Which transparency does this customer need?

Latitude sets how high the sun climbs and how long the day lasts, month by month. That is what fixes how much light physically arrives before any weather is considered. Imathia, Greece is the default. Longitude is carried for reference only.

The share of possible sunlight that actually gets through the atmosphere over a year, after clouds and haze. Roughly 0.40 in maritime northern Europe, 0.55 to 0.62 around the Mediterranean. It scales every light figure on the page, and it also sets how much of the light is diffuse — a cloudy sky sends light from everywhere, which slips past the panels more easily than direct sun does.

A tent puts the ridge in the middle of the band, so the shadow stays roughly in place as the sun moves and the light on the crop is noticeably more even. A shed casts a shadow that sweeps sideways through the day: some strips of ground get a lot of sun and others very little, which shows up later as uneven ripening and uneven fruit size. A shed usually produces a little more electricity if it faces the sun; a tent trades some of that for a flatter output curve across the day, which suits a farm that uses its own power.

With rows running north to south, the shadow sweeps from one side to the other during the day, so every plant gets direct sun at some point. With rows running east to west, the shadow barely moves, and a strip of ground can sit in shade all day while another strip never does. Same amount of light in total, very different evenness — and evenness is what determines whether a whole block ripens together.

Distance from the centre of one row to the next. Together with the band width it sets how much of the sky is covered. This is usually fixed by the existing plantation, not by the solar design.

How wide the panel band above each row is, measured along the slope. Wider band means more power and more shade. This is the main thing the solar designer can actually choose.

Height from the crop canopy to the lowest point of the panels. Higher mounting blurs the shadow edges and spreads the light more evenly, but costs more steel and more wind load. It changes evenness considerably and total light only slightly.

Angle of the panels from horizontal. Steeper tilt catches more sun in winter and less in summer, and changes how wide the shadow is when the sun is low. On a tent, both slopes carry this angle in opposite directions.

How much light passes through the coated glass in the gaps between cells. Not the same as module transparency, which also counts the cells. Brite can measure this exactly with a spectrophotometer — it is one of the few numbers here that only the manufacturer can supply.

How much light bounces back up off the ground. A green canopy reflects about 0.20 to 0.25, dry soil about 0.15, grass in between. For double-sided panels this reflected light is what the rear side collects, so a crop underneath quietly changes the electricity yield.

Ratio of measured to modelled light reduction. Real orchards lose less light than a simple geometric model predicts, because the canopy scatters light sideways and light arrives around the edges of the band. This is set so the model reproduces the one published orchard measurement available — 23.8% reduction at the Bierbeek pear trial in Belgium. One season of sensor data from a real installation would replace this with a measured value, and that is the single most valuable piece of data missing.