Direct Air Capture: The Key To Reversing Climate Change

By Dr. Graciela Chichilnisky, co-founder and CEO of Global Thermostat and co-author of Reversing Climate Change, and Professor of Economics and Mathematical Statistics at Columbia University.

Special to The Digest

The pace of global climate change is accelerating. So is our understanding of what it takes to avert catastrophic climate change. The world’s power plant infrastructure is the largest source of emissions, which is set to increase dramatically: power plants globally represent about $55 trillion in global revenue today, and by 2050, energy use is widely expected to double in developing nations.

In the long run, we must produce energy from clean sources that do not emit carbon dioxide. However, the implementation of this long-run solution will take decades, and we are running out of time. Once emitted, carbon dioxide can remain for hundreds of years in the atmosphere. The United Nations is urging significant action on these emissions in the next 12 years. We don’t have time to wait. Something else must be done now: that is, the physical removal of the carbon dioxide that is already in the atmosphere.

But how do we do what it takes? It has been difficult enough so far to reduce carbon dioxide emissions. How do we reverse the process entirely and remove the emissions that are already in the atmosphere as needed to reverse climate change?

A few companies are building “direct air capture” (DAC) plants that use chemical agents to scrub trace amounts of carbon dioxide from the air, allowing them to sell the gas to industrial customers or bury it underground. 

For example, Global Thermostat (GT) has created, developed and patented a proven breakthrough technology that can cost-effectively remove carbon dioxide directly from the atmosphere. GT’s technology is now commercially available and has the potential to fundamentally change the way we manage and utilize carbon on a global scale, including the use of carbon dioxide instead of petroleum, which represents an economic revolution of sorts. Since these emissions are considered a leading cause of climate change, and current concentrations in the atmosphere (400 ppm) are at their highest level in the last 3 million years, GT has the power to turn this major liability into a valuable commodity that can serve a carbon dioxide market spanning a wide range of industries, including water desalination, biofertilizers, food and beverages, production of polymers and carbon fibers, synthetic fuels, enhanced oil recovery, and more — a rapidly growing carbon dioxide market that McKinsey, the global consultancy, anticipates can generate $1.1trillion annually.

The principal advantages and characteristics of the Global Thermostat technology are as follows:

(1) it provides carbon dioxide that can be monetized as a replacement for fossil fuels;

(2) it has low capital costs;

(3) it has a scalable design that is highly modular;

(4) it has a low variable cost that represents a cost breakthrough, as it is powered by free or low-cost, widely available residual low temperature (85°C) heat;

(5) it slashes transportation costs, as carbon dioxide can be produced where used, requiring no transportation;

(6) it is a carbon negative solution that suffices to redress climate change, since the captured carbon dioxide can be sequestered in carbon fiber, into “aggregate” and other building materials that can replace steel, aluminum and concrete, and costs less than the materials replaced, a market that can absorb 10 gigaton of CO2 per year;

(7) it has easy integration into upstream energy production or downstream CO2 utilization.

In high-level terms, the technology consists of a unique, proprietary, low-cost process to capture carbon dioxide from the atmosphere (at concentrations of 400 parts per million). It can also capture the gas from industrial flues or chimneys (with 5% to 7% concentration or more), or from any combination of the two. As of 2019, GT has been awarded 61 patents in the U.S. and internationally, and by treaty it is protected in 152 nations. These patents cover the entire process for the low- cost loading and unloading of carbon dioxide from a porous block monolith coated with proprietary sorbents to produce >98.5%–99% pure carbon dioxide gas stream at atmospheric pressure.

Here is a snapshot of how GT’s technology works: Air and/or a flue gas mixture are moved by fans over a wall of honeycomb monoliths, which are coated with a proprietary ‘sorbent’ (amine-based chemical). The coated monoliths absorb the carbon dioxide. Steam produced from residual heat sources is used to desorb the carbon dioxide from the wall. High purity carbon dioxide is recovered. A Concentrated Solar Power (CSP) power plant can be used to drive the process, making it most effective in terms of carbon removal while producing carbon dioxide free electricity.

The purity level of the carbon dioxide gas recovered by GT’s process is as high as 99%, and the carbon dioxide stream exits at one atmospheric pressure; it can be further purified and/or liquefied using standard “compression” techniques, to be used for food and beverages applications.

Since transportation costs for large volume gaseous carbon dioxide are significant and can run as high as $1.5 million per mile for a pipeline plus compression, producing the gas on site drastically reduces or eliminates these costs. A carbon dioxide air capture plant can be located anywhere, needing only air and heat to operate. It can be built next to an oil field or a food processor, and it can be located anywhere there is air, thus eliminating the need to truck or pipe the CO2 over a long distance.

Conventionally, carbon dioxide in ambient air, which is now about 400 parts per million and uniform throughout the planet’s atmosphere, has been considered too dilute to be captured economically. As a result, the focus of carbon dioxide capture applications has been on flue gas and other point sources in which there is up to 300 times more carbon dioxide concentration than in the atmosphere. GT’s ability to capture unlimited amounts of the gas from ambient air creates efficiencies by allowing more mass to pass through a larger surface area. GT also blends flue gas with ambient air, optimizing carbon dioxide concentration and temperature.

We know that power plants are the main source of carbon dioxide emissions, comprising about 45% of the world’s emissions. What is less known is that the combination of conventional power plants with GT technology can transform the world’s $55 trillion power plant infrastructure into a sink of carbon dioxide emissions, cleaning the atmosphere. A conventional fossil fuel plant produces enough residual heat that it can drive a GT carbon capture plant to capture about twice as much carbon dioxide as the power plant emits itself in the first place. For example, a coal driven 400 MGW power plant emits between 1 and 2 million tons of carbon dioxide per year; the residual heat the power plant produces is generally enough, however, to capture twice as much carbon dioxide as the plant emits.

Carbon dioxide air capture has gained momentum on the policy front and in the business community as a viable and economic solution for reducing carbon emissions and is now being introduced commercially with pilot demonstration plants. The first GT pilot plant erected at SRI International in Menlo Park, California, captures 1,000 tons per year of carbon dioxide (although by changing its parts this can increase up to 10,000 tons per year) and was co-developed with Linde, Corning and BASF. The gas captured at plants like this is available for use in applications such as enhanced oil recovery, greenhouses, production of industrial grade formic acid, production of bio-fuels from algae, and, when combined with hydrogen, production of hydrocarbons such as high-octane gasoline.

With Direct Air Capture technology we can reverse the paradigm that links fossil fuel-based power production with carbon emissions. The time is now to reverse global climate change.

Dr. Graciela Chichilnisky, co-author of Reversing Climate Change (World Scientific Publishing, December 2019), is a Professor of Economics and Mathematical Statistics at Columbia University, and Director of the Columbia Consortium for Risk Management. She is also co-founder and CEO of Global Thermostat, and co-creator of a carbon removal technology that can reverse climate change. The technology was chosen by MIT Technology Review as one of the Ten Breakthrough Technologies of 2019, curated by Bill Gates.  In addition, Global Thermostat was named one of the top ten most innovative companies in energy by Fast Company and Dr. Chichilnisky was selected by International Alternative Investment Review as the 2015 CEO of the Year in Sustainability.  In 2019, Global Thermostat and ExxonMobil signed a joint development agreement to advance breakthrough technology to scale up to the removal of 1 gigaton of CO2.

Chichilnisky worked extensively on the Kyoto Protocol, creating and designing the carbon market that became international law in 2005. In 2017, she was selected by the Carnegie Foundation for their prestigious Great Immigrant, Great American award and in 2018, she was awarded the Albert Nelson Marquis Lifetime Achievement Award.

Chichilnisky holds Ph.D. degrees in mathematics and economics from MIT and the University of California, Berkeley. She is the author of over 300 scientific articles and 13 books, including Saving Kyoto which won the American Library Association’s 2010 Outstanding Academic Title of the Year and the American Geographical Society’s Book of the Month Award in October 2009.  She acted as the lead author on the Intergovernmental Panel on Climate Change which received the 2007 Nobel Prize for its work in deciding world policy with respect to climate change.