Technical specifications

SOLETAIR process aims for 100% renewable solution, which combines CO2 from air and electricity from sun into sustainable consumer products. Our demonstration facility includes a solar field and three mobile container units: electrolyzer for hydrogen production, direct air capture for CO2 production and intensified synthesis reactors for hydrocarbon production. Our ambition is to integrate these units successfully and demonstrate that 100% renewable future is possible

Phase 1: Renewable energy

Phase 2: Hydrogen production

Proton exchange membrane (PEM) water electrolysis process is used in hydrogen production. The system produces high-purity hydrogen gas at elevated pressures. Hydrogen is used with recycled carbon dioxide to produce renewable fuels, raw materials, and chemicals in MOBSU. The hydrogen gas can also be used as a chemical energy storage and can later be reconverted into electricity in a fuel cell, albeit with an additional penalty in terms of losses in conversion.

A hydrogen production system is built in a standard shipping container and virtually connected to a renewable energy source, the 206.5 kWp solar PV power plant at LUT. In other words, the water electrolysis process can be selected to be operated according the instantaneous solar PV production or according to recorded solar PV production figures.

Water electrolysis process is used in hydrogen production.

The process in the hydrogen production system is the following: Water can be stored in a 1 m3 buffer tank and then supplied to a reverse-osmosis unit. The purified water is further deionized in order to decrease the conductivity of the water in order to preserve the lifetime of the electrolysis unit. The 5 kW proton exchange membrane electrolyser splits the water molecules into hydrogen and oxygen gas, when DC current is supplied to the electrodes. Hydrogen is formed at the cathode and oxygen at the anode side of the electrolyser.

Due to the compact design of the proton exchange membrane electrolyser, the cathode compartment pressure can be adjusted to a much higher pressure compared to the anode compartment pressure. The PEM electrolyser at LUT can produce hydrogen at a maximum outlet pressure of 50 bar, while the oxygen outlet pressure is kept at 2 bar. Operating temperature of the electrolysis unit is controlled to 70 °C by water cooling. The hydrogen production unit is produced by a Danish company EWII, but modified to enable the adjustment of both gas outlet pressures by back-pressure valves.

The hydrogen gas produced by the proton exchange membrane electrolyser is processed in a hydrogen gas drying unit to decrease the dewpoint down to −70 °C. Minimizing the water content in the hydrogen gas outlet prevents the gas from freezing in Nordic winter conditions, when the gas is supplied to outdoor gas storage. The produced dry hydrogen gas is stored into two 350 l composite cylinders. From the gas storage, the hydrogen can be supplied to the MOBSU synthesis unit or a PEM fuel cell located in the hydrogen production container.

Phase 3: Direct Air Capture (DAC)

Phase 4: Mobile Synthesis Unit (MOBSU)

Phase 5: Refinining of renewable products

Phase 6: Renewable consumer products

Specific calculations

  • FT Products


  • Energy Consumption


  • CO2 Input


  • Water Consumption



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