Carbon management is set in stone | MIT News

Keeping global temperatures within limits deemed safe by the Intergovernmental Panel on Climate Change means doing more than reducing carbon emissions. This means reversing them.

“If we want to be anywhere near these limits [of 1.5 or 2 C]then we need to be carbon neutral by 2050 and then carbon negative after that,” says Matěj Peč, geoscientist and Victor P. Starr assistant career development professor in the Department of Earth, Atmospheric, and Earth Sciences. planets (EAPS).

Going negative will require finding ways to dramatically increase the world’s ability to capture carbon from the atmosphere and put it somewhere it won’t come back. Carbon capture and storage projects already suck up tens of millions of metric tons of carbon every year. But reducing emissions will mean capturing several billion more metric tons. Today, people emit about 40 billion tons of carbon every year around the world, mostly by burning fossil fuels.

Due to the need for new ideas in carbon storage, Peč created a proposal for the MIT Climate Grand Challenges competition – a bold and radical effort by the Institute to support paradigm-shifting research and innovation to make in the face of the climate crisis. Called the Advanced Carbon Mineralization Initiative, his team’s proposal aims to bring together geologists, chemists and biologists to make the permanent storage of carbon underground exploitable under different geological conditions. This means finding ways to speed up the process by which carbon pumped underground is turned into rock or mineralized.

“That’s what geology has to offer,” says Peč, who leads the project, along with Ed Boyden, professor of biological engineering, brain and cognitive sciences, and media arts and sciences, and Yogesh Surendranath, professor of chemistry. “You’re looking for places where you can safely and permanently store these huge volumes of CO2.”

Peč’s proposal is one of 27 finalists selected from a pool of nearly 100 Grand Climate Challenge proposals submitted by collaborators across the Institute. Each finalist team received $100,000 to further develop their research proposals. A subset of finalists will be announced in April, constituting a portfolio of multi-year “flagship” projects with additional funding and support.

Building industries capable of becoming carbon negative presents enormous technological, economic, environmental and political challenges. For one thing, it’s expensive and energy-intensive to capture carbon from the air with existing technologies, which are “extremely complicated,” says Peč. Much of the carbon capture going on today is focused on more concentrated sources like coal or gas-fired power plants.

It is also difficult to find geologically suitable sites for storage. To keep it in the ground after being captured, the carbon must either be trapped in airtight reservoirs or turned into stone.

Iceland is one of the best places for carbon capture and storage (CCS), where a number of CCS projects are running. The island’s volcanic geology helps accelerate the mineralization process, as carbon pumped underground interacts with basalt rock at high temperatures. In this ideal setting, says Peč, 95% of the carbon injected underground is mineralized after just two years – a geological flash.

But the geology of Iceland is unusual. Elsewhere, deeper drilling is required to reach suitable rocks at an appropriate temperature, adding cost to already expensive projects. Also, says Peč, there is not a complete understanding of how different factors influence the rate of mineralization.

Peč’s Climate Grand Challenge proposal would study how carbon mineralizes under different conditions, and explore ways to accelerate mineralization by mixing carbon dioxide with different fluids before injecting it underground. Another idea – and why there are biologists on the team – is to learn from various organisms adept at turning carbon into calcite shells, the same thing that makes up limestone.

Two other carbon management proposals, led by EAPS Cecil and Professor Bradford Hager of Ida Green, have also been selected as Climate Grand Challenge finalists. They focus on both the technologies needed to capture and store gigatons of carbon as well as the logistical challenges involved in such a huge undertaking.

It involves everything from choosing the right sites for storage to regulatory and environmental issues, as well as how to bring disparate technologies together to improve the entire pipeline. The proposals focus on CCS systems that can be powered by renewable sources and can dynamically meet the needs of different hard-to-decarbonise industries, such as concrete and steel production.

“We need an industry on the scale of today’s oil industry that will do nothing but pump CO2 into storage tanks,” says Peč.

For a problem that involves capturing huge amounts of gases from the atmosphere and storing them underground, it’s no surprise that EAPS researchers are so involved. Earth science has “everything” to offer, says Peč, including the good news that Earth has more than enough places where carbon could be stored.

“Basically, the Earth is really, really big,” says Peč. “Reasonably accessible places, close to continents, store somewhere on the order of tens of thousands to hundreds of thousands of gigatons of carbon. That’s orders of magnitude more than we need to reinvest. »

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