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Capturing CO2 from the air and binding it in underground basalt

Hellisheidi geothermal power plant. Photo: Arni Saeberg / Climeworks

In Iceland a project has been started to test the process on an industrial scale

A new technology to capture CO2 directly from the air and tp bind it in underground basalt layers comes from Switzerland. Swiss Climeworks company together with Icelandic Reykjavik Energy has recently started a project where the process shall be tested on an industrial scale.

The plant is located in Hellisheidi about 30 km southeast of Iceland’s capital Reykjavik.

The idea is patented and based on an old chemical reaction in nature: it is that water may absorb CO2 from the air. The result is a weak acid which may release this CO2 into minerals – some energy is needed for the reaction.

The process normally takes thousands of years – the Swiss CarFix-technology only needs a few years for the mineralization of the greenhouse gas.

The reason for this unbelievable rate could be the special composition of basalt in the Earth crust below Iceland. Maybe metals like iron or aluminum help in the process.

Source: Climeworks.

The technology is simple: At Iceland’s Hellisheidi geothermal power plant, filters bind carbon dioxide from the air. Once a filter is saturated with CO2, it is heated to boiling point using waste energy from the geothermal plant. The gas is dissolved in water, which then is pumped down into a layer of basalt where mineralization takes place.

As the water comes up to the surface again, its is free of CO2.

At about 700 meters underground, the reaction with basaltic rock forms solid minerals such as calcite.

Yet until now, costs of this process are high.

The project at Hellisheidi has received funding from the European Union’s Horizon 2020 program.

A detailed description can be found in the „Quartz“ magazine.

Climeworks

Translation: pebe

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(13.11.2017, 11.13.2017)