PT        EN
logo Minit�rio de Minas e Energia
logo Eletrobras

Solar Potencial - SunData

Last modified: 30.01.2015

The SunData program is intended to calculate the monthly average daily solar radiation anywhere in the country and is an attempt by CRESESB to offer a support tool for sizing photovoltaic systems. It has been used in the design of systems in various stages of PRODEEM.

Incident solar radiation (sunlight) database

The SunData program is based on the database Valores Medios de Irradiación Solar Sobre Suelo Horizontal of the Centro de Estudios de la Energía Solar (CENSOLAR, 1993) containing values of monthly average daily solar radiation on the horizontal plane for about 350 points in Brazil and neighboring countries.

Other solarimetric consolidated database available in Brazil:

Search by Coordinates

The system for the search of nearby locations is done by the geographical coordinates (latitude and longitude) of the point of interest. If the city of your interest is not listed, you should select the nearest location suggested by the search or with the most similar features to the one of your interest. The numeric input format of the geographic coordinate can be in decimal degrees (00.00°) or degrees, minutes and seconds (00°00'00"), according to the option selected in the form.

The program provides essential solar radiation data for at least 3 locations available near the point of interest. Values of solar radiation are provided in kWh/ in the horizontal plane, corresponding to monthly daily averages for the 12 months of the year.

Valid latitude values must be within the range of 12° North and 40° South and longitude values between 30° West and 80° West.

Calculation of Irradiation on Inclined plane

For each of the three selected locations, there is also the provision of values of solar radiation converted from the horizontal into inclined planes with three different angles of inclination to the horizontal plane:

  • the angle that is equal to the latitude;
  • the angle that provides the highest daily average of solar radiation p.a.;
  • the angle that provides the highest minimum daily value of solar radiation p.a.

These inclinations are only suggestions for the installation of photovoltaic panels. The choice of these inclinations depends mainly on the main activity of the installation and the project requirements, e.g. domestic, tourism, industrial, etc. In general, the value of the local latitude is used as inclination angle of the PV module. The angle with the highest daily average of solar radiation p.a. is usually used when you want the highest annual energy generation, which would be the case for photovoltaics applications connected to the distribution network within the Power Compensation System, defined by Aneel's Normative Resolution N° 482/12. As for the angle with the highest minimum monthly value of solar radiation, it is usually a conservative measure, used in situations where continuous supply of electricity is critical for the main activity and so we seek to minimize the risk of power outages.

The values of solar radiation are just guidelines to assist in the PV system, as it consolidated values of a measurement history ranging over the years. The amount of solar radiation depends on the location where you want to install the system.

The three sets of values show the monthly daily average radiation for the three inclinations: Latitude, Higher Average and Highest Minimum, with the following comments:

  • angles of inclination are rounded to integer values of degrees, depending on the accuracy of inclination measuring instruments used for the instalation of photovoltaic systems in field, called a goniometer, which often presents errors of the order of a few degrees;
  • the minimum inclination allowed is 10°, as CEPEL does not recommend the installation of photovoltaic panels below this inclination to prevent the accumulation of water and dirt;
  • the inclination angle B, sought by each criteria of Latitude, Higher Average and Higher Minimum is calculated in the range of: Latitude - 20 = B = Latitude + 20, in steps of 1 degree;
  • the guidelines of the PV modules are also given, being admitted only orientation in the North direction (indicated by N) or South direction (indicated by S).

The conversion of radiation in the horizontal plane for the inclined planes is calculated according to the isotropic method of Liu and Jordan (1962) extended by Klein (1977).

Presentation of Data

The data are presented in the following format:

Latitude: XX,XX° N|S
Longitude:XX,XX° O
Distance from the reference point. (XX.XX° N|S; XX.XX° O): XX.X Km
 Average daily irradiation [kwh/]
AngleInclination [°]JanFebMarAprMayJunJulAugSepOucNovDecAverageDelta
Angle equal to latitude XX X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx
Highest annual average XX X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx
Highest monthly minimum XX X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx X.xx

The title of the table shows the name of the city, the State (or country it belongs to, if not Brazil), its geographic coordinates, and distance (km) in a straight line from the point of interest searched.

The data in the table shows the monthly daily average of solar radiation (kWh/ for all months of the year, as of January.

Additionally, it shows the value of the lowest monthly daily average of irradiation ( Minimum), the highest monthly daily average of irradiation (Maximum), the daily average of irradiation p.a. (Average) and the difference between the maximum and minimum (Delta).

About Sundata

  1. CENSOLAR, 1993. Valores Medios de Irradiacion Solar Sobre Suelo Horizontal - Centro de Estudos de la Energia Solar. Sevilla.
  2. Duffie, John A., Beckman, William A., 2006. Solar Engineering of Thermal Processes. ISBN: 978-0-471-69867-8, 3 ed. John Wiley and Sons, New York, USA, 928 p..
  4. Guimarães, Ana P. C., 1995. Estudo Solarimétrico com base na definição de mês padrão e sequência de radiação diária. Dissertação de M.Sc., Departamento do Engenharia Mecânica, EE/UFMG, Rio de Janeiro, Brasil.

SunData 2.0

  • Authors:
    • Ana Paula C. Guimarães
    • Marco A. Galdino
  • Adaptation:
    • Bruno Montezano

SunData 1.0

  • Authors:
    • Marco A. Galdino - CEPEL
    • Cristiane M. Gomes - CEPEL
  • Adaptation:
    • Alberto A. Kopiler - CEPEL
    • Ricardo M. Dutra - CRESESB

Show all pages

 °   '   "
 °   '   " West

decimal degrees (00.00°)
degrees, minutes and seconds (00°00'00")
I. Valid latitude values must be in the range of 12° North and 40° South and longitude values between 30° West and 80° West.
Should there be any doubts, please contact us.

CRESESB - Reference Center of Solar and Wind Energy / CEPEL - Electric Power Research Center
Av. Horácio Macedo, 354 - Cidade Universitária - Rio de Janeiro - RJ - Brazil, CEP 21941-911
Tel: 55 (21) 2598-6174 / 2598-6187 - Fax: 55 (21) 2280-3537 - E-mail:
(Monday to Friday, from 8:00 to 16:30 - (UTC-03:00) Brasília)

Webdesign: Bruno Montezano, 2014