9 min read

CCUS: Carbon Capture, Utilization and Storage

Abstract: Business can't succeed in a world that'll be increasingly dictated by the impacts of climate change. Not tackling climate change could cost trillions of dollars while tackling it could be seen as trillion dollars of opportunities. While tracking carbon emissions will definitely help us better understand the impact, only though capturing, utilizing or storing carbon can we fight climate change.

Introduction

The underlying principle behind progress evokes knowledge, transformation and wealth. Human knowledge can transform a raw material that is of no particular use into something that has tremendous value, generating new wealth in the process. It is the ability to transform resources - from limestone to cement to skyscraper,

from sand to semiconductor to autonomous cars, and from chemical elements to alloys to Mars rovers - that has shaped the world we live in today. By transforming existing resources into new resources that never existed before, we have been consistently generating more wealth than ever before.

All of this involves energy, tremendous amounts of energy. While we have mastered the act of harnessing energy from resources such as oil and coal, it is clear that we have historically paid little attention to the waste and emissions created in the process. In that process, we have emitted over 2 trillion or 2 Gigatonnes of CO2 into the atmosphere. But is it possible that we can transform these waste/emissions, particularly CO2, into something useful or at the very least remove them from the atmosphere and store them safely?

Why can't we just reduce our emissions instead to tackle climate change? Well, there are multiple reasons. The supply of renewable energy sources is far away from the total energy demand. Switching existing industrial processes completely to renewable/ nuclear energy is hard as they need drastic infrastructural changes. The need for new energy storage solutions to help stabilize the natural intermittency of solar and wind energy as well as provide protection against power quality issues and power outages. And more importantly, even if we completely switched to renewable energy, to meet the target set at Paris Climate Accord, we would need to remove carbon from the atmosphere.

Credit: David Babson at Impact Tech

What about planting trees? That's the obvious natural and low-tech solution but the challenge is we release 33 million tons of CO2 every year and planting trees turns out to be an inefficient solution to capture that much carbon. It requires an enormous amount of time as well as land to grow forests and the scope is limited. The Amazon Forest is capable of capturing a little shy of 2 billion tons of CO2 each year. This is the equivalent of roughly 25 per cent of annual emissions just in the US. While companies like Dendra are working towards reforesting land, we need more efficient solutions aka synthetic forests that can accelerate our fight against climate change.

Technical Landscape

CCUS:

Enter Carbon Capture, Utilization and Storage (CCUS) technologies. The broad idea is at least half a century old. The technology broadly covers:

  • capture of carbon dioxide from industrial processes or from the atmosphere
  • transport the captured CO2 to the desired location to
  • either repurpose the waste feed as input resource or store permanently deep underground in geological formations.

CCUS technologies have the potential to drive the trend towards "net negative emissions" and perhaps reversing certain aspects of climate change.

Carbon Capture:

Credit: Carbfix

The first step is to capture carbon but the challenge is the proportion of carbon dioxide in the atmosphere which is 400 parts per million. This proportion is minuscule. Therefore, in order to capture sufficient carbon dioxide, there should be a large enough surface area to process all of the air required. This surface is called the air contactor. The carbon dioxide could be either captured by:

  • using CO2-grabbing chemicals dissolved in water or
  • using solid materials with CO2-grabbing chemicals

For example, the contactor is filled with a packaging material that has liquid distributed throughout it. The air is then bubbled through the liquid via fans. Strong-binding CO2 molecules in the solution separate the CO2 from the air.

The current CCUS technologies are predominantly focused on retrofitting existing fossil fuel-based power and industrial plants. Noya is a company that repurposes already-built and operating infrastructure such as cooling to capture carbon dioxide. NET Power, a US-based startup, is piloting an oxyfuel -  where the fuel is burned in oxygen instead of air resulting in a flue gas that is mainly CO₂ and water - combustion powerplant to capture a plant’s emissions at zero extra cost relative to conventional gas-fired power generation.

Global Thermostat, a US startup, uses low-cost leftover process heat to capture heat from power plants to reduce impacts from polluting cement smelters,  refineries and other industrial operations. Their process claims to remove 5 pounds of carbon dioxide per kWh of electricity, as opposed to 2 pounds of carbon dioxide for every kWh of electricity created by a coal-fired power station.

CO2 Solutions uses a natural enzyme that exists in all living organisms by leveraging solvent-based gas scrubbing techniques to quickly,  cheaply and efficiently absorb carbon with minimal energy expenditure.

Climeworks is a Swiss company that has developed a new filter material called the 'sorbent' in their CO2 collector. The technology utilizes a cyclic adsorption and desorption mechanism. During adsorption, the sorbent chemically binds the atmospheric carbon. Once the maximum capacity is reached, the collector is heated to a temperature between 80 and 100 deg C releasing high-purity high-concentration carbon dioxide. The sorbent can now be reused while the carbon dioxide is either sold to commercial industries or stored in natural sinks.

Carbon Engineering integrates an air contactor and a regeneration cycle to continuously capture atmospheric carbon dioxide as well as produce pure carbon dioxide.

Extracting CO2 from the air, where it is most diluted, requires more energy than what is needed to remove it from smokestacks. Silicon Kingdom Holdings and wholly-owned US subsidiary Carbon Collect Inc. are licensing and commercializing passive direct air capture technology called Mechanical trees. The design with large mechanical columns or disks contains CO2-absorbent material. No energy is required to capture CO2 as the technology relies on the wind to deliver CO2. Once the CO2 is absorbed, the disks are lowered inside a container where the CO2 is released from the sorbent. The released gas is then collected, purified, processed and put to other uses, while the disks are redeployed to capture more CO2.

Carbon Storage:

There are multiple ways to store carbon over the long-term.

  1. Biological carbon sequestration (planting trees, soil carbon enhancement etc.),

  2. Bioenergy with carbon capture and storage (BECCS):

    In a BECCS chain, CO2 from the atmosphere is absorbed via photosynthesis into plant biomass which is then deployed through either:

    • liquid biofuel production (biodiesel or bioethanol)

    • biomass conversion to heat and power

    This is then burnt or heated in industrial facilities or power plants to capture CO2 preventing their release into the atmosphere. However, the opportunity for BECCS is limited in helping reach climate targets since the scale of negative emissions that can be delivered is limited, and the value chain is complex with significant energy and carbon inputs..

  3. Direct air capture with geological storage (DACCS):

    It is not just forests and vegetation that bind carbon from the atmosphere, the other naturally occurring process is mineralization where huge quantities of carbon are naturally stored in rocks.

    Geological storage involves injecting CO2 captured from industrial processes into rock formations deep underground. This is because rock formations have enough millimetre-sized voids that provide the capacity to store the CO2. Additionally, they have high permeability allowing the CO2 to move and spread out within the formation.

    Basaltic rocks are one of the most suitable options since they are highly reactive and contain the elements needed for permanently immobilizing CO2 through the formation of carbonate minerals. They are often fractured and porous, containing storage space for the mineralized CO2. Given that Iceland is a natural home for basaltic rocks, there is tremendous interest there to leverage this technology.

    Carbfix is an Icelandic company working towards this. At first, carbon dioxide is dissolved in water and made to interact with reactive rock formations to form stable minerals providing a permanent and safe carbon sink.

  4. Enhanced Weathering

    This method involves spreading large amounts of pulverized silicate and/or carbonate minerals onto warm and humid land areas (EW) or onto the sea surface (OAE). Chemical weathering occurs with increased exposure of these minerals leading to atmospheric CO2 consumption. There are risks associated as we have lots of unknowns and perhaps second-order effects that may arise. More research needs to be done on this front.

Carbon Utilization:

Credit: Resourcse.org

The captured carbon could then be used to support the generation of low-carbon hydrogen. The demand for hydrogen is growing as it could be used for different cases such as:

Credit: Government of Ontario

Market Landscape

Solidia Technologies, a US startup backed by the oil and gas, chemicals, and cement industries and private equity, has developed a precast cement manufactured using CO2.

Solar Foods is an interesting Finnish company that combines air and electricity from renewable sources to create unique single-cell proteins that can be used as food nutrients. The technology splits water molecules into hydrogen and oxygen. It then combines hydrogen with CO2 while adding nutrients such as potassium and Sodium. This is then fed to microbes that create edible ingredients.

Bergen Carbon Solutions, a Norwegian company uses CO₂ to produce nanofibers. The only by-product they claim is O₂ -emissions. Carbon nanofibers are lighter than plastic but stronger than steel material with exceptional thermal and electrical conductivity. There is a growing demand for carbon nanofiber due to its unique properties.

Prometheus aims to convert the captured carbon into gasoline and jet fuel, thereby, offering carbon-neutral solution. By pulling CO2 and water from air and combing them with electricity from solar and wind, they produce net-zero carbon fuels.

By leveraging, biological organisms such as microbes and bacterium, a number of companies are striving towards repurposing captured carbon to useful resources:

Photanol leverages cyanobacteria to photosynthesize i.e absorb CO2 and adapt its metabolic pathways to produce a desired chemical. They transform bacterium into highly-efficient mini-factories that run on sunlight, less land and water while producing just oxygen as a by-product. The company claims to can create any carbon compound.  Monomers used for different plastics, the ingredients for personal care products and detergents; even fuels - clean, renewable and circular are among the products listed on their website.

iMicrobes is a company developing biomanufacturing solutions to create sustainable materials from low-cost gases. They leverage micro-organisms such as cyanobacteria and modify the microbes to convert inexpensive or waste greenhouse gases into new materials.

Oakbio is a US startup with 6 Million $ in funding that converts streams of waste carbon into readily marketable, high-value products such as food and feed products, bioplastics, and chemicals. Their technology combines CO2 and hydrogen which is fed into a bioreactor filled with microbe solutions developed at Oakbio. Different products are then produced based on the choice of microbes, design and process conditions.

What about the costs? Is it economically feasible to pursue CCUS?

Carbon Capture costs vary greatly by the source. For industrial processes that release highly concentrated CO2, the cost is around USD 15-25/t whereas for processes with “dilute” gas streams, such as cement production and power generation, the cost is between USD 40-120/t CO2. The cost of onshore pipeline transport is in the range of USD 2-14/t CO2,  while the cost of onshore storage shows an even wider spread from USD 10-100/t CO2. The costs are expected to decrease with advances in technology and more adoption.

Carbon storage costs can’t be compared to anything yet. Since, it is definitely much cheaper for industries to generate these emissions than reduce or capture, the only way for mass adoption of these technologies will be through voluntary commitments by companies or through (unfortunately) regulations, subsidies and carbon taxes.

However, solutions that gear towards carbon utilization can play a pivotal role in accelerating the carbon economy. If companies can attain cost-parity in producing sustainable materials for industrial solutions, carbon utilization could be the best bet against climate change.

Resources:

The International Energy Agency has some great resources and reports on the advances and challenges pertaining to CCUS.

Carbon Direct is a firm that provides advisory services and invests in carbon removal technologies at scale. Check out this podcast for a quick masterclass on carbon removal.

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