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Weather

Weather Data

Weather data serves as the starting point for evaluating a project.

PVsyst distinguishes between two types of meteorological data:

Monthly Meteorological Data

Monthly data files contain:

  • the site name, country, and region of the world
  • geographic coordinates: latitude, longitude, altitude, and time zone
  • monthly horizontal global irradiance
  • monthly averages of ambient temperature

Hourly meteorological data

Hourly meteorological data contain hourly values for:

  • horizontal global irradiance
  • horizontal diffuse irradiance
  • ambient temperature

Data are recorded for full days (from \(0\ \mathrm{h}\) to \(23\ \mathrm{h}\)). The hourly labels refer to the start of the interval (for example, the label \(12\ \mathrm{h}\) corresponds to the interval \(12\ \mathrm{h}\) – \(13\ \mathrm{h}\)).

PVGIS Meteorological Data

PVGIS (Photovoltaic Geographical Information System) is a research, demonstration, and decision-support tool dedicated to solar energy resources. It is part of the SOLAREC initiative of the Renewable Energy Unit at the European Commission’s Joint Research Centre (JRC), based in Ispra.

A complete description of the project is available at the following address: https://joint-research-centre.ec.europa.eu/pvgis-photovoltaic-geographical-information-system/getting-started-pvgis/using-pvgis-frequently-asked-questions_en

PVGIS provides monthly irradiation data, which must then be converted into hourly data for use in PVsystBasic.

The database covers different regions using specific methodologies:

European subcontinent

  • Geographic data:
    • digital elevation model (resolution \(1\ \mathrm{km} \times 1\ \mathrm{km}\)) for horizon assessment, derived from USGS SRTM-30 data
    • administrative boundaries
    • CORINE land cover with a resolution of \(100\ \mathrm{m} \times 100\ \mathrm{m}\), cities, etc.
  • Continuous spatialized climate data:
    • monthly global irradiance
    • diffuse/global ratio
    • air temperature

Mediterranean Basin, Africa, and Southwest Asia

  • Geographic data:
    • elevation model (resolution \(1\ \mathrm{km} \times 1\ \mathrm{km}\) or \(2\ \mathrm{km} \times 2\ \mathrm{km}\))
    • administrative boundaries
    • general land cover, cities, etc.
  • Continuous spatialized climate data:
    • monthly global radiation from the Helioclim-1 database (École des Mines de Paris / Armines)
    • data based on Meteosat images (1985–2004) and the HelioSat-2 method, with a resolution of approximately \(30 \times 30\ \mathrm{km²}\)
    • air temperature