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Onsite albedo measurement in Tunisia

Onsite albedo measurement in Tunisia

Albedo can be defined as the ratio of the reflected irradiance (RI) to the global horizontal irradiance (GHI) received by the ground surface. It is a dimensionless value ranging from 1 (a perfect reflector) to 0 (a perfect absorber).

Basic Facts
IndustrySolar PV power plant services
ClientACWA Power
Time frame2019
Project locationFive different locations in Tunisia
Goal and Challenges
  • Assessment of design and engineering of solar PV power plant using bifacial modules based on validated albedo onsite measurements
    Albedo measurement for bankability and feasibility study
Scope of Work
  • Onsite albedo measurement according to ASTME 1918-16 standard and client requirements
  • Four different points for each site chosen representing different terrains.
  • Measurement taken for one and half day for each site.
  • Measurement done at different heights of 0.50m,1.00m,1.50m and 2.00m simulating possible models for PV modules onsite.
  • Data filtration and correction conducted on the measurement for more accurate and representative mean albedo value for each site.
  • Graphical representation of filtered and corrected data of GHI, RI and albedo during day for each point
  • TÜV Rheinland detailed report on onsite Albedo for accurate and bankable PV system design in English and French.
  • Validation of measured data compared to satellite data
  • Determination of diffused irradiance for each measurement.
  • Analysis on different terrains/soils to provide minimum and maximum albedo limit values
  • Extrapolation of measured data to determine monthly mean albedo values for typical meteorological year (TMY) using accurate satellite database while factoring in the Albedo onsite results
  • Determination of uncertainty level of onsite measured and extrapolated data

The albedo value depends on many factors such as ground surface properties, surface homogeneity, spectral and angular distribution of solar radiation reaching the ground. These factors varies with the geographical location and time. Hence, the albedo value varies both through the year and over the years.

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