Voltiris for Dava
Technology session · Thursday 5 November 2026 · 12:00 Riyadh

The greenhouse roof as the power plant, without shading the crop

Spectral-filtering solar modules let through the light plants use and turn the rest into electricity and a cooler crop. Prepared for Dava Agricultural.

Nicolas WeberCo-Founder & CEO
Jonas RochCo-Founder & CTO
Voltiris SALausanne, Switzerland · The Hague
Sunlight by wavelength (AM1.5G, 400 to 1200 nm). Drag across the spectrum.Hover or touch to read
~45%
of sunlight is what plants use (PAR, 400 to 700 nm). It passes through the filter to the crop.
~55%
is near-infrared and beyond. The filter reflects it onto solar cells: electricity, not heat in the greenhouse.
3M
co-developed spectral film. 5 patents, 3 owned and 2 filed jointly with 3M.
Dava · context

Dava is scaling from 85 to 350 ha of high-tech greenhouses, in a climate where the sun is both the cost and the resource

Today
85 ha

glass hydroponic greenhouses, 135 t/day, 13.8% of Saudi greenhouse output

2027
+23 ha

polycarbonate, Al-Kharj

2028
+20 ha

semi-closed glass, Al-Kharj · 250 t/day

2030
350 ha

high-tech greenhouses, 1,000 t/day, Taif mega-project with a 65 ha solar park

Sources: HortiDaily (May 2026), Debets Schalke press release, dava.sa.

What the sun costs a Saudi greenhouse

Heat

Dava's greenhouses run on heavy air conditioning. Every watt of near-infrared that comes through the roof is a watt the AC has to pull back out, at the hour of the day when electricity is dearest.

Electricity

Ground solar takes land that could grow crops, and still needs cabling back to the greenhouse.

Light

Conventional PV on the roof shades the crop. On tomato and cucumber, 1% less light is 1% less yield.

Voltiris turns the roof into the power plant: the near-infrared leaves the greenhouse as electricity instead of heat, and the crop keeps all its light.

Four ways Voltiris cools the crop
heat → PVblue + redgridairleaf123
  1. 1

    Only blue and red go through

    The modules filter the sunlight high up, at truss level. The blue and red light the plants use passes to the crop. The near-infrared, and most of the heat with it, is concentrated onto the solar cells.

  2. 2

    Cooler leaves

    With less near-infrared reaching the crop, air temperature stays about the same but the leaves run cooler: 3 to 6 °C lower on sunny days. The plant responds mainly to its leaf temperature.

  3. 3

    Heat leaves as electricity

    The cells turn that heat into electricity. Instead of warming the greenhouse air, it leaves through the cable to the grid.

6:009:0012:0015:0018:00Voltiris powercooling need

Schematic sunny day

4

Power when it matters most

Output peaks at noon on hot, sunny days, exactly when the greenhouse needs the most cooling. Connected to the AC, each kWh works twice: it is heat that never reached the crop, and it runs the AC to cool the greenhouse further.

How it works

Plants use only 45% of sunlight. Voltiris lets that part through and turns the remaining 55% into electricity

Voltiris module: spectral filter on a two-axis tracker with solar cells
What it does for the crop

Under Voltiris, tomatoes spend 74% of the time in their optimal range, against 57% in the control compartment

Share of time at each leaf temperature, 2025 season
Control compartmentWith VoltirisOptimal 20 to 25 °CAbove 28 °C, pollination falters
Time in optimal range
74%vs 57%
20 to 25 °C, where tomato grows and sets fruit best
Time above 28 °C
~1%vs 11%
Pollination declines above 28 °C
Leaf temperature on sunny days
−3to −6 °C
No effect on cloudy days: the crop keeps the warmth it needs
Summer whitewash
0
In warm weeks the modules replace whitewash and produce as much as the control

Leaf temperature measured in a European glasshouse. In Al-Kharj the gap is expected to be larger; we will measure it with you.

Agro results by crop

Across tomato, cucumber, pepper, lettuce and strawberry, yields held or rose under the modules

Meier Gemüse (CH) · cherry tomato · 2025 · two compartments of ~4,000 m²
+1.5%

cumulative yield under Voltiris versus the control compartment, each against its own 2024 harvest

Control compartment−1%2025 vs 2024
Voltiris compartment+1%2025 vs 2024

First full season under 1,736 modules, grower data. Climate settings were not yet adapted to the cooler crop.

Les Cleons (FR) · cucumber · sunny heatwave day, 2026 · light at crop level
Radiation at crop level over the day at Les Cleons: under Voltiris the screens stay open longer in the morning and afternoon, giving 30% more light than the control
VoltirisControl

The control closed its screens against the heat. Under the modules they stayed open longer, for 30% more light over the day.

Tomato

Yield stable at hectare scale, plant 5 to 6 °C cooler

Meier Gemüse (CH, 4.5 ha): 2025 yield in line with 2023 and 2024. Les Cleons (FR): plant temperature up to 5 to 6 °C lower on sunny days; the grower: "exactly what we were hoping for".

Cucumber

+30% light in a heatwave: screens stay open longer

Les Cleons (FR, 2026): on a sunny heatwave day the screens stayed open longer under the modules, for 30% more light than the control. In Saudi greenhouses that shade heavily against heat, this means less shading for the same or lower temperature, and more light for the crop.

Bell pepper

+9% harvest late in the season

Delphy Light Improvement Center (NL, 2024): leaves up to 5 °C cooler on a sunny day. The crop suffered less from heat and harvested 9% more towards the end of the season. Agroscope (CH): +5% total yield in a comparative study.

Lettuce

+12% head weight in Gulf heat

Gheras (Bahrain), 42 weeks hydroponic in a pad-and-fan polyhouse: +12% average weight, 30% more consistent yield, +7% leaf area, filter only.

Strawberry

+5% total yield, +9.5% fruits per plant

Estidamah (Saudi Arabia), low-tech greenhouses: +6.3% marketable yield, ~6% higher water use efficiency. Genson (NL): 2026 hectare-scale installation on strawberries.

Voltiris in the Gulf

The filter alone already improved yields in Saudi Arabia and Bahrain

Both trials used the spectral film only, without the modules. The full system adds tracking, concentration and electricity on top.

Spectral filter trial in Saudi Arabia
Estidamah · Saudi Arabia
Spectral filter trial in Bahrain
Gheras · Bahrain
Spectral filter trial in Bahrain
Gheras · Bahrain
Estidamah · strawberries
+5%
Total yield in low-tech greenhouses
  • +6.3% marketable yield
  • +9.5% fruits per plant
  • ~6% higher water use efficiency
Gheras · hydroponic lettuce
+12%
Average head weight, 42-week trial, pad-and-fan polyhouse
  • 30% more consistent yield
  • +7% leaf area
  • ~3.5 °C lower temperature under the filter
Track record

Four hectare-scale installations in two seasons, on the crops Dava grows

20+ installations across Europe, Asia and North America. Every project so far has shown neutral or positive crop impact.

Voltiris modules above a tomato greenhouse
Switzerland · 2025

Meier Gemüse

Tomato

First hectare-scale project. 1,736 modules, 236 kWp, installed in 4 weeks with greenhouse builder Horconex.

Voltiris modules inside a glasshouse
Netherlands · 2026

Genson

Strawberry

Hectare-scale installation in Someren, supplying Albert Heijn through Bakker Barendrecht.

Geneva, Switzerland · 2026

Blondin

Tomato

1 ha, 400 kWp on a tomato greenhouse, installed during the 2026 heat waves.

Geneva, Switzerland · 2026

Magnin

Cucumber

1 ha, 400 kWp on a cucumber greenhouse, 2026 season.

Your site

What one of your greenhouse blocks would carry

Indicative, at the maximum density of 2,500 modules of 145 Wp per hectare (362.5 kWp/ha). A site study with your greenhouse drawings replaces these numbers; annual energy is modelled per site from Al-Kharj irradiance.

Modules, maximum
50,000
145 Wp each, up to 2,500 per hectare, hung in the greenhouse structure
Installed capacity, maximum
7.3MWp
behind the meter, no land used
Land saved vs ground solar
~5.1ha
assuming 0.7 ha per MWp for ground-mounted PV
Cooling
2×
Each kWh of near-infrared turned into electricity is a kWh of heat that never entered the greenhouse, so the AC does not have to remove it. The same light pays twice: as power produced and as cooling avoided.
A first project with Dava

One compartment measured against a control, then designed into the next glass build

01 · Validate

One compartment, one season

A 1 ha glass compartment, tomato or cucumber, with a matching control compartment. Plant temperature, yield, water and electricity tracked weekly, with a local institute if Dava wishes.

2027 season
02 · Deploy

First commercial block

Designed in with Debets Schalke on the 20 ha semi-closed glass build or the Taif polycarbonate blocks, where modules replace whitewash and part of the cooling load.

2028 build
03 · Scale

Across the 350 ha roadmap

Behind-the-meter electricity on every glass block, alongside the Taif solar park. Direct sale or Energy as a Service, with no capex for Dava.

2028 onward

To settle together today

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