vocabulary: name: Solcast Solar Energy Vocabulary description: >- Domain vocabulary for the Solcast API covering solar irradiance, PV power, meteorological parameters, soiling models, grid aggregation, and resource assessment. Aligned with IEC, ISO, and PVGIS conventions. version: "1.0.0" created: "2026-05-02" modified: "2026-05-02" source: https://docs.solcast.com.au/ terms: # ─── Core Solar Irradiance Terms ───────────────────────────────────────── - term: GHI label: Global Horizontal Irradiance abbreviation: GHI unit: "W/m²" description: >- The total solar radiation received on a horizontal surface, including both direct beam radiation and scattered diffuse radiation. The primary metric for evaluating solar resource potential at a location. category: Irradiance related: - DNI - DHI - EBH - term: DNI label: Direct Normal Irradiance abbreviation: DNI unit: "W/m²" description: >- Solar radiation measured on a surface perpendicular (normal) to the direct beam from the sun. Critical for concentrating solar power (CSP) systems. category: Irradiance related: - GHI - DHI - term: DHI label: Diffuse Horizontal Irradiance abbreviation: DHI unit: "W/m²" description: >- The scattered component of solar radiation arriving at a horizontal surface from all parts of the sky dome excluding the direct beam. Significant on cloudy days and for bifacial PV systems. category: Irradiance related: - GHI - DNI - term: EBH label: Beam Horizontal Irradiance abbreviation: EBH unit: "W/m²" description: >- The direct beam component of solar radiation received on a horizontal surface. Equivalent to DNI multiplied by the cosine of the solar zenith angle. category: Irradiance related: - GHI - DNI - term: clearsky_ghi label: Clear-Sky GHI unit: "W/m²" description: >- The GHI that would be measured under a completely clear (cloud-free) atmosphere. Used as a reference to compute the clear-sky index and diagnose cloud impacts. category: Irradiance related: - GHI - cloud_opacity - term: cloud_opacity label: Cloud Opacity unit: "percent (0–100)" description: >- Solcast's proprietary measure of effective cloud cover derived from satellite imagery. 0 = completely clear sky, 100 = fully overcast. Used internally to compute irradiance attenuation. category: Meteorology related: - GHI - clearsky_ghi # ─── PV Power Terms ─────────────────────────────────────────────────────── - term: pv_estimate label: PV Estimate (Capacity Fraction) unit: "dimensionless (0–1)" description: >- The estimated PV power output expressed as a fraction of the system's rated DC capacity. A value of 1.0 means full-rated output. The central (P50) probabilistic estimate. category: PV Power related: - pv_estimate10 - pv_estimate90 - pv_power_rooftop - term: pv_estimate10 label: PV Estimate P10 unit: "dimensionless (0–1)" description: >- 10th-percentile PV power estimate. A pessimistic bound: actual output is expected to exceed this value 90% of the time. Used for conservative energy production forecasts in project financing. category: PV Power related: - pv_estimate - pv_estimate90 - term: pv_estimate90 label: PV Estimate P90 unit: "dimensionless (0–1)" description: >- 90th-percentile PV power estimate. An optimistic bound: actual output is expected to be at or below this value 90% of the time. category: PV Power related: - pv_estimate - pv_estimate10 - term: pv_power_rooftop label: Rooftop PV Power unit: "kW" description: >- Estimated PV power output in kilowatts for a rooftop installation, computed using Solcast's basic PV model with latitude/longitude inputs. Does not require site registration. category: PV Power related: - pv_estimate - pv_power_advanced - term: pv_power_advanced label: Advanced PV Power unit: "kW" description: >- High-specification PV power output in kilowatts computed using Solcast's advanced PV model for a registered site (resource_id required). Incorporates full system specifications including tilt, azimuth, capacity, tracking type, and loss factor. category: PV Power related: - pv_power_rooftop - resource_id # ─── Meteorological Terms ───────────────────────────────────────────────── - term: air_temp label: Air Temperature unit: "°C" description: >- Air temperature at 2 metres above ground level in degrees Celsius. Affects PV panel efficiency (output decreases at high temperatures) and is used in PV performance modelling. category: Meteorology - term: wind_speed_10m label: Wind Speed at 10m unit: "m/s" description: >- Horizontal wind speed at 10 metres height. Used for PV panel cooling calculations, wind turbine power curves, and structural load assessments. category: Meteorology - term: wind_direction_10m label: Wind Direction at 10m unit: "degrees (0–360, clockwise from north)" description: >- Direction from which the wind is blowing at 10m height, in degrees clockwise from north (0/360 = north, 90 = east, 180 = south, 270 = west). category: Meteorology - term: relative_humidity label: Relative Humidity unit: "percent (0–100)" description: >- Relative humidity at 2 metres height as a percentage. Used in soiling models and atmospheric correction calculations. category: Meteorology - term: surface_pressure label: Surface Pressure unit: "hPa" description: >- Atmospheric pressure at the surface in hectopascals. Used in air mass calculations and atmospheric correction of irradiance. category: Meteorology - term: precipitable_water label: Precipitable Water unit: "kg/m²" description: >- Total amount of water vapour in the atmosphere above a given location, expressed as the equivalent depth of liquid water. Affects infrared radiation absorption and DNI. category: Meteorology # ─── Solar Geometry Terms ───────────────────────────────────────────────── - term: solar_zenith label: Solar Zenith Angle unit: "degrees (0–90)" description: >- Angle between the sun and the vertical (zenith). 0° = sun directly overhead, 90° = sun at the horizon. Controls the air mass and irradiance intensity at the surface. category: Solar Geometry - term: solar_azimuth label: Solar Azimuth Angle unit: "degrees (0–360)" description: >- Horizontal angle of the sun measured clockwise from north. 180° = due south (northern hemisphere mid-day peak). category: Solar Geometry - term: solar_elevation label: Solar Elevation Angle unit: "degrees (-90 to 90)" description: >- Angle of the sun above the horizon. Complement of the zenith angle. Negative at night. category: Solar Geometry # ─── Soiling Terms ──────────────────────────────────────────────────────── - term: soiling_loss label: Soiling Loss unit: "fraction (0–1)" description: >- Cumulative soiling loss factor representing the fraction of output lost due to accumulated dust, pollen, bird droppings, or other contaminants on the panel surface. 0 = clean, 1 = fully soiled. category: Soiling related: - cleanliness - kimber_model - hsu_model - term: cleanliness label: Panel Cleanliness unit: "fraction (0–1)" description: >- Complement of soiling loss. 1.0 = perfectly clean panel. Derived from the soiling model as (1 - soiling_loss). category: Soiling related: - soiling_loss - term: kimber_model label: Kimber Soiling Model description: >- A physically-based PV soiling model implemented in pvlib that estimates panel soiling as a function of time since last rain event, dust deposition velocity, and local meteorology. Supported for live, forecast, and historic data via Solcast. category: Soiling related: - soiling_loss - hsu_model - term: hsu_model label: HSU Soiling Model description: >- Solcast's internally developed soiling model (HSU) that uses satellite- derived atmospheric dust loading (aerosol optical depth), precipitation, and local meteorology to estimate cumulative panel soiling. category: Soiling related: - soiling_loss - kimber_model - term: depo_veloc_pm10 label: PM10 Deposition Velocity unit: "m/s" description: >- Gravitational settling velocity of PM10 particulate matter (diameter ≤10 µm). Input parameter for the Kimber and HSU soiling models. Controls how fast dust deposits on panel surfaces. category: Soiling - term: snow_soiling_rooftop label: Snow Soiling Loss Factor unit: "fraction (0–1)" description: >- Estimated fractional PV output loss due to snow accumulation on rooftop panel surfaces. Derived from snow depth, temperature, and panel tilt. category: Soiling related: - snow_depth # ─── Time-Series Terms ──────────────────────────────────────────────────── - term: period_end label: Period End Time description: >- The timestamp marking the end of a data interval in UTC (ISO 8601). Solcast uses period-end conventions — data in a 30-minute period ending at 06:30 UTC covers 06:00–06:30 UTC. category: Time Series - term: period label: Time Period Duration description: >- ISO 8601 duration string specifying the length of each data interval (e.g., PT5M = 5 minutes, PT30M = 30 minutes, PT60M = 60 minutes). Solcast supports 5, 10, 15, 30, and 60-minute periods depending on the endpoint and subscription. category: Time Series - term: TMY label: Typical Meteorological Year abbreviation: TMY description: >- A statistically derived annual dataset representing the long-run average solar and weather conditions at a location. Solcast TMY is calculated from 2007 to 2023 satellite data. Used for solar project feasibility and bankable energy yield assessments. category: Resource Assessment related: - P50 - historical_data - term: P50 label: P50 Energy Yield description: >- The median expected annual energy yield from a PV system — the value exceeded in 50% of years. Standard reference for project valuation. category: Resource Assessment related: - P90 - TMY - term: P90 label: P90 Energy Yield description: >- The energy yield exceeded in 90% of years. Pessimistic benchmark used by debt financiers and lenders for solar project risk assessment. category: Resource Assessment related: - P50 # ─── Site Management Terms ──────────────────────────────────────────────── - term: resource_id label: Resource ID description: >- A unique alphanumeric identifier (UUID-like format, e.g., ba75-e17a-7374-95ed) assigned by Solcast to a registered PV power site. Used as the primary key for all advanced PV power data queries. category: Site Management - term: tracking_type label: Panel Tracking Type description: >- The mechanical mounting system of PV panels. Values: fixed (no movement), horizontal_single_axis (rotates east–west on a north–south horizontal axis), vertical_single_axis (rotates around a vertical axis), two_axis (tracks both azimuth and elevation for maximum irradiance capture). category: Site Management values: - fixed - horizontal_single_axis - vertical_single_axis - two_axis - term: loss_factor label: System Loss Factor unit: "fraction (0–1)" description: >- A single aggregate de-rating coefficient accounting for all system losses including wiring resistance, inverter inefficiency, module mismatch, soiling, shading, and degradation. Applied uniformly to the modelled PV output. Typical values range from 0.75 to 0.95. category: Site Management # ─── Grid Aggregation Terms ─────────────────────────────────────────────── - term: collection_id label: Collection ID description: >- Unique identifier for a Solcast grid aggregation collection — a group of PV sites or regions aggregated for grid management purposes (e.g., a distribution network service area or a portfolio of utility-scale farms). category: Grid Aggregation - term: aggregation_id label: Aggregation ID description: >- Unique identifier for a sub-aggregation within a collection. Allows hierarchical aggregation (e.g., regional zones within a national grid). category: Grid Aggregation categories: - name: Irradiance description: Solar radiation parameters measured in W/m². - name: PV Power description: Photovoltaic power output estimates in kW or as capacity fractions. - name: Meteorology description: Atmospheric and weather parameters influencing solar resource. - name: Solar Geometry description: Sun position angles used in irradiance and PV calculations. - name: Soiling description: Panel soiling loss models and parameters. - name: Time Series description: Temporal metadata for all data points. - name: Resource Assessment description: Long-run average and probabilistic yield analysis terms. - name: Site Management description: PV power site registration and specification terms. - name: Grid Aggregation description: Fleet and portfolio aggregation identifiers and concepts.