Carbon Capture. And then what?

Climate change and global warming are all things most of us have heard of and know about in today’s digital world. But, the journey in controlling it is going at a much, much slower rate than posts passing through, not just social media, but even slower than posts through the post office.

But, what if there was a way to add a catalyst to that process? The addition of greenhouse gases into the atmosphere is what causes global warming. Suppose we had a way to remove it from the air? A way that does not involve trees. Because the amounts of carbon released today far exceed the amounts that trees can absorb from the air. Let’s start with a couple of questions:

What is Carbon Capture and Storage?

Carbon capture and storage (CCS) is the process of absorbing waste carbon dioxide (CO2) from the atmosphere. This is usually done near places with large sources of pollution. The CO2 is then stored at storage sites. This is to make sure that it cannot enter the atmosphere. The storage process involves storing it deep underground in geological formations. Which are basically rocks!

Why is CCS needed?

Ever since the industrial revolution, humanity has added greenhouse gases into the atmosphere. And at higher rates every year. Rates that are drastically increasing. And as we know, these greenhouse gases cause global warming.

Talks about mitigating climate change, generally revolve around ideas like renewable energy. But these solutions only reduce our current emissions. Such talk about climate change must also take into account the existing greenhouse gases up there. Those lovely organic molecules floating up there? They are the ones making the earth heat up.

Which is where CCS comes into play. Capturing excess CO2 from the atmosphere reduces the rate at which the greenhouse effect works. Thereby slowing global warming.

In my previous post, I touched on some of the means available to capture and store carbon. In this one, I figured I would explain those, a little more in detail.

Methods of Carbon Capture

So now we are pulling CO2 out from the atmosphere. Well, there are a couple of different ways to do this.

Direct Air Capture

This is among the more effective means of absorbing carbon. A newer piece of technology called Direct Air Capture (DAC).

In this process, a stream of CO2 filled air is passed through an alkaline medium. This medium absorbs the CO2 present in that air.

Next, this alkaline medium is heated to produce a stream of concentrated CO2 gas. This gas is then dehydrated and compressed.

Simply speaking, this CO2 can then be used in two ways.

First, it can be used to generate energy. In this way, we are reducing, or even completely cutting out the usage of fresh fossil fuels. Thus preventing new CO2 from entering the atmosphere. However, with this we aren’t going carbon negative, only carbon neutral. Which is pretty much the same as what we are doing with other types of renewable energy sources.

Second, the CO2 can be sequestered (stored) deep underground in geological formations.

Unfortunately today a lot of DAC plants are generally located or even run by heavy industrial plants that are run on fossil fuels. So what these DAC plants are pretty much doing, again, are only going carbon neutral. NOT carbon negative. They are only removing the fresh carbon these fossil fuel-run plants are giving out. Not the carbon that is already out there.

To go carbon negative we have to remove more carbon from the atmosphere that we are currently putting out there.

For that, DAC is a tool with enormous potential to help achieve this goal. Unfortunately, it isn’t a magic bullet to climate change. Not only is DAC a tool that is more carbon-neutral than negative, but it is also an extremely expensive method.

Bio-energy with carbon capture and sequestration (BECCS)

This is another, potentially effective method of pulling CO2 out of the atmosphere. BECCS is a means of absorbing carbon from the air using biomass, such as algae, during their growth. This biomass is then burned in a thermal power plant to generate energy. The CO2 released by the biomass, is collected at the exhaust and then sequestered deep underground.

There is a difference in impact with this type of carbon capture. Here, we are reducing the net atmospheric carbon, thus going carbon negative. And this is while also being able to generate a certain amount of energy. So it certainly seems like it is a win-win. Unfortunately, this method, like DAC, is expensive.

Geological storage of captured carbon

Now, the most viable way of storing carbon would be via geological storage.

The process of storing CO2 into deep, underground geological formations is called Geological storage.

Initially, the CO2 is kept in a form where there is no sharp line of difference between the liquid and gaseous CO2. This form is called the supercritical form . Then, this supercritical CO2 is injected into geologic formations(rocks) that have a low level of permeability. That way, the CO2 cannot directly rise up into the atmosphere. While trapped under there the CO2 stays stored in a couple of different methods. If the CO2 reacts with aqueous liquids found there, it ultimately dissolves into these liquids. This is called solubility trapping.

The CO2 can also react with either the minerals or the organic matter found under there to effectively keep it in place. This is called mineral trapping.

These CO2 storage sites can include places like oil fields, gas fields, saline fields… and coal seams that cannot be mined.

Thankfully too! We don’t need more places from which we can release carbon into the atmosphere!

Unfortunately, there is a devil in disguise technique used by a lot of oil companies today. They inject that carbon dioxide into oil fields currently being used to enhance oil recovery. This is NOT a means to go carbon negative. That injected carbon is later burnt, only to be released into the atmosphere again.

To add to that, this popular means of injecting carbon has a lot of high potential risks. The carbon stored has to be constantly monitored to make sure it does not rise to the surface. If it does, it is not only being unhelpful to curbing climate change. It could also lead to several kinds of disasters in that area like extreme pipe bursting and so on.

Another interesting form of geological storage is one being used by an Icelandic based company- Carbfix. They use the principle of converting CO2 into a solid by getting it to react with mineral-rich rocks. Conventionally, this is a process that can take well over thousands of years. But this company has developed a technique to do the same in about two years instead! CO2 is dissolved in water before injecting it into basaltic rocks abundantly found in Iceland. Basalt is actually the most common rock type found on the earth. From an interview with this company, they say that wherever basalt and water can be found, this technique can work. So it is actually quite a feasible method. You can check out this article if you want to understand it more in detail.

In conclusion…

When we run the statistics on CCS today, although what it shows us is very promising, it is quite expensive. There are only about 17 operating CCS projects in the world today.

Plus like I said earlier, DAC is not a magic bullet to solving climate change. Unfortunately, neither is BECCS, though it is also a good one. Today, we have various means of dealing with climate change. And from the CCS perspective using a combination of both DAC and BECCS will definitely act as a catalyst to reduce the carbon in the atmosphere. However, to truly curb global warming, we also have to cut down on our emissions. A large part of that depends on changing our lifestyles. That is something that is just not happening today. CCS may be a major aspect of dealing with climate change, however, it is only one aspect of it and there are a lot of other things that need to be done.