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Data / Historical Solar Capacity Factors

Hourly solar PV capacity factors derived from ECMWF ERA5 reanalysis: global, 1940 to present, at hourly resolution, refreshed every three months.

License: CC BY 4.0
Open in Convexity

Overview

Hourly solar PV capacity factors for anywhere on Earth, derived from ECMWF ERA5 reanalysis. The series runs from 1940 to the present at hourly resolution on ERA5's native ~31 km grid, and is refreshed every three months as the reanalysis extends toward real time. The result is a long, internally consistent baseline for capacity-expansion, dispatch and resource-assessment work: one weather record, one method, eight decades deep.

Illustrative surface solar irradiance over a representative period. Source: ERA5 reanalysis (ECMWF).

What's included

  • Hourly capacity factors (0 to 1) for fixed-tilt solar PV, for any location worldwide
  • The full ERA5 record, 1940 to present, as a single continuous, gap-free series
  • Latitude-optimised tilt at every location, so the factors reflect a sensibly sited array rather than a flat panel
  • Temperature-aware output that captures the efficiency a panel loses on hot days, not just the available sunlight

How it's built

Starting from ERA5's hourly surface irradiance and 2 m temperature, we reconstruct the sun's position at each location and hour and split the incoming light into its direct and diffuse components. That irradiance is transposed onto the plane of a tilted panel, with tilt optimised to local latitude, and combined with ground reflection to give the energy actually striking the array. Plane-of-array irradiance and ambient temperature are then run through a PV performance model and inverter losses to yield an hourly capacity factor. The output is a physically grounded estimate of what a well-sited fixed-tilt array would have produced, hour by hour, going back to 1940.

Availability

Explore and download these capacity factors through Convexity, Bayesian Energy's energy-system modelling application, free to use in the browser. An open API for programmatic access is coming soon.

Source and attribution

Derived by Bayesian Energy from ERA5 reanalysis, produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) for the Copernicus Climate Change Service (C3S). Contains modified Copernicus Climate Change Service information. Neither the European Commission nor ECMWF is responsible for any use of the Copernicus information on which this derived product is based.

The capacity-factor dataset is released by Bayesian Energy under CC BY 4.0, free to use, including commercially, with attribution.