It’s not enough to just capture the carbon, you also have to “lock it up”!

You know, it is difficult to preserve the gas in large quantities for a long time over a hundred years through artificial facilities, so it needs to be sealed. The best way is to return carbon dioxide to its original form, that is, to become a component of various biological and non-biological organisms. The biological method is very common, just plant trees.

Although trees also exhale carbon dioxide, more carbon dioxide is formed during the growth of plants, and carbon is fixed in the roots, stems, leaves, flowers, fruits, and seeds of plants. But the problem is that we don’t have so much space to plant trees. On the contrary, we are still cutting down trees for animal husbandry, farming, mining, and real estate development.

So today, when we collect carbon dioxide and seal it on a large scale, we inject it into oil and gas fields. This idea is easy to understand. Oil and natural gas are a mixture of gas and liquid. They have been deposited in oil and gas fields for tens or millions of years. There has been no leakage for millions of years, so if we store carbon dioxide back, wouldn't it also be possible to achieve the same effect of preventing leakage?

In fact, there really is a natural gas storage site there, which is not only tight and safe, but also has enough storage space. Especially since it is evenly distributed around the world, these pits are everywhere, ready-made, and there is no need for geologists to explore where to store gas, nor to use large machinery to dig. Carbon capture has just begun, and those oil and gas fields are enough for decades. And this method has another clever thing, it is not only the main way to store carbon dioxide, but also the main way to reuse it after capture.

This technology is called "CO2 flooding". Q: How is the oil pumped up from underground? A: Only in the Middle East, which is rich in oil, can you drill a deep hole, then inject water into it, and the oil will gush out. In oil fields in other regions, the oil is actually embedded in the cracks of the rock formations, and some methods are needed to get it out.

These include the use of hydrocarbons, chemical drives, thermal drives, and carbon dioxide drives, using high pressure to drive the oil out. Among them, carbon dioxide drives are very effective because they can dissolve in oil. After dissolving, they also greatly reduce the viscosity of the oil and expand its volume, making it easier to flow out.

Since oil extraction requires injecting a large amount of carbon dioxide into the oil field, where does this carbon dioxide come from? Why not just capture it? So a lot of carbon dioxide not only helps people extract oil, but is then sealed in the big pit after the oil flows away.

There are 43 carbon dioxide storage projects with a storage capacity of 1-9 million tons in the world. All of them are geological storage, 18 of which have been built, 5 are under construction, and 20 are under planning and construction.

Of those that have been built, the longest one has been in existence for more than ten years, and there has not been a single leak. However, the requirements for sealing are very stringent. It is best to seal it permanently, and if it cannot be sealed permanently, it must not leak for thousands of years. However, this is difficult to verify, and we can only store it and watch it. Not to mention that there are many factors that will interfere with the sealing effect, such as earthquakes, which cannot be prevented.

In addition, the second largest storage method is to seal carbon dioxide in the water-bearing strata on the seabed. It doesn't have to be too deep or too far, just about 800 meters below the sea surface is enough, that is, the continental shelf. Because the continental shelf is always soaked in seawater, the strata a few hundred meters below the seabed contain a lot of water. Water can accommodate carbon dioxide, so just pump carbon dioxide into the strata on the shallow seabed. Now, more than 20 million tons of carbon dioxide have been sealed. Although this part cannot be reused, no leakage has been found.

Carbon emissions are related to each of us, and no one can stay out of it. On the bright side, if you are still hesitant about your career choice, why not join this great cause that is destined to rewrite history?