Validation of Meteornom solar irradiation data for three regions in Brazil

Abstract:

This work is a part of a study to identify available and reliable sources of solar irradiation data in Brazil – with a strong focus on their relevance for PV and CSP applications. One of these sources is the Meteonorm <http://meteonorm.com/>. Meteonorm is a comprehensive meteorological reference. It gives access to a catalogue of solar radiation data and meteorological data for solar applications and system design at any desired location in the world. The current report provides an evaluation of the solar irradiation data derived from version 7.0 of the Meteonorm software for Brazil. This evaluation was made by using the observation data of horizontal global solar irradiation from the SONDA/BSRN network <http://sonda.ccst.inpe.br/> for Petrolina (PTR), Brasilia (BRB), and São Martinho do Serra (SMS). These sites were chosen based on a careful data quality control, absence of daily gaps, and less than 60% of missing data per month. The Meteonorm data were generated with real input monthly average for each selected validation sites for the years 2011, 2013, and 2014. The analysis was performed by relative and cumulative frequency of annual and seasonal solar irradiance, based on the methodology proposed by Pierre Inechen, 2006. The results showed little interannual variability for the validation sites and presented a recurrent occurrence of the value of 1000W.m^-2 for stations PTR and BRB. The Meteonorm was able to represent the high frequencies in these locations, however, presented an interannual variation greater than observed, and an overestimation of values. As for the seasonal analysis, it was possible to verify that the quarters which varied the most from one year to the next were the Dec-Jan-Feb and Sep-Oct-Nov in BRB station; Dec-Jan-Feb and Mar-Apr-May in the PTR station; and Dec-Jan-Feb in the SMS station. The Meteornorm was able identify the months of highest and lowest variability in the BRB and SMS stations, except PTR station which yielded a large variability for all quarters. Regarding the relative frequency of the clearness index, the Meteonorm overestimated the lowest values and underestimated the highest values. We concluded that the Meteonorm software it proved to be a valid alternative in pre-feasibility studies for solar energy projects in Brazil.

Supported by Petrobras contract No. 23000.0073552011-96