10 Practical Ways To Capture Carbon Emissions.

Climate change has emerged as one of our generation’s most pressing issues, and the concentration of carbon dioxide has reached alarming levels.

We‘ve been flooding the atmosphere with way too much carbon, and merely switching power generation sources from fossil fuels to renewable energy may not be enough. The excess carbon also needs to be removed physically from the air. Let’s take a look at ten practical ways to do this…

Direct Air Capture

Somewhere in the world, most likely a power plant, machines are sucking carbon dioxide straight out of the air. The carbon dioxide is either stored underground or turned into fuels, building materials, and other products. It’s pretty exciting stuff!

There are around 15 plants operating worldwide, capturing more than 9000 tons of CO2/year. But direct air capture is not a silver bullet. At least, not yet.

While this tried-and-true technology can remove carbon dioxide from the atmosphere, its capture costs remain relatively high, making scaling extremely difficult.

Forests

This may seem like a silly idea, but the potential for carbon capture by the world’s forests is enormous. When they grow, trees absorb carbon dioxide from the air and transfer it to their trunks, roots, branches, and leaves through a process called photosynthesis.

Climate researchers suggest that increasing the Earth’s forests by an area the size of the United States could reduce atmospheric carbon dioxide by 25%. That is enough to offset almost 20 years’ worth of human-caused carbon emissions at the current rate. That’s not bad for something that’s basically free.

While this idea might seem appealing, it may have drawbacks of its own. Planting more than a half-trillion trees requires enormous effort, time, and money.

🎵Sounds like a big job for you and me, let’s plant a trillion trees!

Seaweeds

Most people don’t give much thought to seaweed, the plant-like material that grows in the ocean, freshwater lakes, and rivers — washes up on the beach, and stinks. You may have even eaten dried, savory seaweed snacks from the grocery store or sprinkled seaweed on your poke bowl.

Like land plants, seaweeds use photosynthesis to convert carbon dioxide into seaweed biomass. That may not seem like much, but seaweeds are incredibly efficient at sucking up carbon and using it to grow. Kelp, for example, can grow by as much as 2 feet (± 60 centimeters) per day, sucking up CO2 at an incredible rate.

Once the CO2 has been locked up in seaweed biomass, it can be harvested for use, sunk to the seafloor, or stored underground where all excess CO2 originated.

These “blue carbon” ecosystems can absorb 20 times more CO2 from the atmosphere per acre than land-based forests. The secret to their carbon-storing success lies not only in the plants themselves but also in the rich muck in which they grow. As marine plants grow and die, their leaves, roots, stems, and branches become buried in the seafloor, where they can store CO2 for decades or longer.

Bioenergy with Carbon Capture and Storage

Some climate researchers believe that one of the most sustainable forms of energy may be right under our feet. It’s known as bioenergy with carbon capture and storage (BECCS).

BECCS crops absorb CO2 from the atmosphere as they grow, and when they are converted into heat, electricity, or liquid or gas fuels, the resulting CO2 emissions are captured and stored for long periods of time.

Although BEECS appears to be the most scalable, well-established negative-emissions technology, its risks are still unquantifiable. For it to scale sustainably, emissions from the growing, harvesting and processing of crops must not outweigh the captured carbon, and storage must be reliable over long time periods.

Enhanced rock weathering

Farming can be a major source of anthropogenic CO2 emissions due to all of the fossil fuels used in the growing, harvesting, and processing of crops. However, a recent study suggests that crushing rocks such as basalt and spreading them on farmland could increase yields and absorb billions of tons of carbon.

This rock dust technique, known as enhanced rock weathering (ERW), has several advantages. To begin, many farmers already add limestone dust to soils to reduce acidification, and adding other rock dust improves fertility and crop yields, implying that ERW could become routine and desirable.

Climate researchers have long recognized that highly reactive basaltic rocks could be the best carbon mineralization solution, as it contains high concentrations of calcium and magnesium ions that chemically react with CO2 to make calcite, dolomite, and magnesite. In addition, many mines already produce it as a byproduct, and stockpiles already exist.

Furthermore, by dissolving CO2 in water aboveground and then injecting it into the subsurface, basalts avoid the slower and less secure stages of traditional carbon storage. However, this method alone cannot store or mineralize a large enough volume of CO2 to meet the planet’s carbon storage demand.

Cover Crops

While other carbon capture methods are still being researched and tested, cover crops have been around for more than a decade. These crops, which are typically grown in the off-season, have the potential to not only reduce farm carbon footprints but also improve soil health while providing farmers with an additional revenue stream.

Cover crops, like forests and biomass, remove CO2 from the atmosphere through photosynthesis. Their roots and shoots provide food for bacteria, fungi, earthworms, and other soil organisms, increasing soil carbon levels over time.

Corporations such as Microsoft and governments large and small are investing millions of dollars in cover-crop carbon capture initiatives. California is leading the way, having already paid some of its “carbon farmers” to reduce their greenhouse gas emissions, but some scientists are skeptical that these efforts will actually help slow global warming.

As a natural carbon sink, agricultural soils have the potential to store more than double the amount of carbon in our atmosphere and three times the amount in soil-based vegetation.

Microalgae

Microalgae are increasingly recognized as one of the most productive biological systems for generating biomass and capturing carbon, with efficiencies as high as 90% in open ponds.

Algae, like other plants, absorb carbon dioxide during photosynthesis. While trees “consume” CO2 by “absorbing” carbon into their trunks and roots and releasing oxygen back into the atmosphere, algae replicate the process but “absorb” the carbon in the form of more algae. Furthermore, given its relative size, it consumes more CO2 than trees because it can cover more surface area, grow faster, and be more easily controlled by bioreactors.

However, when algae take over a waterway, the consequences can be disastrous. The bloom can suffocate other plant and animal life, resulting in a dead zone, but when combined with AI-powered bioreactors that control water flow and light exposure to regulate algae growth so it doesn’t spill out of the container without constant supervision, algae can be up to 400 times more efficient than a tree at removing CO2 from the atmosphere.

When used correctly, it has the potential to make a city carbon-negative without changing its current production or consumption patterns, and it can be harvested for use in fertilizer, animal feed, fuel, biomass, and even human dietary supplements.

Carbon Absorbing Construction Materials

One of the world’s largest industries and a major source of greenhouse gas emissions may be taking steps to combat climate change. Concrete, which is widely used to support ongoing construction and infrastructure projects such as roads, bridges, skyscrapers, and other structures, is primarily made from portland cement, whose production causes direct emissions due to calcination, a process that converts heated limestone into calcium oxide and CO2, which are then released into the atmosphere.

Scientists in industry and academia are rigorously testing alternative cement formulations and materials to see if they are widely available, cost-effective, strong, and long-lasting. Some of these approaches, which are now being commercialized, include using waste products from other industries as well as nonstandard cement components that do not undergo CO2-emitting reactions during the manufacturing process.

CarbonCure, a Canadian startup, injects captured CO2 into concrete as it is being mixed. Once the concrete hardens, the carbon is permanently sequestered. Even if the building is demolished, the carbon remains. This is because it reacts with the concrete and transforms into a mineral. This process is known as cement carbonation, and it represents a significant carbon sink that is not currently accounted for in emissions inventories.

Hempcrete, a bio-composite material made of hemp hurds and lime, is another well-known approach. Like other plant products, hemp absorbs CO2 from the atmosphere through photosynthesis, retaining carbon while dissipating oxygen. It is ten times stronger than concrete but weighs only one-sixth as much, and it is the only well-established building material capable of removing carbon from the atmosphere. It is also a relatively safe material because it uses fewer pesticides and herbicides, resulting in less pollution from toxins in the fields. It is gradually but steadily gaining popularity as a preferred building material among those looking for a sustainable and cost-effective option.

Metal-Organic Frameworks

Metal-organic frameworks (MOFs), a new class of highly absorbent nanoporous materials, have emerged as a promising material for carbon capture in power plants.

MOFs are essentially crystals with a lot of tiny holes that enable them to trap large amounts of CO2 within their structures. The CO2 molecules pack themselves tightly into these tiny pores, forming weak bonds that can be broken later to extract the absorbed gas.

Nanostructures made from naturally occurring ingredients such as sugar, salt, and alcohol are the most promising MOFs. They have a significant advantage over other MOFs that, while also effective at absorbing CO2, are typically made from materials derived from crude oil and contain toxic heavy metals.

These materials outperform any commercially available option at high (5–10 bar) pressures, such as those found in coal gas plants, and have a high capacity for CO2 capture while remaining stable, affordable, and scalable.

Electro Swing Absorption

The electro-swing cell is a new battery-type device developed by researchers at the Massachusetts Institute of Technology (MIT).

The electrochemical cell can remove carbon dioxide from the atmosphere and release it in a pure, concentrated form.

It selectively captures CO2 when the material is negatively charged and releases it for storage when that charge is removed. Moreover, it operates at room temperature and pressure and requires no large-scale equipment because it is as efficient at 0.6 percent CO2 concentrations as it is at 10%, a typical power plant concentration. Amazing right?

The researchers plan to build a pilot-scale plant within a few years, with project capital and operating costs estimated to be between $50 and $100 per ton of CO2 captured.

What Are Your Thoughts?

What was your favorite method, and why? Mine is the microalgae technique because the algae can be harvested and used to make fertilizer, animal feed, fuel, biomass, and even human dietary supplements.

Carbon-absorbing construction materials came in second place for their potential use in ongoing construction and infrastructure projects like roads, bridges, skyscrapers, and other structures.

And planting a trillion trees sounds fun 🤔