Varun Sivaram

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In Defense of CCS

by Michael Levi
May 14, 2010

Bashing carbon capture and sequestration (CCS) is a popular game these days. The latest installment is a Robert Bryce op-ed in today’s New York Times. It presents the standard arguments against CCS with admirable clarity, which provides a nice opportunity to explain why they’re wrong.

Argument #1:

“Capturing the carbon dioxide cuts the output of a typical plant by as much as 28 percent. Given that the global energy sector is already straining to meet booming demand for electricity, it’s hard to believe that the United States, or any other country that relies on coal-fired generation, will agree to reduce the output of its coal-fired plants by almost a third in order to attempt carbon capture and sequestration.”

This is a nice bit of sleight of hand. The United States is not straining to meet booming demand for electricity, nor is any other developed country, so this resource penalty is a non-issue for them. This is, however, a real problem for big developing countries like China. It’s why CCS is going to be a trickier proposition for them. That said, the timeline for CCS is at least a decade away, at which point this constraint may have changed.

Argument #2:

“Carbon dioxide is a worthless waste product, so taxpayers would likely end up shouldering most of the cost….”

If you have no interest in dealing with greenhouse gas emissions, then this argument kills CCS. If greenhouse gas emissions are an issue – and that’s the only reason anyone is talking about CCS – then this completely misses the point. It will cost money to reduce emissions. CCS may be too expensive, in which case people will need to focus on other options. It may be relatively cheap, in which case it will be the way to go. The fact that it costs more than zero tells you almost nothing.

Argument #3:

“In 2009, carbon dioxide emissions in the United States totaled 5.4 billion tons. Let’s assume that policymakers want to use carbon capture to get rid of half of those emissions – say, 3 billion tons per year. That works out to about 8.3 million tons of carbon dioxide per day, which would have to be collected and compressed to about 1,000 pounds per square inch (that compressed volume of carbon dioxide would be roughly equivalent to the volume of daily global oil production). In other words, we would need to find an underground location (or locations) able to swallow a volume equal to the contents of 41 oil supertankers each day, 365 days a year.”

No one is proposing storing 3 billion tons of U.S. carbon dioxide emissions each year. Let’s say we’re talking about cutting 80% off the 5.4 billion tons that the United States currently emits (which is at the aggressive end of the spectrum). 38% of U.S. energy comes from coal. Let’s assume that the entire electricity sector needs to be decarbonized to hit the 80% goal, that a third of that is eliminated through increased efficiency, and that another third is knocked out through greater use of nuclear and renewable energy. That means that 13% of U.S. emissions, or 700 million tons a year, would need to be dealt with through CCS. This is a very crude estimate – it could easily be off by a factor of two either way, but even then, it’s not 3 billion tons.

And despite Bryce’s suggestion, there’s probably enough space to store that. DOE estimates that there’s 138 billion tons of potential storage in oil and gas reservoirs in the United States and Canada, nearly two hundred years at my guestimated rate.

To be fair, Bryce does make a solid point when he says that “there will also be considerable public resistance to carbon dioxide pipelines and sequestration projects.” I think policymakers under-appreciate this. There is strong resistance to Yucca mountain despite solid scientific reasons to believe that it’s safe. My guess is that CCS storage will face similar suspicions.

CCS has problems. It needs massive and risky capital investment to scale up and bring down costs to a point where it might be competitive with other low-carbon alternatives. The resource penalty will deter deployment in China. Low-quality coal will deter deployment in India. It is far from certain that it will be a core part of the answer to climate change. These are all serious issues that policymakers need to confront. The ones that Bryce raises aren’t.

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  • Posted by jim hardy

    Hello Mr Levi:

    I’m a retired engineer from the utility industry. I worked thirty years in power plant maintenance as a hands-on guy not a paper pusher.

    To grasp this issue takes rudimentary appreciation of freshman thermodynamics which unfortunately most journalists and politicians lack.

    All three of your arguments are erroneous.
    #1 “…so this resource penalty is a non-issue for them. ” Reducing a plant’s output by 1/4 means you have to put at least that much more coal through it to return to same output. That extra coal has to be bought, mined, shipped and handled. That expense alone is a horrific drag on a struggling economy, not to mention its environmental impact.

    [ML: Thanks for the thoughtful comment — always glad to have reactions from people with hands-on experience. Some reactions, point by point. Yes, the extra coal needs to be bought/mined/shipped/handled. This is an extra cost. It may or may not be greater than the extra cost of other low-carbon options. But it is different from the hard constraint that Bryce invokes. Regarding a struggling economy, no one is talking about large-scale CCS for another decade. The economy better be back in shape by then.]

    #2: “If greenhouse gas emissions are an issue – and that’s the only reason anyone is talking about CCS – then this completely misses the point.” No, the reason they are talking about sequestration is it’s so expensive it’ll drive up the value of Carbon Credits. Period. As Al Gore said, The (political) science is settled.

    [ML: Expensive options don’t drive up the value of carbon credits. The entire point of cap-and-trade is that it lets you ignore the expensive options if cheaper ones are available.]

    #3: “Let’s assume that the entire electricity sector needs to be decarbonized to hit the 80% goal, that a third of that is eliminated through increased efficiency, ..”
    Sir, the physical work required to pump CO2 up to 1000 psi consumes perhaps a third of the energy you got out of producing that CO2. You applied the wrong sign to your delta(efficiency), it’ll be a decrease not an increase.
    Furthermore you stated the entire electric industry would be decarbonized but did not apply your numbers to oil and gas fired generation.

    [ML: Efficiency here refers to end-use efficiency, ie using less electricity in the first place; hence the correct sign. Re gas (there’s basically no oil in power generation), I assumed that it’s replaced in the same way that coal is (ie 1/3 efficiency, 1/3 nuclear+renewables, 1/3 something else).]

    The idea of adding to power plants the awful amine chemistry and HUGE compressors required for sequestration is just nuts.

    There’s always a third way out of a dilemma:

    Utility dispatchers love natural gas fired combined cycle generators because of their extreme thermal efficiency. Why spend trillions trying to clean up after coal, reducing power plant efficiency from 40% to 30% when you could simply burn natural gas at 60% instead?

    [ML: Important point, and makes substantial sense for at least a decade (and probably more). But unlike nuclear/renewables/CCS, it doesn’t ultimately get you to the long-term reductions we need.]

    Let us recognize sequestration as folly and instead build a natural gas infrastructure.
    The equipment is similar to your CO2 infrastructure, and by displacing large amounts of coal and diesel fuel it’d do something useful.

    old jim himself

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