Concrete Is One of the World’s Worst Pollutants. Making It Green Is a Booming Business. - Kanebridge News
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Concrete Is One of the World’s Worst Pollutants. Making It Green Is a Booming Business.

The material accounts for more than 7% of global carbon emissions, according to some estimates

By KONRAD PUTZIER
Wed, Mar 13, 2024 8:53amGrey Clock 3 min

Bill Gates , Jeff Bezos and former Los Angeles Laker Rick Fox are part of a new wave of investors and entrepreneurs looking to make one of the world’s worst pollutants greener.

Concrete accounts for more than 7% of global carbon emissions, according to some estimates. That is roughly the same as the CO undefined produced by all of India and more than double the amount produced by the global aviation industry.

Most of those emissions are caused by cement, the glue that binds together sand and gravel to make the concrete used to build roads, bridges and tall buildings.

Concrete, the second-most-used material in the world after water, is popular because it is cheap, relatively easy to produce, fire-resistant and extremely strong.

“It’s the most democratic material,” said Admir Masic , an associate professor of civil and environmental engineering at the Massachusetts Institute of Technology.

It is also very, very dirty. Cement is made by heating limestone and clay at around 2,700 degrees Fahrenheit in giant kilns and turning them into marble-sized granules called clinker, which are then turned into a powder and mixed with other materials. As it heats up, the limestone releases a lot of CO undefined , and the whole process is often powered by fossil fuels such as coal or gas.

Big cement producers and startups including Brimstone and Partanna, a startup based in the Bahamas and headed by three-time NBA champion Fox, are developing new technologies to produce cement while producing less CO undefined . Breakthrough Energy Ventures, which was founded by Gates and is backed by Bezos, Jack Ma and Michael Bloomberg among others, Fifth Wall and other venture firms have poured tens of millions of dollars into these companies.

These companies are being motivated in part by the federal government, which is dishing out grants and setting aside billions to decarbonise materials such as cement. Local regulators are also encouraging these new technologies. California in 2021 passed a law to cut emissions from cement and New York in 2023 issued rules that limit emissions on concrete used in state-funded construction projects.

Some companies are trying to make cement from different materials that are less polluting. Brimstone said it developed a way to make cement from rocks that contain no carbon. The company said it has raised around $60 million in venture funding to date.

Others are selling substitutes for cement so that concrete mixers need less of it. Eco Material Technologies, for example, harvests coal ash from landfills and volcanic ash from mines and sells it to concrete mixers. These substitutes aren’t new, but the company says it has worked out ways to increase its share in concrete.

“Our goal is to be able to use the last several generations of trash as the next several generations of greener concrete,” said CEO Grant Quasha .

Still others are removing pollutants from the air. The Halifax, Nova Scotia-based startup CarbonCure came up with a process to pump CO undefined into concrete as it is being made and raised $80 million in venture funding this past year.

CarbonCure pumps CO2 into concrete as it is being made. PHOTO: KENT NISHIMURA FOR THE WALL STREET JOURNAL

Partanna, which uses brine from saltwater desalination to make concrete, said homes made from its material suck carbon out of the air.

It is unclear if the greener concrete alternatives will ever catch on broadly. Building codes have rigid rules on what concrete must contain, and many builders don’t like to try out new materials, Masic said.

Cost is another issue. Eco Material’s most environmentally friendly cement alternative, for example, costs around twice as much as standard cement, according to Quasha. CEO Cody Finke said Brimstone’s cement will be as cheap or cheaper than the common sort, but the company has yet to build a factory.

“If I go to the developing world and tell them you’re going to have to pay 20% more for your cement, they won’t do it,” said Eric Toone , a managing partner at Breakthrough Energy Ventures.

Even if some of these new technologies succeed, the startups have yet to prove that they can produce green cement at the vast quantities needed to make a dent in global warming.

Still, Toone said cement makers have no choice but to find cheap ways to cut emissions because ditching the material isn’t an option.

“Cement is sort of this wonder material,” he said. “It’s so cheap, it’s so valuable, it’s so good for what we need that it’s really hard to think of ways around it.”



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Idaho is not a place that’s often associated with Medieval castles, but a pair have just hit the market for $6.25 million.

The imposing stone structures have towers, turrets, ramparts, arrow-slit windows and even a drawbridge, and might just be the most authentic-looking castles this side of the Atlantic.

“Who expects to see a castle like this in Idaho?” said listing agent Brenda Burk of Coldwell Banker Schneidmiller Realty, who brought the property to the market last week. They are, she said, “extremely unusual.”

Schweitzer Castle and Château de Melusine, as they’re known, stand within Schweitzer Mountain Resort in the Selkirk Mountains and overlook the nearby mountain resort town of Sandpoint. They take in panoramic views of Lake Pend Oreille, Idaho’s largest lake.

The pair of ski-in/ski-out homes each have three bedrooms, two bathrooms and three stories, Burk explained. They are “so authentic,” she said. “Every single stone was handlaid.”

Schweitzer Castle, she said, wasn’t built for “functionality,” but has been modernized and adapted and now has everything a 21st-century residence requires, along with a dungeon, which for some buyers may also be a requisite.

The chateau, meanwhile, has a hot tub room with mountain views, as well as a garage.

The property is being sold furnished, and will come complete with the hand-carved statues, armor, mounted swords, stained-glass windows and a host of antiques dating to the 15th and 16th centuries.

The owner, an antique collector who couldn’t be reached for comment, “is always looking for that hidden jewel and he found that here,” Burk said.

The next custodian is likely to stem from a varied pool of buyers, Burk said, that would include “the trophy-home buyer, someone who can say ‘I own a castle.’”

The property could also appeal to someone looking for a vacation home, or a multi-generational estate, and beyond that “there’s the dreamers,” she said. “We definitely try to market to people who like Medieval history or maybe do Renaissance fairs.”

The seller “really wants it to go to someone with the same passion.”