since sun rays are collected on both sides of a panel. High diffusivity and high reflectivity of solar radiation increase efficiency.

Factors Affecting Albedo in Solar Panels

At the same time, the efficiency of Albedo in solar panels is affected by factors like:

  • Ageing: which affects the effectiveness of the PV cells.
  • Cloud intensity: It absorbs some of the incident radiation.
  • Rain: It reduces the irradiation rate.
  • Solar altitude: It affects the radiation incident on the panel.

The estimation of albedo is not only crucial in solar panels but also in the energy efficiency sector, specifically in the newly invented energy-invented buildings.
Therefore, the albedo effect is not negligible, and it should be taken into account when considering the pay-back period of solar power system.