Turning Excess CO2 Into a Rock
There are only two approaches to dealing with climate-damaging Carbon Dioxide emissions: don’t emit them at all or trap them before they escape.
Becoming more energy-efficient and deploying clean renewable energy sources like solar, wind, tidal, and hydroelectric power covers the first one. But doing safe and efficient CO2 trapping seemed impossible until now.
The latest climate change innovation to hit the planet comes from of all places, Iceland, where 85% of all energy use there is produced by geothermal heat, hydropower, and a few other renewable options. But even in Iceland, where hot volcanic rocks provide the raw energy behind the country’s geothermal power, there have been carbon dioxide emissions coming out in the steam and escaping into the air.
The new innovation to deal with those emissions grew out of project called Carbfix. It was launched in 2007 by Iceland’s Reykjavik Energy, the owner-operators of the 303 MW Hellisheidi plant, one of the largest geothermal plants anywhere.
The goal was straightforward, the idea of pulling the carbon dioxide and also dangerous hydrogen sulfide emissions out of the exhaust chain, and then shoving the dangerous materials back into the ground. The problem is that although pushing the gases back down is not that hard, keeping them there is a challenge.
What the scientists did to handle that was first to dissolve the dangerous gases into large quantities of water, followed by second to inject that watery mixture into porous basalt, a volcanic rock that forms naturally when lava cools. With the help of the basalt and the massive amounts of water, a chemical reaction ensues that converts the potentially leaky carbon dioxide emissions into a solid carbonate by binding it with either calcium, iron, or magnesium, all materials that naturally show up in basalt compounds throughout the world.
The end result is the originally dangerous carbon dioxide emissions have been literally turned into rock. These were gases that even if they were pushed back in the ground would have likely migrated back out in the future, adding once again to global warming.
The carbon-trapping process happens very quickly and with remarkable efficiency. In the Iceland research site where the process is under evaluation, the carbon dioxide becomes mineralized quickly and at an over 95% conversion rate. And these rocks, when formed, stay in that form for a very long time.
Having already achieved success in test runs, Reyjavik Energy is now gearing up to handle as much as 10,000 tons of CO2 conversion into basalt per year soon. The plant currently produces 40,000 tons of emissions per year, which puts it on a path to 100% conversion not too long from now.
It is not yet clear all this could mean to the rest of the world. The U.S., for example, spits out more than 5 billion tons of carbon dioxide per year, and the systems to integrate basalt-based carbon capture may not work so well because of logistics, among other things. But the solution is still a major and positive development in a world hoping for new answers to the climate change dilemmas facing us all.