The Case for Carbon capture

Carbon capture is the most underrated climate technology. Why? Because we’re wearing rose-colored glasses about the pace of emissions decline

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This Terraform Now Article answers the question “Why do we need carbon capture?” Carbon capture is a set of technologies used to take greenhouse gases out of Earth’s atmosphere, directly reducing global warming — if you want to go deeper on “what is carbon capture” check out Terraform Now’s Carbon Capture Primer.

Terraform Now: A Carbon Capture Primer

Despite it’s clear impact and massive potential, not everyone agrees that we should be scaling carbon capture. Some environmentalists actively discourage its use. Even among carbon capture advocates, it remains extremely underrated, with major climate outlets putting it near the bottom of their ‘most important climate tech’ lists.

I’m not a climate doomer. I don’t believe fossil fuels are inherently bad. I don’t see climate change as an extinction-level event, and I believe we’ll innovate our way out of this. But when I do the math, I don’t see how we work around climate change without carbon capture or some other planetary scale technology like blasting massive amounts of sulfur into the sky, or building a giant sunshade in space. Carbon capture seems to be by far the best solution out there.

TLDR, this Article will make a few claims:

• Given optimistic assumptions about rapidly declining emissions, carbon capture will be an important technology in mitigating historic emissions, ‘sticky’ emissions, and as a failsafe

• Economic development and current trends suggest that the optimistic emissions scenario is unlikely — a slower pace of emissions decline is more realistic

• Given realistic assumptions about declining emissions, carbon capture will be absolutely essential in keeping atmospheric temperatures from spiraling out of control

THE OPTIMISTIC CASE

It’s easy to walk away from most public-facing climate change stories with the idea that when the world moves to a 100% renewable energy system climate change will be mostly solved. A “renewable energy system” is a new economic paradigm, where almost all of the energy we produce and consume comes from sources that do not emit carbon dioxide or other greenhouse gases. For a bunch of reasons, I don’t think this will happen, and I’ll cover that later.

For now, let’s take this Optimistic Case at face value, assuming a wholesale replacement of fossil fuel infrastructure with renewables in the next two decades. This is basically the same as the International Energy Agency’s (IEA) Net Zero scenario. Global emissions would look something like this:

The graph seems to show emissions hitting a high in 2019 then declining in 2020. But we all remember what happened in 2020, and 2021 emissions (not shown in this chart) bounced back above pre-pandemic levels. In 2022, emissions grew by ~1%. So we haven’t yet reached peak fossil fuel.

One issue with the Optimistic Case is that it’s not all that optimistic — temperatures will still rise 1.5 degrees Celsius. This means intolerably hot days in some parts of the global south, drastic changes to soil moisture in our best farmland, and extreme weather events. But this graph is comforting, in part because we see emissions declining, and it’s easy to reason from there that the problem of greenhouse gases will just go away.

That’s not how it works. Greenhouse gases are cumulative, and most of them aren’t going anywhere. To be more precise, some greenhouse gases will go away quickly, like methane — it takes a decade or two for methane to break down in our atmosphere. But the most common greenhouse gas, carbon dioxide (CO₂), stays in the atmosphere for centuries:

If you go outside in 2023 and release 100 units of CO2 and 100 units of CH4 into the atmosphere, over 80% of the CO2 will still be warming the planet in 2050, while the CH4 degrades much faster

We care about solving the climate crisis on the timescale of decades, not centuries. Because CO₂ is both abundant and degrading slowly, we should focus on taking it out of the atmosphere. That’s why carbon capture, focused on CO₂, has to play a role. Carbon capture will have three jobs in the Optimistic Case:

• Eliminate historic emissions: We’ll have something like 2 trillion tons of excess CO₂ in the atmosphere in 2050, and carbon capture can help us get rid of that. Because even a planet that is 1.5 degrees C warmer is still scary, there’s a good case for prioritizing this even if global warming is not as bad as doomers predict.

• Make up for ‘sticky’ emissions: We’ll probably find out that some parts of the economy are way harder to decarbonize than we thought. Agriculture, which accounts for ~20% of emissions, might end up being the most sticky.

• Insure against rogue actors: Believe it or not, a few countries might benefit from global warming. Some climate scientists argue that some warming would open up more of Russia to year-round agriculture. For this and other reasons, it’s not that hard to imagine Russia or other revanchist countries continuing to burn fossil fuels well into the 2050s. In this scenario, some countries might scale carbon capture to counter rogue nations.

In the Optimistic Case, Carbon capture needs to handle about 7 billion ton of emissions in 2050, but renewables will account for 30+ billion tons of emission reduction.

I’d love to live in a world where renewable energy and behavior changes lead to a massive decline in our fossil fuel use. But I don’t think we’ll get there by 2050 — the next section explains why.

FOSSIL FUELS CREATED MODERNITY

A brief history of energy will put the project of weaning ourselves off fossil fuels into perspective.

From the dawn of humanity to about 1750 AD, we were energy poor. Then we discovered vast amounts of coal, oil, and gas buried underground, all of them bursting with potential energy. A new way of innovating, what we call ‘science,’ emerged at around the same time, helping us create things that combusted fossil fuels, turning all that potential energy into actual energy.

It’s astonishing how many problems some countries were able to solve with a massive infusion of cheap energy:

• Reduce poverty, slowly from 1850-1950 and at an accelerating pace from 1950-2023

• Grow the population, often by more than 10x

• Mechanize agriculture & transportation, enabling surplus labor to do other activities

• Reap the agglomeration effects of big cities, universities, incubators, and many other innovative institutions, leading to all sorts of inventions that have made our lives better, longer, and more enjoyable

• Reduce the wealth & power gap between the elite and regular people, creating the first middle class in history, enabling slow-moving political revolutions that led to greater freedom & political rights (even in autocracies)

• Take on world-altering projects, like exploring the world’s continents, going to the moon, building high-speed rail, and vaccinating a few billion people from polio, smallpox, and other diseases

Fossil fuels are the rising agent that allowed us to bake the cake of modernity. Even if fossil fuels were the active ingredient, they weren’t the only ingredients — for example, corporations and property rights played key roles. And of course there were plenty of unsavory ingredients mixed in, like interstate rivalry, naked imperialism, war and exploitation.

Of course fossil fuels are far from perfect. Combusting them creates nasty by-products, a problem that became obvious immediately. A sickening smog settled over the industrial towns of North England, and blanketed cities the world over. The problem of pollution has been solved in some countries by moving the dirtiest factories away from city centers. We do this, at enormous cost, because urban pollution is tangible: we feel it in our lungs and see it in our skies. Governments score quick wins by regulating urban pollution out of existence.

Greenhouse gases (GHGs), another nasty by-product of fossil fuels, are different. Unlike urban smog, GHGs are invisible, their effects incremental rather than sudden. Like urban pollution, we were never going to do anything about GHGs until they began to directly impact our lives.

And here we are. While terms like “climate emergency” and “climate crisis” feel a bit hyperbolic to me, reading about heatwaves, wildfires, and the prospect of much worse makes me understand why some folks use these terms. It’s clear to most reasonable people that we should do something about global warming. But ‘doing something’ about climate change is the most important issue for a very small minority of Earth’s population, which is why the Optimistic Case isn’t realistic.

CLIMATE PLEDGES, MEET REALITY

Most countries have something called a climate pledge, a promise to deliver a certain emissions profile by a specific year. For example, China’s climate pledge promises that emissions will peak in 2030 and go to 0 by 2060. If you take the climate pledges of all the world’s countries, you get an emissions profile that follows the yellow line:

The climate pledges scenario has way more emissions than the Optimistic Case! And these pledges are not even credible:

• Pledges are non-binding, so there’s no penalty if countries don’t meet them

• Pledges are made to the international community, not actual constituents of the governments; they’re not a promise to voters

• Pledges are generally made by old politicians who are likely to be out of the game by 2040

• Pledges do not align to actual plans. Each country has plans or projections for how their energy infrastructure, agriculture, etc., will develop. These plans are generally not used to calculate climate pledges. Especially in Asia, plans usually involve a lot more coal and natural gas than stated in their climate pledges.

Climate pledges are diplomacy masquerading as reality. I think that our actual emissions will be well above the yellow line.

EVEN THE ‘EASY’ TRANSITIONS WILL BE HARD

There are a lot of areas of the economy where decarbonization will be very hard — airplanes, cement, chemicals, agriculture, and more. Let’s ignore those for now and focus just on one big emissions source that’s supposed to be easy to shift to renewables: electric power generation. Coal is a good place to start, since it is, in theory, the easiest fossil fuel to abandon, being very dirty and more expensive than renewables.

If the optimists were right, we would see plans for rapid phase-out of coal in the next few years. Sadly, that’s not in the cards. The next graph shows current coal consumption, the coal consumption we need in 2030 to meet climate pledges (blue), and the amount of coal we are actually projected to burn in 2030 (red):

Country leaders have pledged to reduce coal from 8 billion tons today to just 2.6 billion tons in 2030. But demand is likely to be over 6 billion tons in 2030. According to The Economist and the IEA, almost 80% of this demand will come from Asia, with over half from China.

Leaders in China, India, and countries across Asia, Africa, and Latin America would say that the cake of modernity is only half baked, which means they will use fossil fuels to speed their development. And they won’t follow the Western playbook of energy development — which was something like ‘use a bunch of fossil fuels for a century or two, then dabble with nuclear, solar, and wind.’ They’ll look to emulate China, which has created a new playbook for energy, developing many modes of generation all at once. Call it the ‘all-in’ playbook:

The ‘all-in’ playbook calls for simultaneously building every source of energy. It’s about going big on coal, gas, nuclear, solar, and wind in a few decades. Emissions profiles are secondary to having an abundance of energy for businesses and their growing middle class. That’s why China can be both the world leader in burning coal and the world leader in solar capacity. It is both the world’s biggest emitter of GHGs and the biggest producer of renewables.

Head scratching stuff, unless you adopt the Chinese point of view on energy, which prioritizes prosperity over emissions. For the most part, countries develop energy infrastructure to help regular people, most of whom are middle-class, aspiring middle-class, or poor. Most of these people are aspiring for better life for themselves and and their children. Emissions are far down their list of priorities.

China is part of the way through this journey, and countries like Indonesia are going to follow:

Indonesia, a country with the same population as the United States, could be ‘next up’ for rapid economic development. They will likely shift to more renewables like China, while also building out more coal-fired plants. Credit: Bloomberg

These countries will ignore the preaching of environmentalists. They will keep trying to bake the cake of modernity, in part using the tried-and-true ingredient of fossil fuels. From their point of view, economic stagnation or regression is much worse, and much more immediate, than the threat of climate change.

And we should take their point of view very seriously. Rooting for underdeveloped energy systems means rooting for much worse lives for billions of people. In terms of human well-being, economic stagnation or regression could be as bad or worse than climate change.

What will environmentalists do if, beginning in the late 2020s, a few large African countries follow the China model? Will they root for these countries to fail to pull their populations into the global middle class? Will they demand that western governments bomb the coal plants in poor countries? Unlikely.

The optimist’s rebuttal to all this is simple: these countries should prioritize the development of renewable energy over fossil fuel energy. While this is relatively easy to say, it’s very hard to do because it’s an energy system that has never existed in the history of humanity. There are good reasons for that — as we’ll see next, even the richest countries are having trouble developing entirely renewable energy systems.

WEALTHIER COUNTRIES HAVE PROBLEMS TOO

America, the EU, Japan, and other so-called ‘developed’ countries appear to be in a good position. Environmental awareness, more efficient use of energy, and lots of capital into renewables are reducing emissions:

But the trend is slow and steady; renewable energy is not scaling as fast as we’d like. In my view there are a few big things holding back renewables:

1. Baseload power

2. Surprises

3. NIMBY

Let’s take these one by one.

Baseload power is about providing consistent energy to the grid, around the clock. Truly renewable sources of energy like solar and wind are not baseload — it’s hard to predict when and how intensely the sun will shine or how hard the wind will blow.

Fortunately, there are two renewable-ish generation technologies that can provide baseload power:

• Battery backup: The idea here is to have massive batteries that store energy from renewables when we have too much of it, and release it when we have too little. This has its own issues, like the emissions of digging up the metals that go in batteries. These are being addressed with better battery designs, (e.g. iron based), battery recycling, and other innovative approaches. However this shakes out, it is a large project requiring a lot of capital and expertise, so will take time to scale.

• Nuclear: You probably have a good sense for how polarizing nuclear power is. For some folks, it is a magic elixir. For others, it is expensive, dirty, unsafe, and reminds them of the most terrifying weapons ever used. One thing we know for sure is that nuclear power warms the planet much less than just about any other source of energy because it hardly emits greenhouse gases. But simply because it is controversial, nuclear is likely to move at a slow enough pace that it won’t replace coal and gas as baseload power quickly. This pattern has played out in every developed country, with one notable exception: France. The French nuclear-powered grid, despite recent problems, is a marvel of the modern world.

Battery backup and nuclear suffer from similar problems: they are capital intensive, take a long time to build, and influential groups of environmentalists oppose them (to varying degrees). Countries tend to fall back on fossil fuel plants for baseload power.

Surprises: Near term priorities are often more important than climate change. When Russia invaded Ukraine and cut off Germany from most of its natural gas, the Germans had a tough decision to make:

• Door #1: Use less energy, have cold homes all winter, starve the economy

• Door #2: Have warm homes by burning coal while keeping their remaining 3 nuclear power plants open

• Door #3: Use less energy, but have warm homes by burning coal, which is dirtier than natural gas, to keep their homes warm, and shut down more nuclear plants

Germany often brags about having the most ‘Green’ governing coalition of any large country, and yet they chose Door #3, the option with the highest emissions. In 2022, nuclear energy production fell by about 50%, and Germany now gets ~31% of its energy from coal.

Countries will continue to have energy-related surprises, and I’d bet that they will always put the needs of citizens above emissions, regardless of political system.

NIMBY: It should be easy for America to move to renewables at a faster pace. It has very good geography, with a lot of sun and wind. America is considered ground zero for creative disruption. And in 2022 Congress passed a massive climate bill meant to accelerate all things Green. So why aren’t renewables moving faster?

A big factor is Not In My Backyard, or NIMBY, a catchphrase for people who oppose building new things, including wind turbines or solar plants, near their homes.

NIMBYs use an act of Congress called NEPA to sue big projects, slowing them down, hampering them with extra requirements, and making them too expensive to finish. The result: even in areas where solar + wind + battery backup combo is much cheaper than fossil fuels, we are failing to install renewables. This has become much worse in the last decade, just as renewables have been ramping up:

These delays are absolutely crushing, making renewable projects unprofitable. According to Berkeley Lab, only 15-20% of projects waiting for approval are ever completed.

OK, now that we’ve covered the hurdles to reducing emissions — for both developing and developed countries — let’s zoom out and consider a realistic emissions scenario and what it means for carbon capture.

A (MORE) REALISTIC CASE FOR CLIMATE CHANGE

This is my guess for where emissions are actually headed:

If you sum up country-by-country energy plans, as the IEA has done, it gets you to emissions on the lower end of that red range. It is hard to predict the future, and I’m not saying that the red range is definitely where we are headed. But I do think that the assumptions underlying the Optimistic Case are very flawed, and that the red range represents a More Realistic Case — somewhere higher than the not-so-credible Climate Pledges.

While this emissions profile looks bad — I’ve even shaded it red to heighten the drama — it’s hard to root against this because, again, it probably means a few billion people joining the global middle class. This is not a world where a bunch of Swedes start driving gas-guzzling SUVs. It’s a scenario where African and Southeast Asian nations bake the cake of modernity.

This is where carbon capture could play a massive role, bridging the gap between reality and the dream of net zero:

The Realistic Case will require taking out a lot more carbon than we currently anticipate, and fast. Even if we assume that the ocean, plants, and soil absorb half of the CO2 we emit, that still leaves about 6.5 billion tons of of excess emissions per year in 2030. That’s about 4x what would be needed in the Optimistic Case:

Said differently, the more we delay progress on climate change, the more critical carbon capture becomes. To be a bit more precise about the role of carbon capture, different technologies will need to play different roles:

• Emissions’ Source carbon capture will need to mitigate current emissions, covering 20-50% of in-year emissions from power plants and waste-to-energy sites.

• Direct Air Capture will need to mitigate the remaining 50-80% of current emissions and make up for any shortfall from prior years. In other words, the longer we delay decarbonization, the larger the role DAC will need to play in the future.

The good news? There are a ton of highly motivated companies, and emerging coalitions of government support in both Europe and America. What’s needed next? Carbon removal needs early test markets, with companies and consumers that are willing to pay for carbon removal. Terraform Now will be publishing articles about all of these topics in the coming months.

Opinions expressed on Terraform Now do not represent the views of my employer, Bain & Company. Facts presented here are publicly sourced unless otherwise noted.