Spurred on by reducing costs, improving "investability" and increased political support, many companies are realising the dream being able to literally suck greenhouse gasses out of the air.

There's a few companies operating in this space, some turn the CO2 into other fuels, some tucking it away in places where it won't do harm and will eventually re-integrate with the planet.

With that said, sucking carbon dioxide from the air (or as it is officially known, Direct Air Capture) is still an expensive technology, and the energy required to do it can generate more CO2 emissions that it cleans.

The cost of removing carbon dioxide from the air through planting trees costs between $50-60 per tonne of CO2 sequestered. However, due to the amount of energy required for Direct Air Capture ("DAC"), the cost of this approach varies between $90-$600 per tonne, which is substantially more, and comes with the oxymoronic risk of being potentially CO2 net positive.

For this reason, Climeworks' technology addresses the energy requirement differently.

To simplify the DAC process, you can think of it like this:

Giant fans, suck in air, capturing CO2 in special filters, then heating these to 100°C to separate the CO2 and leaving purified air to go back into the environment.

The most energy intensive part of the DAC process is heating the CO2-laden filters. The theoretical minimum energy consumption for this is 250kWh per tonne of CO2.

A typical UK household consumes approximately 10kWh per day, and generates between 17.1 and 20.2 tonnes of CO2 per year. So to eliminate the CO2 production of a typical house, a DAC plant would need to consume at least 4,725 kWh, which is a ~1000kWh more than the household it is trying to compensate for would generate in the year.

Therefore one of the key requirements for a commercially and environmentally viable carbon sequestration DAC venture is to find energy sources that are abundant, without needing to burn additional energy.

Climeworks have built their technology to use waste, or naturally occurring heat sources to power their system.

Taking their energy from the exhaust heat of incinerator plants, or the geothermic heat of volcanic activity, Climeworks claim to be able to drastically reduce the requirement for generated power to the point where their facilities are operating at net-negative levels.

Their initial plant in Switzerland aims to capture up to 900 tonnes of C02 per year, and the deployment in Iceland, which now had the backing of Audi, pushes this to 2,500 tonnes per year. But they're not stopping there, there's another plant in Italy and more in the works to help them reach their target of scrubbing 1% of the global CO2 emissions per year.

What do you think?

Do you think this is a worthwhile avenue of development? Will the investment pay off? Are there better innovations for carbon sequestration? Leave a comment below to let me know your opinions.