Carbon capture, storage, and removal: Why it’s hard, and some of the innovators who make it happen

Given the negative effects of CO2 emissions on our climate, it would be great if we could capture or remove CO2 from the atmosphere and the oceans. But what makes it hard to do this? And who are some of the companies and scientists who want to make it work? And who funds these activities?

Why is carbon removal and capture hard?

I have no background in chemistry. So I first had to find out why carbon (CO2) capture and removal are hard.

The short answer

Carbon capture is hard because you need a lot of energy. And it’s hard to capture the CO2 into something that remains stable, and doesn’t just fall apart and release the CO2 again.

The longer answer

Here is a schematic I made to illustrate my understanding of the process (click on the image to see it full size):

Carbon removal and capture is hard. One problem is the amount of energy required. Another is re-binding the CO2 to something that remains stable.
Carbon removal and capture is hard. One problem is the amount of energy required. Another is re-binding the CO2 to something that remains stable.

Let me walk you through the schematic:

You burn hydrocarbon fuel because you want to get energy. You want energy because you want to move something, for example. And “burning fuel” basically means you use O2 to oxidize your fuel. O2 is your oxidizer. Without oxidizer, you can’t burn fuel (that’s why rockets have to bring their own oxidizer: there’s no O2 or any other oxidizer in space).

Now, when you burn fuel this way, you get energy plus some other products. These other products are a lot of CO2, and some water (H2O) and other things. I won’t go into the water and the other things here. Not because they are not important but because I want to focus on the CO2 here.

Like I said, you get energy from burning fuel. Before burning your fuel, you had O2 and your fuel in high-energy state. Then you take out the energy by burning (oxidizing) the fuel. As a result, now the CO2 (and the other stuff) sits around in the atmosphere or the ocean, in a low-energy state. And that’s the problem: Now when you want to re-bind the CO2 to something, you have to lift it out of its low-energy state. In other words, you have to put energy into it. A lot. Plus, like I said above, you want the end product to be something that’s stable.

In order to discover and collect the results for this article, I used various ways to look for carbon capture companies and R&D in Mergeflow. In the video below, you can see one way–exploring data on public R&D funding:

How you can use Mergeflow to discover carbon capture companies in data on public R&D funding.

For this article, first, I did a general 360° search in Mergeflow, to get a first overview across venture investments, markets, patents, R&D, news, etc..

If you have a Mergeflow account, you can do this search by clicking here. If you don’t have an account, you can create one here, and then click on the search link.

I made a snapshot of some results:

"Carbon capture" results snapshot from Mergeflow. In addition to data from venture capital and markets, the report also contains insights from patents, science publications, news, blogs and publicly funded R&D projects.
“Carbon capture” results snapshot from Mergeflow. In addition to data from venture capital and markets, the report also contains insights from patents, science publications, news, blogs and publicly funded R&D projects.

First, some general trends in carbon capture R&D and business activities

Before we look at individual findings (companies and R&D), here are some general trends from the past ten years (for each screenshot, you can click on the image to see it in full size):

Venture capital investments in carbon capture and storage have increased recently

Venture capital investments in carbon capture technologies. Screenshot from Mergeflow.

Both science publications and publicly funded research projects have been strong for years

Here are science publications…

The number of science publications on carbon capture collected by Mergeflow from the past ten years.
The number of science publications on carbon capture collected by Mergeflow from the past ten years.

…and publicly funded research projects (click on the image to see it in full size):

Mergeflow data on publicly funded research projects in the US, UK, and the EU from the past ten years.
Mergeflow data on publicly funded research projects in the US, UK, and the EU from the past ten years.

Publicly funded research projects here include funding programs in the US, UK, and the EU.

Both technology blogs and industry news have increased more recently, similar to venture capital fundings

Here are technology blogs, along with some emerging technologies that Mergeflow identified in the blog post contents (“emerging” does not necessarily mean “new”)…

Technology blogs on carbon capture have been trending upward recently. The tag cloud shows emerging technologies that Mergeflow identified in the contents of the blog articles.
Technology blogs on carbon capture have been trending upward recently. The tag cloud shows emerging technologies that Mergeflow identified in the contents of the blog articles.

…and industry news:

Industry news on carbon capture have trended upward recently.  Screenshot from Mergeflow.
Industry news on carbon capture have trended upward recently. Screenshot from Mergeflow.

A short summary of these trends could be, “first, we saw R&D before commercialization started to kick in”.


Related: Using data to estimate tech maturity


Next, let’s look at individual findings, starting with some of the venture-funded companies.

Venture capital investments in carbon capture and removal companies

Let’s start with the most recent VC funding (it’s March 2022 as I write this), Sustaera.

Sustaera

Sustaera is a direct air capture company. “Direct air capture” means that they remove CO2 directly from ambient air (and not e.g. at stationary CO2 sources such as power plants). In December 2021, they raised $10Mio Series A from Breakthrough Energy Ventures, Grantham Trust’s Neglected Climate Opportunities and others.

They use renewable energy (remember, you have to up-shift the CO2’s energy level), natural minerals as sorbents (remember the “we want the captured CO2 to be stable” part), and a modular and therefore scalable technology architecture. While their website currently does not provide a lot of technological details, Mergeflow tells me that there are some patents by their parent company, Susteon:

CO2 CAPTURE SORBENTS WITH LOW REGENERATION TEMPERATURE AND HIGH DESORPTION RATES

PRODUCTION OF HIGH PURITY PARTICULATE SILICON CARBIDE BY HYDROCARBON PYROLYSIS

CONTINUOUS DESULFURIZATION PROCESS BASED ON METAL OXIDE-BASED REGENERABLE SORBENTS

The inventors listed in these patents are now on Sustaera’s team.

CarbonCapture

CarbonCapture, the name gives it away…

Like Sustaera, CarbonCapture is a direct air capture company. In 2021, they raised $35Mio Series A from Prime Movers Lab, Rio Tinto, Idealab Studio, TIME Ventures, and others.

Here is an illustration of CarbonCapture’s direct air capture process, from their webpage:

CarbonCapture's direct air capture process. Screenshot from their website.
CarbonCapture’s direct air capture process. Screenshot from their website.

If you want more details, here is a CarbonCapture patent:

A NOVEL APPROACH TO COST-EFFECTIVE CARBON CAPTURE FROM AIR BY PRODUCING CARBON-NEGATIVE WATER

C-Zero

In February 2021, C-Zero raised $11.5Mio from Breakthrough Energy Ventures, Eni Next, Mitsubishi Heavy Industries, and AP Ventures.

Here’s the idea behind C-Zero: Traditionally, in order to use natural gas as energy source, you would burn it. By contrast, C-Zero’s technology only uses the hydrogen that’s in the natural gas as energy source. And the carbon is extracted as a “dense solid”, in their words. Below is a schematic from C-Zero’s website:

C-Zero's process for converting natural gas into hydrogen and solid carbon. Image from C-Zero's website.
C-Zero’s process for converting natural gas into hydrogen and solid carbon. Image from C-Zero’s website.

From the schematic above, you can see that C-Zero’s technology does carbon capture, and indirectly can also do carbon removal.

Svante

Also in February 2021, Svante raised $75Mio Series D funding from Singapore-based Temasek, Chart Industries, Carbon Direct, and Export Development Canada.

Svante is a carbon capture company. Their technology captures carbon from flue gas, via nanotechnology-based proprietary filters. Flue gas is exhaust generated by industrial plants (cement or steel plants, for example).

According to their 2:13 min video (see below), their technology’s capital cost is less than half of existing technologies.

Carbon Clean Solutions

In July 2020, Carbon Clean Solutions raised $22Mio Series B funding from Equinor Ventures, ICOS Capital, WAVE Equity Partners, Chevron Technology Ventures and Marubeni Corporation.

Carbon Clean Solutions is a carbon capture company as well. They supply cement and steel plants, as well as refineries, energy from waste plants, and biogas (renewable natural gas) feeds.

They are currently developing modular systems that can be used out-of-the-box. This will make installation of their systems much easier, and therefore faster and cheaper. The schematic below from Carbon Clean Solutions’ website shows the process (click to enlarge):

Carbon Clean Solutions' carbon capture process. Screenshot of Carbon Clean Solutions' website.
Carbon Clean Solutions’ carbon capture process. Screenshot of Carbon Clean Solutions’ website.

Last Energy / OPEN100 / Energy Impact Center

In February 2020, Last Energy raised $3Mio funding, led by First Round Capital.

Last Energy is not a carbon capture or carbon removal company. Rather, their goal is to build modular nuclear reactors, based on an open-source design.

Now you’re probably asking yourself, “Why include a nuclear power company in an article about carbon capture and removal?”

Bret Kugelmass, who came up with the idea for OPEN100 (a project of the Energy Impact Center), argues that “nuclear is the only energy source that we could use to pull carbon from the air” (see this article in VentureBeat). In fact, making energy sources that can power carbon removal motivates what OPEN100 is doing. Bret Kugelmass talks about this in this 7-minute presentation (the remaining 8 minutes of the video are Q&A):

Bret Kugelmass, founder of OPEN100, talks about

OK, next, let’s switch perspective a bit and look at public R&D funding of SMEs.

Public research funding of carbon capture and removal SMEs

Mergeflow tracks public R&D funding from across a number of organizations and geographies. For discovering early-stage SMEs, I recommend checking out the SBIR (Small Business Innovation Research) program. This is because SBIR funds individual companies, not consortia, which makes it a lot easier to pinpoint who really does the work.


Related:


Here is an overview table of carbon capture and removal SBIR fundings since beginning of 2020 (click to enlarge):

Carbon capture and removal SBIR fundings. Community Energy and Verdox each were awarded two SBIR grants. Screenshot from Mergeflow.
Carbon capture and removal SBIR fundings. Community Energy and Verdox each were awarded two SBIR grants. Screenshot from Mergeflow.

Community Energy

In 2020, Community Energy got an SBIR grant to develop an improved chemical process for carbon mineralization. In carbon mineralization, the CO2 reacts with minerals that contain magnesium or calcium. The result is a solid carbonate. This carbonate can then be used as building material, for making cement, for example. This is important because the cement industry currently is a big contributor to CO2 emissions (8% of global CO2 emissions, according to Bloomberg).

The principal investigator for the project is Jennifer Wilcox from Worcester Polytechnic Institute. In 2018, she gave a TED talk that outlines some of the ideas behind her carbon removal research:

A new way to remove CO2 from the atmosphere. TED talk by Jennifer Wilcox.

I find Jennifer Wilcox’s talk very helpful for better understanding the energy and other requirements of carbon capture and removal.

Brimstone Energy

Brimstone Energy got an SBIR grant to develop a new technology for producing CO2-free hydrogen, and cement as a byproduct. The idea is to produce materials that can replace CO2-intensive cement by less CO2-intensive alternative materials.

Principal investigator for the project is Brimstone Energy co-founder Cody Finke. In a short statement for the World Materials Forum 2020, he describes the rationale behind Brimstone Energy’s work:

Brimstone Energy co-founder Cody Finke describes the rationale behind Brimstone Energy’s technology for making cement from alternative materials.

Brimstone Energy is a project of Cyclotron Road. Cyclotron Road is a project of Berkeley Lab, in partnership with Activate. In addition, Brimstone Energy is in Chevron’s Technology Ventures Catalyst program.

Brimstone Energy and Cody Finke hold patents on their cement-making technology, for example this and this. My understanding (as a non-chemist) is that the patents refer to the cement-making part of their technology.

Skyre

Skyre‘s SBIR grant is for further developing and improving a CO2 scrubbing device for crewed spacecraft. Trent Molter, President & CEO at Skyre, is the principal investigator.

I could not find a lot of detailed information on the device. But if you want to operate a device onboard a spacecraft, it should be extremely reliable and low-energy-consuming. Both these aspects are certainly interesting in other contexts as well.

Aside from the SBIR project, Skyre also makes a device that converts CO2 into fuels (e.g. methanol) and commodity chemicals (e.g. formic acid). When you look at the schematic below (from Skyre’s website), and look at the buttons of the device, you get a sense of the size of the device:

Skyre's CO2RENEW system converts CO2 into fuel and materials. Image from Skyre's website.
Skyre’s CO2RENEW system converts CO2 into fuel and materials. Image from Skyre’s website.

Verdox

Verdox is an ARPA-E project. ARPA-E is the Advanced Research Projects Agency – Energy, at the U.S. Department of Energy. Co-founder and CTO at Verdox, Sahag Voskian, is the principal investigator of their SBIR grant. Since the SBIR grant description talks about “carbon capture from streams”, I first thought that Verdox does carbon capture but not carbon removal.

But then I did a 360° search on Verdox and Sahag Voskian in Mergeflow, in order to get some more context (so far, verdox.com does not have much content yet).

Verdox came out of the MIT Energy Initiative’s Carbon Capture, Utilization, and Storage Center and was developed by Sahag Voskian and his PhD advisor T. Alan Hatton (see this article).

If I understand it correctly, here is how their approach to carbon capture and removal is new: In order to adsorb CO2, you need a material called “sorbent”. And traditionally, one would vary temperature and pressure so that these sorbents do their job. And this requires a tremendous amount of energy. By contrast, Verdox uses electricity to trigger the sorbent, which requires a lot less energy. It’s my understanding that this becomes possible by using quinones, which are organic compounds.

My search also turned up some patents, for example:

Methods and systems for removing CO2 from a feed gas.

Production of chemical products using electrochemical flow systems and slug flow and associated methods.


Related: Using patent classes for concept search.


Some carbon capture and removal R&D collaboration networks

Now let’s move from companies to science. Although in this case, there is a strong overlap, as you will see below.

For this section of my article, I used Mergeflow’s network graphs tool to discover and explore some of the more prominent R&D collaboration networks. As explained in another article, on how you get better search results for tech discovery, Mergeflow uses co-authorship networks, not citation networks. This is because citation networks usually take years to grow. Co-authorship networks are much more current.

So, what follows are some co-authorship networks, along with some example papers, for carbon capture and removal. And keep in mind that for this search, I only looked at publications from January 2020 until now (March 2021). Furthermore, I used the names of the most prominently featuring institutions from each network as headline. But each network also includes researchers from other universities and research institutes.

University of Minnesota and Huazhong University of Science and Technology

Eric Ganz, Hui Zhang and Li-Ming Yang play central roles in this network.

Co-authorship network involving scientists at the University of Minnesota and Huazhong University of Science and Technology.
Co-authorship network involving scientists at the University of Minnesota and Huazhong University of Science and Technology.

From what I understand, metal-organic frameworks (MOFs) are at the center of their research. Here is a recent example paper:

Properties and Detailed Adsorption of CO2 by M2(dobpdc) with N,N-Dimethylethylenediamine Functionalization

According to Wikipedia, MOFs are porous polymers.


Related: How to use Wikipedia to boost your discovery skills.


And according to Mergeflow, MOFs have seen increasing R&D activity over the past five years:

Science publications on MOFs have been rising over the past five years. Screenshot from Mergeflow.
Science publications on MOFs have been rising over the past five years. Screenshot from Mergeflow.

Worcester Polytechnic Institute

Jennifer Wilcox, Noah McQueen, Peter Psarras, Jiajun He, Hélène Pilorgé and Kourosh Kian are the most central researchers in this network:

Worcester Polytechnic Institute scientists collaboration network.
Worcester Polytechnic Institute scientists collaboration network.

We encountered Jennifer Wilcox already, when we looked at the SBIR grant for Community Energy. This is the overlap between business and science I referred to above.

Here is an example paper, Hélène Pilorgé is the first author:

Cost Analysis of Carbon Capture and Sequestration of Process Emissions from the U.S. Industrial Sector

Interestingly Hélène Pilorgé also works at Carbon Direct, one of the investors at Svante (see above).

Massachusetts Institute of Technology

Cameron Halliday, Alan Hatton, Nil Ozbek and Miao Wang are the most-connected scientists in the MIT carbon capture and removal network. And, another science-business connection, Sahag Voskian (see the section on Verdox above) is part of the network as well.

MIT carbon capture and removal scientists network.
MIT carbon capture and removal scientists network.

My layperson’s understanding of this group’s work is that their focus is on energy-efficient sorbent materials (the materials that adsorb the CO2). Plus the materials in the wider context, so that one can build a carbon capture system with compatible materials (so that, for example, issues like corrosive oxidation are avoided). Here is an example paper:

Understanding Material Compatibility in CO2 Capture Systems Using Molten Alkali Metal Borates

Zhejiang University

When you do a centrality analysis of a network, you can identify important nodes in the network (“important” = “high degree of centrality”). “Important” here means “if this node didn’t exist, the network would fall apart into individual sub-networks”.

For the scientist network around Zhejiang University, Jun Liu forms such a node. I marked him with a blue rectangle in the screenshot from Mergeflow below:

Zhejiang University scientist collaboration network.
Zhejiang University scientist collaboration network.

Here is one of his most recent publications:

Selectable Microporous Carbons Derived from Poplar Wood by Three Preparation Routes for CO2 Capture

The idea here is to use biomass-derived materials for CO2 capture. In other words, using sustainable materials as sorbents for carbon capture.

Carbon capture and removal: What are the numbers?

To wrap things up, let’s look at some numbers. How much impact can some of the technologies I described above actually have?

According to the IEA, in 2019, global energy-related CO2 emissions were 33,000,000,000 tons. I don’t know if “energy-related” also includes transport, for example. But let’s take this number as a lower bound.

Then, for the technologies I described in this article, and where I could get numbers, we have:

  • Carbon Clean Solutions say that since 2009, they have captured (not removed) 905,566 tons CO2. So this is roughly 82,000 tons of CO2 per year.
  • Svante say that one of their plants captures ca. 1,000,000 tons of CO2 per year.

(I assume that for the other technologies, it is simply too early to tell)

So, if we wanted to go to “zero new CO2 emissions” just by using these technologies, we could either scale up Carbon Clean Solutions by a factor of 402,000, or build 33,000 Svante plants.

I know that these technologies are not the only ones out there. And according to a report by the Global CCS Institute, which you can request here, “CCS facilities currently [2020] in operation can capture and permanently store around 40,000,000 tons of CO2 every year”.

So currently, we emit at least…

33,000,000,000 tons

…of which we can currently capture…

40,000,000 tons

And this doesn’t even include the CO2 that is in the atmosphere already. I guess this really drives home the enormity of the challenge.


Featured image by DAPA Images.

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