World's first negative emissions plant turns carbon dioxide into stone

Scientists and people around the world are concerned with the amount of carbon dioxide that we put into the atmosphere globally each year. The fear is that the greenhouse gas could warm the planet enough to cause a catastrophic climate disaster. Work has been ongoing for decades into systems that can capture the CO2 from the air and help the environment.

A company called Climeworks has announced that on October 11 a geothermal power plant in Iceland was the first plant that is able to perform something called direct air capture and verified to achieve negative carbon emissions. The plant is still at a pilot scale and captures 50 metric tons of CO2 from the air each year. That is said to be the same amount produced by a single US household yearly.

The carbon dioxide emissions are converted into stone preventing it from escaping back into the atmosphere for millions of years. Current CO2 capture systems use a process called "reversible absorption" to remove the CO2 gas from the air. Climeworks and Global Thermostat have systems that coat plastics (Climeworks) and ceramics (Global Thermostat) with a chemical that absorbs CO2. The companies say that it is too early in development to predict what the process will cost at scale.

The goal of Climeworks is to bring the costs down to about $100 per metric ton of carbon dioxide captured. Global Thermostat wants to see that cost at around $50 per metric ton. The plant where the technology is being demonstrated by Climeworks is located in Hellisheidi, Iceland. It uses naturally occurring heat from a volcanically active area to produce electricity and heat. It makes about 300MW of electricity and about 130 MW of heat.

The emissions are cleaned using a process that injects the CO2 mixed with water underground where it reacts with the basaltic rock Iceland sits on to form minerals. The forming of these minerals usually takes thousands of years, but the CO2 capture process has allowed the mineralization to happen in less than two years. This locks the CO2 into the rock and prevents it from entering the atmosphere for millions of years. This tech and the process makes the hydrothermal power plant the world's first verified negative emissions plant.