AgRadiance Glossary
Agrivoltaics glossary
The terms you meet in agrivoltaic studies, permits and our reports, explained briefly.
- Agrivoltaics
- The combined use of land for solar power and agriculture, designed so that both remain productive. Also called agri-PV, agrophotovoltaics or solar sharing.
- APV category I (elevated)
- Agrivoltaic systems with a clear height above 2.1 m, so farming continues under the modules, including with large machinery. Defined in DIN SPEC 91434.
- APV category II (interspace)
- Ground-mounted systems where farming takes place between and around the module rows. Defined in DIN SPEC 91434.
- Vertical bifacial systems
- Vertical rows of bifacial modules, usually facing east and west, with farming on both sides. In DIN SPEC 91434 they fall under category II.
- DIN SPEC 91434
- The German specification for agrivoltaic systems. It defines the categories, requires the agricultural yield to stay at least 66 % of a reference, and sets the land-use and documentation rules. A key reference for German permits.
- Ground coverage ratio (GCR)
- Module area divided by the ground area it covers. A lower GCR leaves more light for the crop; a higher GCR gives more energy per hectare.
- Pitch
- The distance from one module row to the next, measured axis to axis. Together with the axis height it sets how much light and space the crop gets.
- Daily light integral (DLI)
- The photosynthetically active light a crop receives over a day, in mol/m² per day. A key indicator of growth potential under shade.
- Photosynthetically active radiation (PAR)
- The part of sunlight, 400–700 nm, that plants use for photosynthesis.
- Evapotranspiration
- Water leaving the field by evaporation from the soil and transpiration from the plants. Shade from the modules usually lowers it, which reduces irrigation demand.
- Microclimate
- The local temperature, humidity and wind the crop experiences. Under an array it differs between the zone under the modules, between the rows and at the edges.
- Shading
- The share of light the modules take from the crop compared with the open field. It changes with position, time of day, season and the geometry of the array.
- Bifacial module
- A module that also generates power from light reaching its back, mostly light reflected by the ground.
- Single-axis tracker
- A mounting system that turns the modules around one axis, usually north–south, to follow the sun. The shade moves across the crop through the day.
- Albedo
- The share of sunlight a surface reflects, from 0 to 1. It affects both the rear-side yield of bifacial modules and the light under the array.
- Leaf area index (LAI)
- Leaf area per unit of ground area, in m²/m². An indicator of canopy density and of how much light the crop can intercept.
- Ray tracing
- Tracing light from the sun through a 3D model of the array onto the crop, to calculate how much direct, diffuse and reflected light each point receives.
- Land equivalent ratio (LER)
- How much land separate solar and farming would need to match one hectare of agrivoltaics. An LER above 1 means the shared use is more productive than separate use.
- P10–P90 range
- The range a result falls in across weather years: in 10 % of years it is below P10, in 10 % above P90. We report ranges because one average hides the dry and hot years.
- Headland
- The strip at the end of the rows where machinery turns. Its depth depends on the machine and the turn it can make.
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