The world is banking on giant carbon-sucking fans to clean our climate mess. It’s a big risk.

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From CNN
Iceland (CNN)The windswept valleys surrounding the Hengill volcano in southwestern Iceland are dotted with hot springs and steam vents. Hikers from all over the world come here to witness its breath-taking scenery. Even the sheep are photogenic in the soft Nordic light.

Right in the middle of all that natural beauty sits a towering metal structure resembling four giant Lego bricks, with two rows of six whirring fans running across each one. It’s a contraption that looks truly futuristic, like something straight out of a sci-fi film.
Humans have emitted so much carbon dioxide (CO2) into the atmosphere that machines like this are being used to literally suck the gas back out, like giant vacuum cleaners, in an attempt to slow the climate crisis and prevent some of its most devastating consequences.

It opened last month and currently removes about 10 metric tons of CO2 every day, which is roughly the the same amount of carbon emitted by 800 cars a day in the US. It’s also about the same amount of carbon 500 trees could soak up in a year.

It’s a fine start, but in the grand scheme of things, its impact so far is miniscule. Humans emit around 35 billion tons of greenhouse gas a year through the cars we drive and flights we take, the power we use to heat our homes and the food — in particular the meat — that we eat, among other activities.

All this CO2 accumulates in the in the air, where it acts like the glass of a greenhouse, trapping more heat in the atmosphere than Earth has evolved to tolerate.
That’s where the technology used for Orca, called carbon capture and storage (CCS), comes in.

How the ‘magic’ happens

The Orca machines use chemical filters to capture the heat-trapping gas. The “fans,” or metal collectors, suck in the surrounding air and filter out the CO2 so it can be stored.
Carbon dioxide’s concentration in Earth’s atmosphere has likely not been this high at any other point in the last 3 million years, according to NASA scientists. But at levels over 410 parts per million, to actually capture a meaningful amount of CO2, a huge amount of air needs to pass through these machines.

“What is happening is that CO2 in the air is an acid molecule and inside the collectors we have alkaline. Acids and alkaline neutralize each other,” Climeworks co-CEO Christoph Gebald told CNN. “That’s the magic that happens.”

In two to four hours, the surface of the filter is almost completely saturated with CO2 molecules — as if there are “no parking slots left,” as Gebald puts it.
“Then we stop the airflow and we heat the internal structure to roughly 100 degrees Celsius, and at that temperature, the CO2 molecules are released again from the surface, they jump off back to the gas phase and we suck it out.”

Because of the high temperature that is needed for the process, the Orca plant requires a lot of energy. That’s a problem that’s easily solved in Iceland, where green geothermal power is abundant. But it could become a challenge to scale globally.

The machines at Orca are just one way to remove CO2 from the air. Other methods involve capturing the gas at source — like the chimney of a cement factory — or removing it from the fuel before combustion. That involves exposing the fuel, such as coal or natural gas, to oxygen or steam under high temperature and pressure to convert it into a mixture of hydrogen and CO2. The hydrogen is then separated and can be burned with much lower carbon emissions. However, methane emissions could be a problem when the process is used on natural gas.

The carbon that comes out of CCS can be used for other purposes, for example to make objects out of plastic instead of using oil, or in the food industry, which uses CO2 to put the fizz in drinks. But the amount that needs to be captured vastly exceeds the world’s demand for CO2 in other places, which means the majority of it will need to be “stored.”

For the full story, including some good video and visuals, including some provocative ideas for funding CC and S click on this hot link The CNN Report on this

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