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Subscription ManagementAccount FAQsParameter Definitions
This page provides detailed explanation on the parameters that are available within the Solcast API.
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Name | Definition | How we use this | Unit | Valid range | Defaults |
Name | The user-defined name of the site. | Used to display a name for your site. Can be changed. | N/A | None, required | |
Latitude | Site latitude (centre of site) in decimal degrees (EPSG:4326). | Used to locate your site. | ° | -90 to +90 | None - Required field |
Longitude | Site longitude (centre of site) in decimal degrees (EPSG:4326). | Used to locate your site. | ° | -180 to +180 | None - Required field |
Tracking type | The type of sun-tracking or geometrical configuration of your site's modules | Used to calculate the incident irradiance for your modules | N/A | "fixed_tilt" or "horizontal_single_axis" | None - Required field |
Install date | The date when your site was installed | Used to derate your module (DC) production gradually with age, at a rate dependent on your Module Type | date | 1970-01-01 to present date | 1 year before date at site creation |
AC capacity (inverters) | Total inverter (nameplate) capacity in MW. This is the highest potential output of the system before any Site Export Limit is applied | Used to model the conversion of DC power to AC by your inverters | MW | >=0 | None – Required field |
DC capacity (modules) | Total module capacity in MW. Usually slightly higher than the AC capacity. | Used to model the generation of DC power by your modules | MW | >=0 | 1.27*AC capacity |
Grid export limit | The maximum power export limit in MW that is allowed by the site's connection with the network operator | Used to place a final cap on your AC power output. Only impacts your AC power if the grid export limit is set lower than the AC capacity | MW | >=0 | Disabled |
Name | Definition | How we use this | Unit | Valid range | Defaults |
Other losses derating coefficient | The factor by which the whole system will be derated due to causes other than temperature and degradation. | Used to calculate other system losses including mismatch, wiring and connection. | fraction | 0 to 1 | Inferred from AC capacity if not specified |
Age degradation derating coefficient | The factor by which the whole system will be derated per year since the Install Date. | Used to calculate time dependent system loss. | year-1 | 0 to 1 | 0.0023 (mono-Si) 0.0059 (poly-Si) 0.0095 (a-Si) 0.0030 (CdTe) 0.0002 (CIGS) |
Peak inverter efficiency | The peak efficiency value in your inverter efficiency curve. | Used to scale the conversion efficiency of DC to AC, as a function of the inverter load. | fraction | 0 to 1 | 0.985 |
Module temperature derating coefficient | The factor by which your site's module (DC) production will be derated with increasing temperature. | Used to derate your module (DC) production gradually with increasing temperature. | K-1 | -1 to 0 | 0.0039 (mono-Si) 0.0039 (poly-Si) 0.0031 (a-Si) 0.0026 (CdTe) 0.0042 (CIGS) |
Ground coverage ratio | The proportion of the site's ground area covered by modules. | Used to calculate the incident irradiance for your modules. | fraction | 0 to 1 | 0.36 if tracking_type is horizontal_single_axis 0.47 if tracking type is fixed |
Module type | The type of material or technology used in your site's PV modules. | Used to estimate your module temperature derating coefficient (unless you specify your own coefficient) and used to estimate your module age derating. | N/A | Monocrystalline Silicon (mono-Si) Polycrystalline Silicon (poly-Si) Amorphous Silicon (a-Si) Cadmium Telluride (CdTe) Copper Indium Gallium Selenide (CIGS) | Polycrystalline Silicon (poly-Si) if install date is >= 2013 Monocrystalline Silicon (mono-Si) if install date < 2013 |
Name | Definition | How we use this | Unit | Valid range | Defaults |
Module azimuth angle | The off-north-facing direction on the horizon in which the modules are facing for a fixed-tilt site. | Used to calculate the incident irradiance for your modules. | ° | -180 to 180. South is -180, East is -90, North is 0, West is 90 | Set to 0 if latitude is less than zero, otherwise set to 180 |
Module tilt angle | The off-horizontal tilt angle of modules for a fixed-tilt site. | Used to calculate the incident irradiance for your modules. | ° | 0 to 90. Zero means the modules are horizontal | Quadratic function of site Latitude |
Name | Definition | How we use this | Unit | Valid range | Defaults |
Tracker smart tracking | Whether the trackers move to horizontal during cloudy periods with zero DNI, for a horizontal single axis tracking site. | Used to calculate the incident irradiance for your modules. | boolean | True, False | False |
Tracker back-tracking | Whether the trackers backtrack at low solar elevation angles, for a horizontal single axis tracking site. | Used to calculate the incident irradiance for your modules. | boolean | True, False | True if install date is >Jan 2015, else False |
Tracker maximum rotation angle | The maximum off-horizontal angle for a horizontal single axis tracking site. | Used to calculate the incident irradiance for your modules. | ° | 0 to 90 | 50 ° |
Tracker axis azimuth angle | The off north-south azimuth angle for a horizontal single axis tracking site. Most commonly this will be close to zero. | Used to calculate the incident irradiance for your modules. | ° | -180 to 180. South is -180, East is -90, North is 0, West is 90 | 0 (north-south axis) |
Name | Definition | How we use this | Unit | Valid range | Defaults |
Topographic horizon elevation | The elevation angle of topography (e.g. hills and mountains) surrounding the general area of your site, at a set of specified different azimuth (direction) angles. | Used to calculate the incident irradiance for your modules | ° | 0 to 90 for each elevation value. -180 to 180 for each azimuth value. The list must have the same number of azimuths and elevations | 0° elevation at every azimuth |
Average dust soiling losses | The average proportion of module production lost due to dust soiling, from 0 to 1. E.g. 0.02 for April means a 2% soiling loss will be applied throughout April. The value entered should reflect the impact of cleaning activity at your site. | Used to calculate the module (DC) production We accept either a single yearly average value, or a set of 12 monthly average values. | fraction | 0 to 1 | 0.015 |
Average terrain azimuth | The average terrain slope downhill direction. | Used to calculate the incident irradiance for your modules. Terrain Azimuth is meaningful only when terrain_slope>0. | ° | -180 to 180. South is -180, East is -90, North is 0, West is 90. | 0° |
Average terrain slope | The average terrain slope in degrees of your site. A site with no terrain slope has a value of zero. | Used to calculate the incident irradiance for your modules. | ° | 0 to 90 | 0° |
"apply" plant condition parameters
These optional parameters exist to accommodate deviations in the actual operating condition of the plant, which can vary from minute-to-minute or day-to-day and therefore are not suitable to be semi-permanent plant specification metadata like the parameters above. When these parameters are not used, the above plant specification metadata is used. The "apply" parameters can be optionally specified in the API request, with no delay in receiving forecasts back from the Solcast API. Not all "apply" parameters need to be provided in the request, only the parameters relating to the actual changes in plant operating conditions.
Name | Definition | How we use this | Unit | Valid range | Defaults |
apply_tracker_inactive | Indicating if trackers are inactive. If True, panels are assumed all facing up (i.e. zero rotation). Only has effect if your site has a tracking_type that is not "fixed". | Used to calculate the module (DC) production | Boolean | True-False | False |
apply_snow_soiling | A user-override for Solcast's dynamic snow soiling, which is based on global snow cover and weather forecast data, and changes from hour-to-hour. If you specify this parameter in your API call (e.g. if snow clearing has just been performed), we will replace the Solcast dynamic hour-to-hour value with the single value that you specify. E.g. if you specify a 0.7 snow soiling, your returned power will be reduced by 70%. | Used to calculate the module (DC) production. | boolean | True-False | False |
apply_dust_soiling | A user-override for dust_soiling_average. If you specify this parameter in your API call, we will replace the annual or monthly average dust soiling values for the site with the value you specify in your API call. E.g. if you specify a 0.7 dust soiling, your returned power will be reduced by 70%. | Used to calculate the module (DC) production. | boolean | True-False | False |
apply_constraint | Constraint on site's total AC production, applied as a cap in the same way as the metadata parameter Site Export Limit. This will constrain all Solcast power values to be no higher than the apply_constraint value you specify. If you need an unconstrained forecast, you should not use this parameter. | To adjust the pv power value returned by the Solcast API. | boolean | True-False | False |
apply_availability | Proportion of the site's total AC (inverter) capacity that is currently generating or expected to be generating during the forecast request period. E.g. if you specify a 30% availability, your returned power will be a maximum of 30% of AC capacity. | To adjust the pv power value returned by the Solcast API. | boolean | True-False | False |